Border Security: Better Usage of Electronic Passport Security Features Could Improve Fraud Detection
Published: 2010-01-22T00:00:00

Fast Facts:

Highlights:
section_title: Why GAO Did This Study
paragraphs: In 2005, the Department of State (State) began issuing electronic passports (e-passports) with embedded computer chips that store information identical to that printed in the passport. By agreement with State, the U.S. Government Printing Office (GPO) produces blank e-passport books. Two foreign companies are used by GPO to produce e-passport covers, including the computer chips embedded in them. At U.S. ports of entry, the Department of Homeland Security (DHS) inspects passports. GAO was asked to examine potential risks to national security posed by using foreign suppliers for U.S. e-passport computer chips. This report specifically examines the following two risks: (1) Can the computer chips used in U.S. e-passports be altered or forged to fraudulently enter the United States? (2) What risk could malicious code on the U.S. e-passport computer chip pose to national security? To conduct this work, GAO reviewed documents and interviewed officials at State, GPO, and DHS relating to the U.S. e-passport design and manufacturing and e-passport inspection systems and procedures.
section_title: What GAO Found
paragraphs: State has developed a comprehensive set of controls to govern the operation and management of a system to generate and write a security feature called a digital signature on the chip of each e-passport it issues. When verified, digital signatures can help provide reasonable assurance that data placed on the chip by State have not been altered or forged. However, DHS does not have the capability to fully verify the digital signatures because it has not deployed e-passport readers to all of its ports of entry and it has not implemented the system functionality necessary to perform the verification. Because the value of security features depends not only on their solid design, but also on an inspection process that uses them, the additional security against forgery and counterfeiting that could be provided by the inclusion of computer chips on e-passports issued by the United States and foreign countries, including those participating in the visa waiver program, is not fully realized. Protections designed into the U.S. e-passport computer chip limit the risks of malicious code being resident on the chip, a necessary precondition for a malicious code attack to occur from the chip against computer systems that read them. GPO and State have taken additional actions to decrease the likelihood that malicious code could be introduced onto the chip. While these steps do not provide complete assurance that the chips are free from malicious code, the limited communications between the e-passport chip and agency computers significantly lowers the risk that malicious code--if resident on an e-passport chip--could pose to agency computers. Finally, given that no protection can be considered foolproof, DHS still needs to address deficiencies noted in our previous work on its computer systems to mitigate the impact of any malicious code that may be read from e-passport computer chips and infect those systems.

section_title: Letter
paragraphs: In 2005, the Department of State (State) began producing and issuing  electronic passports (e-passports). These new e-passports have an  embedded computer chip that stores information identical to that printed  in the passport, including the traveler’s name, date of birth, photo,  passport number, and passport expiration date. By comparing the  information contained on the chip with the information printed in the  passport, inspecting officials can more readily identify whether the photo  or the biographical information has been altered or counterfeited, which  provides greater assurance of the integrity of the passport.
State’s Bureau of Consular Affairs is responsible for the design and  issuance of passports, and U.S. Customs and Border Protection (CBP) in  the Department of Homeland Security (DHS) inspects the documents at  ports of entry to the United States. By agreement with State, the U.S.  Government Printing Office (GPO) produces blank e-passport booklets.  Among the many components that are used to make e-passport booklets,  GPO has contracts with two European companies to produce the   e-passport covers, including the manufacturing and inlaying of the  computer chips into the e-passport covers. Both European companies use  subcontractors in Asia for parts of the work. Concerns have been raised  that the use of foreign-produced computer chips introduces risks to the  integrity of the U.S. e-passport.
In response to your request, this report focuses on potential risks to  national security posed by the use of foreign suppliers for U.S. electronic  passports. Specifically, it examines the following two risks: (1) Can the  computer chips used in U.S. e-passports be altered or forged to  fraudulently enter the United States? (2) What risk could malicious code  on the U.S. e-passport computer chip pose to national security?
To determine whether e-passport chips can be altered or forged so that a  traveler could fraudulently enter the United States, we interviewed  officials from State’s Bureau of Consular Affairs and reviewed State  Department policies, procedures, and guidance documents regarding the  public key infrastructure (PKI) used to protect the data on the e-passport  computer chip and assessed them against relevant International Civil  Aviation Organization (ICAO) and National Institute of Standards and  Technology (NIST) standards and guidelines. We interviewed officials at  one passport agency and reviewed systems documentation to understand  how U.S. e-passports are personalized. We determined the extent to which  information stored on U.S. e-passport computer chips is inspected at U.S.  ports of entry by interviewing DHS and CBP officials and reviewing  documentation regarding the systems and procedures used to inspect   e-passports at the ports of entry.
To determine whether malicious code on the e-passport chips poses a risk  to national security, we determined how U.S. e-passport computer chips  are manufactured and incorporated into the production of blank U.S.   e-passport booklets based on interviews with GPO and manufacturer  officials and reviews of GPO documentation. We met with officials from  NIST and the National Counterterrorism Center to determine the level of  threat that exists to U.S. e-passports. We interviewed GPO and State  officials and reviewed documentation that describes the U.S. e-passport  computer chip architecture and operations. We reviewed documents  governing the manufacturing of the blank e-passport covers. We identified  protections that have been designed into the e-passport computer chip as  well as controls that are in place to reduce the possibility of malicious  code on the e-passport computer chip.
Additional details on our scope and methodology can be found in  appendix I. We conducted this performance audit from June 2008 to  January 2010 in accordance with generally accepted government auditing  standards. Those standards require that we plan and perform the audit to  obtain sufficient, appropriate evidence to provide a reasonable basis for  our findings and conclusions based on our audit objectives. We believe  that the evidence obtained provides a reasonable basis for our findings  and conclusions based on our audit objectives.
subsections: section_title: Background
paragraphs: U.S. passports are official documents that are used to demonstrate the  bearer’s identity and citizenship for international travel and reentry into  the United States. Under U.S. law, the Secretary of State has the authority  to issue passports, which may be valid for up to 10 years. Only U.S.  nationals may obtain a U.S. passport, and evidence of citizenship or  nationality is required with every passport application. Federal regulations  list disqualifying situations under which U.S. citizens are not eligible for a  passport, such as those who are subjects of a federal felony arrest warrant.
The security of passports and the ability to prevent and detect their  fraudulent use are dependent upon a combination of well-designed  security features, solid issuance procedures for the acceptance and  adjudication of the application and the production of the document, and  inspection procedures that utilize the available security features of the  document. A well-designed document has limited utility if it is not well  produced or if inspectors do not utilize the security features to verify the  authenticity of the document.
In 2005, State began issuing e-passports, which introduced an enhanced  design and physical security features. GPO manufactures blank e-passport  booklets for State using a variety of materials from different suppliers.  Currently, GPO has two suppliers—Infineon and Gemalto—under contract  for the covers of the e-passports. These covers include the computer chip  embedded in the back cover that can communicate using contactless ID  technology. Security-minded versions of this technology are employed in  contactless smart cards used in applications such as automatic banking  and identification. As of February 1, 2009, the State Department had issued  over 30 million e-passports.
subsections: section_title: Document Security Features
paragraphs: To combat document fraud, security features are used in a wide variety of  documents, including currency, identification documents, and bank  checks. Security features are used to prevent or deter fraudulent alteration  or counterfeiting of such documents. In some cases, an altered or  counterfeit document can be detected because it does not have the look  and feel of a genuine document. For instance, in U.S. passports, detailed  designs and figures are used with specific fonts and colors. While these  features are not specifically designed to prevent the use of altered or  counterfeit documents, inspectors can often use them to identify  nongenuine documents.
Security features of travel documents are assessed by their capacity to  secure a travel document against the following threats:    counterfeiting—unauthorized construction or reproduction of a travel  forgery—fraudulent alteration of a travel document, and impostors—use of a legitimate travel document by people falsely  representing themselves as legitimate document holders While security features can be assessed by their individual ability to help  prevent the fraudulent use of the document, it is more useful to consider  the entire document design and how all of the security features help to  accomplish this task. Layered security features tend to provide improved  security by minimizing the risk that the compromise of any individual  feature of the document will allow for unfettered fraudulent use of the  document. While most security features in the U.S. e-passport are physical  features, the introduction of the computer chip also allows for the use of  electronic security features.
section_title: Inspection of Travel Documents to Enter the United States
paragraphs: In general, at ports of entry, travelers seeking admission to the United  States must present themselves and a valid travel document, such as a  passport, for inspection to a CBP officer. The immigration-related portion  of the inspections process requires the officer to confirm the identity and  determine the admissibility of the traveler by questioning the individual  and inspecting the presented travel documents. In the first part of the  inspection process—primary inspection—CBP officers inspect travelers  and their travel documents to determine whether they should be admitted  or referred for further questioning and document examination. If  additional review is necessary, the traveler is referred to secondary  inspection—in an area away from the primary inspection area—where  another officer makes a final determination to admit the traveler or deny  admission for reasons such as the presentation of a fraudulent or  counterfeit passport.
section_title: E-passport Computer Chip Construction and Communication
paragraphs: The chips used in the U.S. e-passports are integrated circuits (IC) that are  essentially complete computers that contain a central processing unit,  various types of memory, and other components that perform specialized  functions such as random number generation and advanced cryptographic  processing. The chips contain both hardware and software. The hardware  circuitry and the operating system are implanted into the various layers of  the chip in a process called photolithography, which employs a technique  called masking wherein the chip’s circuitry is defined on a series of glass  plates called the photomask. The photomask is used as a template to  transfer the pattern of the chip’s electronic components into the various  layers of the physical chip. Once implanted, the circuitry is considered  permanent and not changeable except through physical attack.
While the chip’s operating system is implanted into the chip through the  photomask at chip creation time, other software needed on the chip—for  example, the traveler data—are written to the chip later, during  personalization of the chip.
The e-passports are designed as contactless proximity cards, and  communication with the embedded chip is only via a radio frequency (RF)  link established according to standard methods with a device generally  called a reader. To support global acceptance and interoperability of  e-passports, ICAO issued standards that define how data are to be stored  on and read from e-passports, including the RF communications.  According to the ICAO standards, contactless communication with the  e-passport is governed by ISO/IEC 14443, an international standard that  defines the transmission protocol used to transfer data between the reader  and the chip. Higher-level reading from and writing to the chip is  implemented through the ISO/IEC 7816-4 command set. ISO 7816-4 is an  international standard set of commands used to communicate with the  chip and to control all reading from and writing to the chip based on a  strict command/ response scheme. The reader initiates all commands to  the chip and the chip provides the expected response. The chip itself  cannot initiate any communications with the reader. ISO 7816-4 includes  controls to limit read and write access to the chip to authorized parties.
The United States issues e-passports with both ISO/IEC type A and type B  interface connections. Both types use the same transmission protocol, but  vary in how communications are established between the chip and the  reader and in how information is encoded for transmission.
The chip has no onboard power, but instead pulls the energy it needs from  the electromagnetic field emitted by the reader. The e-passport antenna  receives the electromagnetic energy from the reader and converts it to  electric current to power the chip. The chip can be powered and  communicate only when it is in close proximity—up to about 10  centimeters—to an appropriate reader. With both types of chips, the  antenna is a component external to the chip and separately attached to it  as part of the overall book cover manufacturing process.
subsections: section_title: The Software Contents of the Chip
paragraphs: While the communication protocols and command set are standardized,  the operating system and other software used on the chips are vendor- specific. As is typical with smart card ICs, the software on the e-passport  chips is partitioned into three general areas: the IC dedicated software, the  basic embedded software, and the application embedded software. The IC  dedicated software contains software used for testing purposes and  software to provide other services to facilitate usage of the hardware on  the IC. The IC dedicated software is developed by the IC manufacturer and  it is part of the photomasks of the chips.
The basic embedded software is typically not provided by the chip  manufacturer, but is usually developed by a third party and delivered to  the chip manufacturer for incorporation into the chip’s photomask. An  important component of the basic embedded software is the operating  system for the chip. The operating system implements the ISO 7816-4  command set and controls all communication between the chip and the  outside world.
The third major partition of software on the chip is the application  embedded software, which is also typically provided by a third party and  provides functionality specific to the particular application for which the  chip is intended to be used. In the case of the U.S. e-passports, the  application software is data contained in a file layout using an open, ICAO- specified logical data structure used for machine-readable travel  documents.
section_title: The E-passport Production Process
paragraphs: In producing e-passport booklets for State, GPO has tapped into the  existing global smart card industry, resulting in a wide number of different  companies involved in the e-passport chip production and inlay process.  Two separate companies were awarded contracts to supply chips for the  U.S. e-passports. Infineon, a German company, fabricates its own chips  and embeds a commercial operating system from a third-party company  on them. Gemalto, a Dutch company, obtains chips from NXP, a Dutch  semiconductor manufacturer. Gemalto provides NXP with its own  operating system, which NXP embeds within the chip prior to shipping the  chip to Gemalto.
Although each of these contractors takes a different path to create and  provide e-passport covers to GPO, both use a common subcontractor for  attachment of the antenna to the chip and the inlaying of the chip into the  back cover of the e-passport booklet. GPO itself finishes production of the  e-passport booklet by inserting the paper pages into the covers, installing a  metal strip down the inside spine for RF shielding, and, in a process  termed pre-personalization, preparing the chip for use by the State  Department. State personalizes the e-passport by printing bearer data onto  the data page and writing digital data onto the chip as part of its issuance  procedures.
subsections: section_title: Gemalto E-passport Chip and Booklet Production Process
paragraphs: As seen in figure 1, several steps are involved in the production of an   e-passport using Gemalto’s e-passport booklet. Gemalto involves several  subcontractors to produce the cover before it is delivered to GPO. For  instance, while the operating system software is created by Gemalto, it is  implanted on the chip when it is fabricated by NXP. Companies overseas  are also involved in the production of the chip and its incorporation into  the e-passport cover.
In pre-personalization, GPO tests and formats the chips, preparing them  for personalization by State, and finishes overall construction of the   e-passport booklet. GPO then ships the finished, blank e-passport books to  the 21 State Department passport issuing offices around the country that  then personalize and issue them to U.S. citizens, as needed.
Similar to Gemalto’s production process, the production process at  Infineon also involves several subcontractors to produce the booklet cover  before it is delivered to GPO (see fig. 2). The operating system and other  embedded software used on the Infineon chips are developed by a third- party company, and shipped to Infineon for incorporation into the  photomask pattern. As with the Gemalto production process, GPO tests  and pre-personalizes each chip, finishes the books, and distributes the  finished, blank e-passport books to the 21 passport-issuing offices.
section_title: Threats to E-passport Computer Chips
paragraphs: Since 1997, GAO has identified federal information security as a high-risk  area. Malicious code is one of the primary threats to federal information  security. NIST defines malicious code—sometimes called malware—as “a  program that is inserted into a system, usually covertly, with the intent of  compromising the confidentiality, integrity, or availability of the victim’s  data, applications, or operating system or of otherwise annoying or  disrupting the victim.” Malicious code can be used for many purposes  and come in many forms. For example, malicious code might be designed  to delete files on a system or repeatedly attempt access to a system service  and thus effectively shut it down. The effects of malicious code can range  from performance degradation to compromise of mission-critical  applications. Some common forms of malicious code include viruses,  worms, and Trojan horses. Viruses infect a system by attaching themselves  to host programs or data files. Worms are self-contained programs that can  self-replicate and do not require human interaction to spread through a  system or network. Trojan horses are nonreplicating programs that appear  benign but are designed with a malicious purpose.
Malicious code often takes advantage of vulnerabilities in a system’s  software to either spread or execute. For example, a common  vulnerability, known as a buffer overflow, redirects system control to a  malicious program through badly designed software. Inadequate controls  on a network’s connections or services are another common vulnerability  that allows malicious code to spread. Common protections against  malicious code include input checking at the boundaries of a system, such  as at external interfaces to a system; network controls to lower the  possibility that malicious code could spread within a system; and patch  management to address vulnerabilities in the system’s software that  malicious code can exploit.
In general, a successful malicious code attack first requires that the  malicious code get into a system. This can occur, for example, by inserting  infected media into the computer or through incomplete controls on the  system’s network connections. Second, the malicious code needs to  spread to those areas of a system to which it wants to cause damage.  Malicious code can spread in many ways, including various network  protocols and services and also in simple file transfers. Finally, malicious  code needs to be executed, often by taking advantage of vulnerabilities in  a system’s software.
Therefore, in the case of e-passports, a successful malicious code attack  from the chip would first require that malicious code get on the chip.  Second, that it get transferred from the chip onto agency computers  during the e-passport inspection process and then spread to vulnerable  areas within those systems. And, finally, the malicious code would have to  be executed.
Although communication with the chips is designed to be via the  contactless ID interface that complies with the ISO 7816-4 standard, which  includes an authentication procedure to limit read and write access to the  chip to authorized parties, an alternate, illicit way data can be attempted to  be read from or written to the chip is through physical tampering  techniques. In general, the aim of such an attack is to discover confidential  data stored on the chip—such as cryptographic keys—which can be used  to open access to the chip via the contactless interface.
section_title: Common Criteria
paragraphs: Common Criteria is an international standard method for evaluating  security features of information technology (IT) components. The U.S.  portion of this effort is coordinated through a partnership of NIST and the  National Security Agency (NSA) called the National Information  Assurance Partnership (NIAP). It provides a framework for evaluating  security features of IT components. The Common Criteria program  evaluates commercial-off-the-shelf information assurance and information  assurance-enabled products. These products can be items of hardware,  software, or firmware. Evaluations are performed by accredited Common  Criteria testing laboratories whose results are then certified by a validation  body. A product is considered Common Criteria certified only after it is  both evaluated by an accredited laboratory and validated by the validation  body.
Common Criteria certifications are expressed in a seven-step assurance  scale called Evaluation Assurance Levels. The seven ordered levels  provide an increasing measure of confidence in a product’s security  functions. All evaluated products that receive a Common Criteria  certificate appear on a validated products list, which is available on the  Common Criteria Web site.
To facilitate the efficient use of testing resources, an international  agreement was developed under which one country’s Common Criteria  certifications would be recognized by the other participating countries.  This is intended to eliminate unnecessary duplication of testing efforts.
Common Criteria certifications need to be carefully considered. We have  reported previously that the fact that a product appears on the validated  products list does not by itself mean that it is secure. A product’s listing  on any Common Criteria validated products list means that the product  was evaluated against its security claims and that it has met those claims.  The extent to which vendor-certified claims provide sufficient security for  a given application is another question.
section_title: E-passports Have Reasonable Safeguards to Assure That Computer Chip Data Cannot Be Altered or Forged, but Ports of Entry Lack the Capabilities to Use Them
paragraphs: A complex environment has been established to provide reasonable  assurance that the data contained on electronic passports can be used to  help determine whether an individual should be admitted to the United  States. The overall control environment depends on each party effectively  implementing the controls that have been established to govern its  operation and utilize the controls implemented by the other agencies.  State uses a technology commonly referred to as public key cryptography  to generate digital signatures on the data it writes to the computer chips  on the e-passport. These digital signatures, when effectively implemented,  can help provide reasonable assurance that integrity has been maintained  over the data placed on the chip by State. Our review found that DHS has  not implemented the capabilities needed to completely validate the digital  signatures generated by State before relying on the data, which adversely  affects its ability to obtain reasonable assurance that the electronic data  provided in a chip were the same data that State wrote in the e-passport.  While DHS has some controls that somewhat mitigate this weakness, it  does little to ensure that altered or forged electronic data can be detected.  Accordingly, until DHS implements this functionality, it will continue to  lack reasonable assurance that data found on e-passport computer chips  have not been fraudulently altered or counterfeited.
subsections: section_title: State Generates Digital Signatures That Can Be Used to Provide Needed Assurance
paragraphs: ICAO has issued e-passport standards that have been adopted by the  United States and other countries. As part of its specifications for   e-passports, ICAO requires the use of digital signatures and a public key  infrastructure to establish that the data contents of the computer chip are  authentic and have not been changed since being written. A PKI—a system  of hardware, software, policies, and people—is based on a sophisticated  cryptographic technique known as public key cryptography. The use of a  PKI for e-passports primarily serves to provide (1) data integrity (the  electronic data placed on the passport have not been changed), and (2)  authentication (the country issuing the e-passport was the source of the  data). In its standards, ICAO specifies only the use of well-known  cryptographic algorithms for use in e-passports.
As discussed in appendix II, public key cryptography is used to generate  and validate digital signatures. In particular, the “public key” is used to  validate the digital signature that is used to authenticate the data being  signed. However, a means is necessary for the user to reliably associate a  particular public key with a document signer. The binding of a public key  to a document signer is achieved using a digital certificate, which is an  electronic credential that guarantees the association between a public key  and a specific entity.
In agreement with ICAO standards for e-passports, State generates and  writes a digital signature on the chip of each e-passport during the  personalization process. As illustrated in figure 3, State stores the  following information on the e-passport computer chip: biographical  information about the traveler, the traveler’s facial image, and security  data. The biographical data and facial image are organized into data  groups for storage on the e-passport. Each data group is condensed using  a hashing algorithm and the resulting hash values are stored in the security  data. A digital signature is generated on these hash values, which  represent the data stored on the e-passport computer chip. Hence, the  security data on an e-passport consist of three key elements: the data  group hash values, the digital signature, and the certificate needed to  validate the digital signature. This certificate—known as the document  signer certificate—is associated with a digital signature on a U.S.   e-passport’s data and is used to validate that the signed data contained in  that passport were actually generated by State. The keys and certificates  associated with U.S. e-passports are established in a hierarchical manner  to establish a “chain of trust” that a third party, such as DHS, can use to  obtain reasonable assurance that the data contained in the passport are  the data that were actually written on to the e-passport by State.
State has developed a comprehensive set of controls to govern the  operation and management of the PKI that generates the digital signatures  used to help assure the integrity of the passport data written to the chip.  These controls include the development of policies and practices that are  consistent with best practices described in federal guidelines. For  example, State’s policies and procedures for generating and storing digital  signatures and certificates from cryptographic modules minimize the risk  of compromise or unauthorized disclosure. Further, State’s procedures  require the use of cryptographic modules validated against the level 3  criteria of FIPS 140-2, which is consistent with federal best practices and  requirements.
If properly validated, the digital signatures on State’s e-passports should  provide those reading the chip data, including DHS, reasonable assurance  that the data stored on the chip were written by State and have not been  altered. Proper validation includes verifying that the document signer  certificate was issued by the State Department.
section_title: DHS Has Not Implemented the Capability to Fully Verify E-passport Digital Signatures
paragraphs: In July 2007, we reported that DHS was not fully using a key security  feature of the U.S. e-passport—namely the data stored on the chip. At  that time, DHS had not fully deployed e-passport readers to all primary  inspection lanes at all ports of entry and did not have a schedule to do so.  We also reported that the implemented e-passport reader solution was not  capable of validating e-passport digital signatures, which would help to  ensure that the data written to the e-passport chips have not been altered.  Since that time, while DHS has begun planning an acquisition for new   e-passport readers, DHS has made no further deployments of e-passport  readers, nor has it implemented a solution that would allow for the full  verification of the digital signatures on e-passport computer chips.
subsections: section_title: DHS Has Not Fully Deployed E-passport Readers to the Ports of Entry
paragraphs: In 2006, as a part of the United States Visitor and Immigrant Status  Indicator Technology (US-VISIT) system, DHS deployed 237 e-passport  readers at 33 air ports of entry—212 are installed in primary inspection  lanes and 25 are installed in training areas. No e-passport readers are  deployed in secondary inspection areas. While these 33 air ports of entry  were chosen because they process the largest volume of travelers—about  97 percent—from Visa Waiver Program countries, the majority of lanes at  these airports do not have e-passport readers. Even though the same   e-passport readers may be used to read U.S. e-passports, U.S. citizens are  primarily processed through lanes at these air ports of entry that are not  equipped with e-passport readers.
At equipped primary inspection lanes, CBP officers can use e-passport  readers to access the biographical information and digitized photograph  stored on the e-passport chip. To read e-passports, officers place the  biographical page of the e-passport on the reader’s glass plate. The reader  then electronically scans the biographical information printed on the page  and uses it to access the information stored in the e-passport’s chip. Once  the biographical data and photograph from the chip are displayed on the  primary inspection computer screen, the officer is to compare the  information displayed with the information on the biographical page of the  passport and verify that they match. The results of any validation activities  conducted on the data by the system are also presented to the officer. Any  mismatches could indicate fraud.
While a total of 500 e-passport readers were purchased by the US-VISIT  program. DHS has made no further deployments of e-passport readers  since 2006. Those not deployed are in storage, used for training, or used to  support system development activities. Following the deployment at the 33  air ports of entry in 2006, responsibility for deploying the e-passport  readers was shifted from the US-VISIT program to CBP. CBP officials  partially attributed the lack of progress in deploying e-passport readers to  its failure to allocate funding for the activity since it assumed the  responsibility from US-VISIT. According to DHS officials, the slower than  expected times to read data from e-passport chips also influenced its  decisions to not further the deployment of the e-passport readers.
In 2008, DHS transferred $11.4 million of no-year funds from US-VISIT to  CBP for planning, purchasing, and deploying e-passport readers at all CBP  primary processing lanes and secondary inspection areas at the ports of  entry. According to CBP officials, it is currently planning an acquisition for  new e-passport readers. As a part of the acquisition planning, CBP also  expects to determine whether it will replace the 500 currently deployed or  stored e-passport readers with new readers that will likely have better  performance than the current readers. According to DHS, CBP is planning  an e-passport reader procurement that will allow for the full deployment  of e-passport readers in fiscal year 2011.
In our prior work, we recommended that DHS develop a deployment  schedule for providing sufficient e-passport readers to U.S. ports of entry.  With the identification of funding for the effort, CBP has initiated planning  for further deployment of e-passport readers, but has not yet developed a  deployment schedule. Until DHS installs e-passport readers in all  inspection lanes, CBP officers will not be able to take advantage of the  data stored on e-passport chips. For instance, without e-passport readers,  CBP officers are unable to read the photograph and biographic  information stored on the e-passport chip, information that would better  enable officers to detect many forms of passport fraud, including  impostors and the alteration or substitution of the photos and information  printed in the passports, and help to determine the traveler’s identity and  admissibility into the United States.
section_title: DHS Has Not Implemented the Public Key Infrastructure Needed to Verify E-passport Digital Signatures
paragraphs: While DHS’s systems conduct some validation activities to ensure the  integrity of the data on the e-passport chip, it does not have adequate  assurance that the data stored on the chip have not been changed since  they were authored by a legitimate issuing authority—in the case of U.S.   e-passports, the State Department.
In primary inspection lanes that are equipped with e-passport readers,  CBP’s workstations conduct a series of checks using data read from the   e-passport computer chip, including the biographical data, the facial  image, and the security data. First, the CBP workstation verifies that the  biographical data read from the computer chip match that read from the  printed biographical page. Second, the CBP workstation calculates the  hash values of the data groups read from the computer chip and compares  them with the hash values stored in the security data. If available, the CBP  workstation will also use the digital certificate to verify the digital  signature. The expiration date of the e-passport and the digital certificate  are also checked. Finally, if the e-passport has been previously read by  CBP, the hash value of the facial image is compared with the value stored  by CBP. If this is the first time the e-passport has been encountered, the  hash value is stored for future comparisons. Any mismatches are to result  in an error being displayed to the CBP officer.
Further, in October 2008, DHS began to make U.S. passport data available  to CBP officers in primary inspection. DHS is now receiving U.S.-issued  passport data through a datashare initiative with the Department of State.
CBP has modified its workstations to retrieve this additional information  when U.S. passports, including e-passports, are processed. When CBP  officers enter U.S. passport data into appropriately configured CBP  workstations, the photograph of the traveler, as issued by the State  Department, will be displayed to the officer. As e-passports are issued by  State, the corresponding information is made available to DHS through the  datashare. State worked with DHS to transfer data on all valid historical  U.S. passports. As more historical U.S. passport information becomes  available, more photographs will be displayed to primary officers upon  processing a U.S. citizen through primary inspection.
However, the key step that is missing is that the CBP workstation does not  validate the legitimacy of the public key used to verify the digital  signature. Such a validation would provide assurance that the public key  in the document signer certificate was generated by the State Department.  Without this verification, CBP does not have reasonable assurance that the  e-passport data being protected by the digital signature were written by  the State Department because forgers or counterfeiters could simply  generate the keys necessary to digitally sign the forged data and include  their own certificate in the e-passport for verification purposes. Checking  the legitimacy of the certificate containing the public key that is used in  the digital signature validation process would effectively mitigate this risk.
When generated, the document signer certificates are themselves digitally  signed. However, CBP does not have access to the public keys necessary  to validate these digital signatures. While DHS tested the functionality of  storing and using this information to verify the certificates included by  State and other nations on e-passports using the CBP workstation, the  functionality was not implemented for operations because the  infrastructure to collect and maintain the international certificate database  did not exist. According to DHS officials, this function was a US-VISIT  requirement, but did not get implemented, in part, because a DHS  component that would be responsible for operating the public key  database was never identified. DHS officials also stated that the slow  performance of reading e-passports diminished the importance of  implementing this function.
Not being able to check the legitimacy of the document signer certificates  affects not only CBP’s ability to verify the integrity and authenticity of the  data written to U.S. e-passport computer chips, but also its ability to verify  the integrity and authenticity of computer chip data on any country’s   e-passport. The United States requires all 35 participants in the Visa  Waiver Program to issue e-passports, and ICAO has estimated that over 50  countries issue e-passports. Because CBP does not have the necessary  information to fully validate the digital signatures that these countries  generate, it does not have reasonable assurance that data signed by those  countries were actually generated by the authorized passport issuance  agency for that country. Hence, it cannot ensure that the integrity of the  data stored on the e-passport’s computer chip has been maintained.
Two key issues need to be resolved for CBP to be able to rely on data  stored on e-passport computer chips. First, a database needs to be  established and populated with the digital certificates needed to fully  validate the digital signatures that can be accessed by CBP inspection  workstations at the ports of entry. An approach needs to be developed and  implemented to populate the database with the needed information,  including State Department data for U.S. e-passports, that can be used to  fully validate the digital signatures. According to ICAO, this information  should be distributed only through secure diplomatic channels. Second,  CBP needs to develop and implement functionality on its inspection  workstations to access the database when e-passport data are read to  verify that the legitimate passport-issuing authority signed the data being  relied upon. Until these two key issues are addressed, CBP will continue  to lack reasonable assurance that data found on e-passport computer  chips have the necessary integrity; hence, the security enhancements that  could be provided by e-passport computer chip data against counterfeiting  and forgery are not completely realized.
section_title: Malicious Code Does Not Pose a Significant Risk to U.S. E-passport Computer Chips or Federal Computer Systems That Read Them
paragraphs: Protections designed into the U.S. e-passport computer chip limit the risks  of malicious code being resident on the chip, a necessary precondition for  a malicious code attack to occur from the chip against computer systems  that read them. GPO and State have taken additional actions to decrease  the likelihood that malicious code could be introduced onto the chip.  While these steps do not provide complete assurance that the chips are  free from malicious code, the limited communications between the   e-passport chip and agency computers significantly lowers the risk that  malicious code—if resident on an e-passport chip—could pose to agency  computers. As we previously discussed, the e-passport’s digital signature  can provide reasonable identification of unauthorized modification of the  user data areas—including modifications resulting from the introduction  of malicious code. Finally, given that no protection can be considered  foolproof, DHS still needs to address deficiencies noted in our previous  work on the US-VISIT computer systems to mitigate the impact of  malicious code, should it infect those systems.
subsections: section_title: U.S. E-passport Chip Designs and Manufacturing Processes Limit Exposure to Malicious Code
paragraphs: Security features designed into the e-passport computer chips, including  the digital signature, provide protections against the introduction of  malicious code onto the chip during the e-passport booklet production  process. For example, among other features, the chips include physical  tamper protections that aid in sensing or thwarting physical attacks, a  cryptographic authentication procedure to lock the contactless interface  against unauthorized access, and incorporation of a digital signature that  can be used to identify any unauthorized modification of the user data  areas.
subsections: section_title: Physical Tamper Protections Help Ensure against Physical Attacks on the Chip
paragraphs: As of 2007, NIST had not been able to identify any known cases of a  malicious code attack against a computer network from a contactless  chip. Nevertheless, both NIST and DHS agree that it is possible and have  generally identified physical tamper attacks as threats to embedded  electronic chips in contactless applications such as e-passports.
Physical tamper attacks involve stripping away the chip’s outer coverings,  exposing the electronic circuitry on the wafer, and analyzing or monitoring  chip activity by inserting electronic probes onto components etched into  the wafer. In general, the aim of such an attack is to discover confidential  data stored on the chip—such as cryptographic keys—which can be used  to open access to the chip via the contactless interface. In terms of a  malicious code threat, the purpose then would be to write malicious code  onto the chip via the RF interface.
In its guide to chip-level security for contactless ICs, DHS identifies  common methods used in physical tamper attacks on contactless ICs. For  example, after removing top layers of plastic or other coverings and  uncovering the electrical surfaces of the chip, attackers could probe into  the various chip layers in an attempt to understand its processing.  Common methods of physical attack are those related to (1) fault  introduction, (2) IC monitoring, and (3) reverse engineering. The purpose  of each of these attacks is ultimately to uncover secret information—such  as cryptographic keys or passwords—that would allow an attacker to  open the chip for read/write access via the contactless interface. In fault  introduction, attackers attempt to introduce faults randomly, at specific  times during the processing, or in specific locations on the IC circuitry, to  gain additional information about the chip processing during such faults,  which could provide clues to the memory location of secret keys.  Similarly, such clues can be uncovered using IC monitoring, where readers  or probes placed on the chip’s internal circuitry are used to monitor  calculations or flows of data on the chip. Finally, attackers could attempt  to reverse engineer the computer chip to decipher its hardware  architecture and read the secret information.
In its guide, DHS identifies countermeasures for each of these types of  attack. For example, protections against fault introduction include  implementing sensors that detect when parameters, such as light or  temperature, vary outside of expected values. If such variations are  sensed, the chip may automatically reset or even disable itself. Protections  against IC monitoring might include encrypting the traffic flowing along  the internal circuitry so that interpretation would be difficult. Protections  against physical analysis include encrypting information stored in memory  and scrambling the design of the logic contained in the operating system  when laid down in memory during IC creation. Well-designed security  microcontrollers, with numerous security features and support for mutual  authentication and sophisticated cryptographic functions, can be designed  to make it extremely difficult, costly, and time-consuming for attackers to  compromise.
In its solicitation for the e-passport covers, which included the computer  chips, GPO specified several hardware and software requirements to  protect against physical attack, including specific features to assist in  protection against power and timing attacks. It also included requirements  for sensors to monitor, for example, temperature and voltage variations,  which might be indicative of a physical tamper attack. The chips used in  the U.S. e-passports are considered security microcontrollers designed for  applications where security is an important consideration, such as  payment, identity, and secure access and, as such, they incorporate several  features against physical tamper attacks. Both types of chips used in the   e-passports have incorporated some recommended countermeasures for  all of the common categories of attack identified by DHS. For example, the  chips incorporate temperature and light sensors to monitor when those  operating conditions vary from expected values and employ memory  encryption against reverse engineering of the chip .
While it is not possible to provide complete protection against the more  invasive physical attacks, the goal is to make the cost of mounting such an  attack prohibitive. While the threat of physical attack to the embedded  chips in the e-passport cannot be completely discounted, the security  features incorporated into the microcontrollers in U.S. e-passports make a  physical tamper attack impractical.
section_title: Cryptographic-Based Authentication Procedures Control Contactless Access to the Chip during Booklet Production
paragraphs: During production of the e-passport covers, the manufacturers, their  subcontractors, and at GPO and State—or anywhere en route between  these sites—the chips are protected from unauthorized access through the  contactless interface by authentication procedures based on cryptography.
The manufacturing and personalization process for the e-passport booklet  is complex and involves many handoffs between different sites,  companies, and sometimes different countries. For example, while both   e-passport cover contractors originate chip manufacturing in Europe, they  also send the chips to various third-party companies in Asia for additional  manufacturing steps. The overall process can take almost 2 years from the  time the chip leaves the fabrication plant until it is finally issued by the  State Department to a bearer as part of an e-passport.
During the production life cycle of the e-passport book—from chip  creation at the chip manufacturers through to personalization by State— contactless access to the chip is controlled by a symmetric cryptography  authentication procedure. Cryptographic algorithms provide different  measures of strength, depending on the algorithm and the overall length of  the keys involved. According to NIST estimates, the version used on the   e-passports can, at best, provide protection from a brute force attack until  2030.
This locking mechanism not only controls access to the chip, but  differentially allows only certain functions to be performed.
section_title: Other Design and Manufacturing Steps Help Mitigate the Risk from Malicious Code
paragraphs: Several other design features limit the chance that malicious code could  be placed on the chip. For example, according to GPO, an additional step  used to protect the e-passport chips from unauthorized access during the  manufacturing process takes advantage of standard industry practice to  not include customer identification with chips during production runs.  During the chip-manufacturing process, an anonymous cataloging scheme  is employed that makes it difficult to associate bulk lots of chips with their  destined applications. Therefore, on the production floor, it cannot be  determined which chips are to be used in U.S. e-passports.
In addition, after the chips are manufactured and incorporated into the   e-passport cover, steps are taken by GPO and State to protect the user  data areas of the chip from tampering. First, as part of its formatting  procedures to prepare the chips for personalization, GPO ensures that the  user data area is free from any data—including malicious code. During the  formatting of the user data area, if any memory cell is found to be  defective, then GPO discards the e-passport booklet. Therefore, any  malicious code successfully implanted within the user data area after  manufacture and through any of the chip’s travels through its production  cycle up until it arrived at GPO would be erased from the chip.
As we previously discussed, during the e-passport personalization process,  a digital signature is applied to the data to help assure the integrity and  authenticity of the data written to the chip. One of the benefits of the  digital signature is that any insertion of malicious code into, for example,  the bearer’s digital image would be caught, provided the digital signature  is fully and properly verified. Such a successful check would provide  reasonable assurance that malicious code has not been inserted into the  user data areas of the chip memory since it was personalized by State.
section_title: Limited Communications between the E-passport Chip and Agency Computers and Security Certifications and Reviews Mitigate Risks Posed by Malicious Code
paragraphs: GPO and State have taken steps to gain confidence that their e-passport  computer chips are secure. While these steps do not provide complete  assurance that the chips are free from malicious code, the limited  communications between the e-passport chip and agency computers  significantly lowers the risk that malicious code that could be resident on  an e-passport chip could pose to agency computers. The chips have been  tested for both interoperability and conformance to ICAO specifications  and exercised by GPO as part of their formatting process. The chips have  undergone a formal, independent process to validate some aspects of their  security. GPO and State also periodically conduct security reviews of the  chip manufacturer sites.
subsections: section_title: Controls on the Interface between the E-passport Computer Chip and Agency Computers Limit the Opportunities for Transfer of Malicious Code
paragraphs: One key feature that mitigates the risk that malicious code on the chip  could pose to agency computers is the highly restricted nature of the data  exchange between the chip and agency computers during the reading of  the e-passport. The e-passport computer chip adheres to ISO 14443 and  ISO 7816-4 for communications through the contactless interface. The  standards restrict the computer chip to a slave role whereby it responds  only to a specific set of commands with known and limited response data.  Because the chip cannot independently initiate communication with a  reader, the flow of data from the chip to the reader and host computer can  be precisely controlled and limited to only what is expected by the host  computer.
The result is that opportunities for the covert embedding of malicious  code within data transferred from the chip to agency computers are  correspondingly limited. For example, the passport number, bearer’s  name, and date of birth are data sets restricted to a well-defined set of  characters and are of fixed length. Consequently, if a reader accepts inputs  only within these bounds, it will limit the risk posed by malicious code.  The digital image of the bearer is the only data set transferred that is of  enough size to provide for opportunities to hide malicious code. The image  is formatted according to a standard graphics format that facilitates  integrity checking of its contents. According to DHS officials, when   e-passports are read, the data from the chip are verified both by the   e-passport reader as well as by the agency host computer before the data  are processed.
Testing Helps to Verify Proper Functioning of E-passport Chip  Communications  Prior to contract award, and at various points thereafter, the U.S.   e-passport chips have undergone testing for a variety of purposes.
According to GPO officials, the solicitation for the e-passport covers was  based on State Department requirements for specific functionality,  security, performance, and availability. For example, it included  requirements for the chip to meet ISO 14443 communications and ISO  7816-4 command set standards and other standard specifications. As part  of the award selection process, GPO, State, NIST, and NSA conducted  testing of sample books from each bidder to determine whether they  would meet requirements as specified in the request for proposal.
During pre-award testing, for example, GPO ran initial tests to ensure  basic functionality as specified by ISO 7816-4, including the ability to  initialize, read, write, and lock the chip. GPO also ensured that each   e-passport cover was of the correct form and thickness so that it could  mechanically pass through its production equipment suite. The sample  booklets then went to State, which conducted tests to ensure the books  could work with its personalization systems.
According to NIST officials, they performed electronic testing that looked  at the potential for eavesdropping, jamming, and remote activation  (skimming). For eavesdropping, the test was conducted to determine  whether the legitimate communication could be intercepted, but no  attempt was made to see if the encrypted communication could be  understood. For jamming, the purpose was to determine whether  legitimate communications with the chip could be prevented. For remote  activation, the purpose was to determine the distance from which a reader  could elicit a response from the chip, but no attempt was made to test the  basic access control or to read the data on the chip. NIST also conducted  different types of durability tests including static bend, dynamic bend,  climate, chemical resistance, physical protection of the integrated circuit  chip, and electromagnetic testing. None of NIST’s tests were designed to  test for the presence of malicious code on the chip. While the tests  exercised some portions of ISO 14443 and ISO 7816-4, NIST did not  conduct any tests to ensure full conformance with these standards.
NSA officials stated that they conducted electronic testing of the booklet,  but this was confined to radio frequency testing and shielding testing  specifically tasked by GPO to evaluate the susceptibility of the booklet to  skimming by looking at the distance over which the booklet’s chip could  become energized. NSA performed no substantive tests of communication  with the chip and no testing at all with regard to malicious code.
As part of GPO’s normal pre-personalization processing, GPO exercises  and tests each chip’s functionality to verify, among other things, the  correct reading and writing of every chip. GPO’s processing does not  systematically exercise every chip function or the full ISO 7816-4  command set and associated error handling. GPO officials said that while  they test the basic functionality of the chip as they proceed through the  pre-personalization processing, full ISO 14443 communications and ISO  7816-4 command set processing—including ensuring that all error  handling is performed correctly—is done as part of the international ICAO  interoperability and conformance tests held approximately every 2 years.  The State Department is the official U.S. representative to these tests,  although GPO frequently participates, by request, in support of State.  According to ICAO, the interoperability and conformance tests are  intended to accomplish two things. First, they ensure that e-passports  from different countries can be read by readers provided by multiple  vendors. Second, they ensure compliance with various aspects of the ISO  14443 communication and ISO 7816-4 command set standards. The U.S   e-passport chips have been part of some of the interoperability and  conformance tests that have been run in the last several years.
All these tests provide important assurances for their stated purposes by  exercising functionality, in particular the limited e-passport chip  communications, that helps to protect against the risk of malicious code.  In general though, such testing is limited to verifying functionality and  cannot provide absolute assurance that malicious code has not been  implanted onto the e-passport computer chip.
section_title: Security Certifications and Security Reviews Provide Some Assurance That Computer Chips Are Free from Malicious Code
paragraphs: The creation of the computer chip used in U.S. e-passports is a complex  process that involves many components created by different entities.  Because the U.S. government does not control the entire supply chain for  all the components on the chip, it relies on security features provided by  the chip component suppliers, the extent to which these suppliers test and  certify their products, and the extent to which these suppliers develop and  produce the chips in a secure manner.
Some Aspects of the Security of the Chips Were Certified Using  Common Criteria  NIST guidelines state that federal agencies should give substantial  consideration in IT procurements to products that have been evaluated  and tested by accredited laboratories against appropriate security  specifications and requirements. One established mechanism for  providing security evaluation and testing services for commercial-off-the- shelf hardware, software, or firmware is Common Criteria. Common  Criteria certifications are a well-known international standard mechanism  for validating and documenting various security aspects of IT products.  Evaluations are performed by accredited Common Criteria testing  laboratories whose results are then certified by a validation body. In the  case of the chips used in the U.S. e-passports, selected security features of  their hardware components were evaluated using Common Criteria by a  recognized European laboratory and certified by Germany’s Common  Criteria certification body.
In its solicitation for the e-passport covers, including the computer chips,  GPO specified that preference will be given to computer chips that are  certified at Common Criteria EAL 4+ against a Common Criteria-compliant  Protection Profile. According to Common Criteria definitions, an EAL 4  rating is intended to provide a moderate to high level of independently  assured security. To achieve this rating, the testing lab must conduct a  variety of structured activities, including an analysis of the security  functions of the product using a complete interface specification and both  the high-level and low-level design of the specific features of the product  being tested, review and confirmation of any vendor testing that was  conducted, and conduct of an independent vulnerability analysis  demonstrating resistance to penetration attackers with a low attack  potential.
The computer chips selected for use in the e-passports each had received  an EAL 5+ rating against a compliant Protection Profile. According to  Common Criteria, an EAL 5 rating incorporates all of the EAL 4  requirements and, in addition, requires, among other things, semiformal  design descriptions, a more structured architecture, covert channel  analysis, and improved mechanisms that provide confidence that the  particular implementation of the product being evaluated has not been  tampered with during development. Specific security features evaluated to  achieve the EAL 5 rating include many useful in helping to prevent the  introduction of malicious code. Examples of these include support for  cryptographic functions, protections against physical manipulation, and  features to ensure correct operating conditions for the chip.
However, a key software component of the chip—the operating system— was excluded from the evaluation. The operating system on the chip  implements and controls, among other functions, the ISO 7816-4 command  set that is the primary means of communication between the chip and the  outside world—including agency computers.
Under Common Criteria, it is not uncommon for critical components of a  product to be excluded for particular evaluations. In particular, the  exclusion of important software components, such as the operating  system, from the Common Criteria evaluation of hardware features is not  unusual because the higher-level software embedded on chips is often a  third-party product and not designed by the chip manufacturer itself. The  chip manufacturer is typically not responsible for undertaking a Common  Criteria evaluation of third-party embedded software used on its chips.  Typically, it would be up to the software provider to get its product  certified using Common Criteria. However, this is an expensive and time- consuming process. Hence, care needs to be taken with Common Criteria  certifications that can be meaningfully understood only within the context  of the specific subset of security functions included in the evaluation.
We have previously noted that one of the challenges in using the National  Information Assurance Partnership is the difficulty in matching agencies’  needs with the availability of NIAP-evaluated products. According to  Infineon and Gemalto officials, back in 2006 when the request for proposal  for the e-passport covers was issued, there was no Protection Profile  available that covered the operating systems of such chips. Since that  time, however, Common Criteria operating systems suitable for use on  smart cards have become available. According to GPO officials, Infineon  provides such chips today, and GPO is in the process of transitioning them  into production so that, at least for the Infineon line, the e-passports will  include a Common Criteria-certified operating system.
The user operating system contains arguably most of the software  functioning on the chip. Therefore, obtaining assurance as to its secure  functioning and freedom from malicious code is an important activity.  However, given the highly restricted nature of the current communications  between the chip and agency computers, we do not see the lack of  Common Criteria certification of the chip operating system as significantly  increasing the risk to agency computers from malicious code.
While Common Criteria certification confers some assurance regarding the  specific security functions included in the evaluation, care must be taken  in extending that assurance into confidence in the overall security of the  product for its intended use. GAO has previously reported that within its  limitations, the Common Criteria process provides benefits. However, the  lack of performance measures leaves questions unanswered as to its true  effectiveness. The use of commercial products that have been  independently tested and evaluated is only a part of a security solution  that contributes to the overall information assurance of a product.
GPO Has Conducted Reviews of the E-passport Computer Chip  Manufacturing Sites  Prior to contract award, and periodically thereafter, GPO—sometimes  accompanied by the State Department—conducted on-site security  reviews of the companies that manufacture the e-passport chips and the  covers, and of some of their subcontractors. According to GPO officials,  its reviews are concerned with not just security risks, but also with other  risks—for example, the extent to which a site performs continuity of  operations planning or the risk that a single source of supply for one of the  components might pose a risk to the delivery of the components. In  conducting the security reviews, GPO officials stated that they make an  attempt to visit every vendor involved in the production of the e-passport  booklet, including, for example, the security ink suppliers, paper  providers, thread providers, and the chip providers. The sites are spread  across several countries, and within some countries there may be multiple  sites. For example, for both Infineon and Gemalto, production of the chips  involves several sites within Europe.
These reviews employ an American National Standards Institute (ANSI)  standard for security product manufacturing that covers a variety of risk  areas, including information, IT, material, supply chain, physical intrusion,  personnel, and disaster recovery. For example, the standard addresses  such concerns as proper controlled access to restricted areas within a  facility. During the security review, GPO generally gets a high-level  briefing from the company and talks with staff at the site. According to  GPO officials, they have reviewed almost every site twice since March  2006. In recent security reviews of the chip manufacturing sites, both  Infineon and NXP were found to be in compliance with their own stated  security policies and meeting the Class 1 level of the ANSI standard.
From the security reviews, GPO can get some sense of some of the  protections in place at the development sites—for example, access control  to development areas and security awareness training. GPO learned  through its reviews, for example, that Gemalto has an access control  policy wherein development premises are divided into secure and  nonsecure zones, and the operating system development is in the secured  zone. This provides some assurance that since physical access to the  software destined for the chips is controlled, opportunities for the  inclusion of malicious code can be limited.
section_title: To Further Mitigate the Effect of a Malicious Code Attack, DHS Needs to Address Previously Noted Weaknesses in US-VISIT Computer Systems
paragraphs: Given that there can be no guarantees against a malicious code attack  originating from the e-passport computer chip, agency systems need to  have a strong security posture, in accordance with federal government  standards. We have previously reported on weaknesses in DHS’s US-VISIT  computer systems, which could increase the ability of malicious code to  infect and propagate through agency computers. Weaknesses, such as  unpatched software vulnerabilities, can invite a malicious code attack and  enhance the ability of the attack to spread across the network by leaving  important linkages within the network unprotected. DHS needs to address  these deficiencies to ensure that any malicious code resident on the   e-passport chip and read onto DHS computers can be contained and its  effect minimized.
One of the strong recommendations from NIST is that computer systems  run antivirus software, which scans systems’ files and memory spaces for  known malware. NIST strongly recommends the use of antivirus software  to identify and protect against malicious code. Detecting such code prior  to its further spread can limit a malicious code infection and protect  downstream systems. According to DHS officials, workstations that  control the interface with the chip are protected by antivirus software,  which includes access protections, buffer overflow protections, and  scanning of files as they are accessed.
One of the key weaknesses in US-VISIT that we found in 2007—patch  management—is of particular concern with respect to malicious code that  could be read from an e-passport. Malicious code often attacks systems by  exploiting vulnerabilities in operating systems, services, and applications.  When software vulnerabilities are discovered, the software vendor may  develop and distribute a patch or workaround to mitigate the vulnerability.  Patch management is, therefore, an important element in mitigating the  risks associated with malicious code and the vulnerabilities they depend  on. NIST’s, NSA’s, and DHS’s own policies stress the importance of  keeping computer systems up to date with security patches. Outdated and  unsupported software is more vulnerable to attacks and exploitation. NIST  guidelines state that applying patches is one of the most effective ways of  reducing the risk of malware incidents.
In our prior report, we noted that while DHS has taken steps to ensure that  patches for the workstations’ operating system were kept up to date, some  workstations at the ports of entry did not consistently maintain secure  configurations. As a result, vulnerabilities left unpatched on those systems  increase the chance of malicious code being executed should it get  ingested. According to DHS officials, they are in the midst of upgrading  workstations to a version of Microsoft Windows that contains features to  help prevent the execution of malicious code—for example, special  services to detect and prevent the execution of code from the data areas.  DHS needs to ensure that it completes the upgrade of the workstations  and that such services are enabled on workstations reading data from the  e-passport computer chips.
section_title: Conclusions
paragraphs: Ensuring the integrity of passports requires continual vigilance so that  they can continue to be used to support the critical border security  mission—facilitating the travel of those who are entitled to enter the  United States while preventing the entry of those who are not. A well- designed passport has limited utility if it is not well produced or border  officers do not utilize the available security features to detect attempts to  fraudulently enter the United States. While U.S. e-passport covers,  including the embedded computer chip, are manufactured by foreign  companies, State’s public key infrastructure, which is used to generate  digital signatures during the personalization process for each issued  passport, can provide reasonable assurance that the data written onto the  chip were authored by State and have not been altered. However, DHS has  not implemented the capabilities needed for CBP officers to fully utilize  this security feature. Without e-passport readers at the ports of entry or a  system that allows for the full validation of digital signatures on   e-passports, CBP officers’ inspection of not only U.S. e-passports, but also  of e-passports issued by foreign countries, including those participating in  the visa waiver program, is affected. Without these capabilities, the  additional security against forgery and counterfeiting that could be  provided by the inclusion of computer chips on e-passports issued by the  United States and foreign countries, including those participating in the  visa waiver program, is not fully realized.
While the use of e-passports and radio frequency communications  represents another potential attack vector to federal computer systems,  the risk posed by the transmission of malicious code on U.S. e-passports is  not significant. The U.S. e-passport chips have security features that  minimize the threat of tampering during the manufacturing and production  process. GPO and State have also taken steps to assure the security of the  embedded computer chips in U.S. e-passports. Because the  communications between e-passport computer chips and federal  computer systems have been designed to be limited, the opportunities for  transfer of malicious code are correspondingly limited. Combined, these  measures significantly reduce the risks from someone using e-passport  computer chips as a conveyance for malicious code to federal computer  systems.
section_title: Recommendations for Executive Action
paragraphs: To ensure that border officers can more fully utilize the security features  of electronic passports, we recommend that the Secretary of Homeland  Security take the following two actions to provide greater assurance that  electronic passport data were written by the issuing nation and have not  been altered or forged:    Design and implement the systems functionality and databases needed to  fully verify electronic passport digital signatures at U.S. ports of entry.
In coordination with the Secretary of State, develop and implement an  approach to obtain the digital certificates necessary to validate the digital  signatures on U.S. and other nations’ electronic passports.
section_title: Agency Comments and Our Evaluation
paragraphs: We provided draft copies of this report to the Secretaries of State and  Homeland Security and to the Public Printer at the Government Printing  Office for review and comment. We received formal written comments  from the Department of Homeland Security, which are reprinted in  appendix III. In its comments, DHS concurred with our recommendations.  However, DHS believes that the report incorrectly portrays CBP’s ability  to detect the fraudulent use of U.S. passports. DHS cites the ability of  CBP’s officers to access U.S. passport application data from State and use  it to detect impostors and altered data in U.S. passports. We agree that  providing State passport data to CBP officers during the inspection  process enhances their ability to detect the fraudulent use of U.S.   e-passports. Nevertheless, while State has expended significant resources  to produce an e-passport that includes contactless chip technology and  public key cryptography to help prevent counterfeiting and forgery, DHS  has not implemented the capabilities to fully utilize these security features  and is not fully realizing the security benefits of the inclusion of electronic  technology on e-passports.
We received informal comments from the State Department. State believes  that the draft report presents a comprehensive and balanced assessment  of the security of the e-passport design. We also received technical  comments from State, GPO, and DHS, which we incorporated in the  report, as appropriate.
As we agreed with your offices, unless you publicly announce the contents  of this report earlier, we plan no further distribution of it until 30 days  from the report date. At that time, we will send copies of this report to the  Secretaries of State and Homeland Security and the Public Printer. In  addition, the report will be available at no charge on the GAO Web site at  http://www.gao.gov.
If you or your staff have any questions about this report, please contact me  at (202) 512-4499 or barkakatin@gao.gov. Contact points for our Offices of  Congressional Relations and Public Affairs may be found on the last page  of this report. GAO staff who made major contributions to this report are  listed in appendix IV.
section_title: Appendix I: Scope and Methodology
paragraphs: To determine whether e-passport chips can be altered or forged so that a  traveler could fraudulently enter the United States, we interviewed  officials from State’s Bureau of Consular Affairs and reviewed State  Department policies, procedures, and guidance documents regarding the  public key infrastructure (PKI) used to protect the data on the e-passport  computer chip and assessed them against relevant International Civil  Aviation Organization (ICAO) and National Institute of Standards and  Technology (NIST) standards and guidelines. We interviewed officials at  one passport issuance agency and reviewed systems documentation to  understand how U.S. e-passports are personalized. We determined the  extent to which U.S. e-passport computer chips are inspected at U.S. ports  of entry by interviewing Department of Homeland Security (DHS) officials  and reviewing documentation regarding the systems and procedures used  to inspect e-passports at the ports of entry. Within DHS, we met with  officials from the U.S Customs and Border Protection (CBP), the  Screening Coordination Office, and the United States Visitor and  Immigrant Status Indicator Technology (US-VISIT) program office.
To determine whether malicious code on the e-passport chips poses a risk  to national security, we determined how U.S. e-passport computer chips  are manufactured and incorporated into the production of blank U.S.   e-passport booklets based on interviews with the Government Printing  Office (GPO) and manufacturer officials and our reviews of GPO  documentation. We met with officials from NIST and the National  Counterterrorism Center to determine the level of threat that exists to U.S.  e-passports. We interviewed GPO and State officials and reviewed  documentation that describes the U.S. e-passport computer chip  architecture and operations. We reviewed documents governing the  manufacturing of the blank e-passport covers, including GPO contracts  with the manufacturers and the memorandum of understanding between  GPO and State. We determined that for malicious code on the e-passport  computer chip to be a risk to agency computers, it must first get on the  chip, then get transferred off the chip and onto agency computers, and  then subsequently get executed. Therefore, we identified and evaluated  protections that have been designed into the e-passport computer chip to  reduce the possibility of malicious code being introduced onto the chip,  controls in place to limit the transfer of malicious code off of the chip and  onto agency computers, and the security posture of the agency computer  systems interfacing with the e-passport chip. We also reviewed the results  of testing conducted on the e-passport computer chips by GPO, NIST, the  National Security Agency, and ICAO, and through the Common Criteria  program. We discussed and reviewed the results of security reviews  conducted by GPO. We met with GPO, State, and CBP officials to  understand how each agency interacts with the e-passport computer chips  and the potential risk that malicious code could pose to these agencies.
We conducted this performance audit from June 2008 to January 2010 in  accordance with generally accepted government auditing standards. Those  standards require that we plan and perform the audit to obtain sufficient,  appropriate evidence to provide a reasonable basis for our findings and  conclusions based on our audit objectives. We believe that the evidence  obtained provides a reasonable basis for our findings and conclusions  based on our audit objectives.
section_title: Appendix II: Digital Signatures and Public Key Cryptography
paragraphs: Cryptography is the transformation of ordinary data (commonly referred  to as plaintext) into a code form (ciphertext) and back into plaintext using  a special value known as a key and a mathematical process called an  algorithm. Cryptography can be used on data to (1) hide their information  content, (2) prevent their undetected modification, and/or (3) prevent their  unauthorized use. A basic premise in cryptography is that good systems  depend only on the secrecy of the key used to perform the operations  rather than on any attempt to keep the algorithm secret. The algorithms  used to perform most cryptographic operations over the Internet are well  known; however, because the keys used by these algorithms are kept  secret, the process is considered secure.
The basis of PKI’s security assurances is a sophisticated cryptographic  technique known as public key cryptography, which employs algorithms  designed so that the key that is used to encrypt plaintext cannot be  calculated from the key that is used to decrypt the ciphertext. These two  keys complement each other in such a way that when one key is used for  encryption, only the other key can decrypt the ciphertext. One of these  keys is kept private and is known as the private key, while the other key is  widely published and is referred to as the public key. When used as shown  in figure 4, public key cryptography can help to assure data confidentiality  because only the private key can be used to decrypt the information  encrypted using the public key. When used as shown in figure 5, public key  cryptography can help provide authentication, nonrepudiation, and data  integrity because the public key will only work to decrypt the information  if it was encrypted using the private key. In both cases, ensuring the  security of the private key is vital to providing the necessary security  protections. If the private key is compromised, there can be little  assurance that data confidentiality, authentication, and data integrity can  be provided by the PKI.
Cryptographic techniques are used to generate and manage the key pairs  (a public key and private key), which are in turn used to create electronic  “certificates,” which link an individual or entity, such as State, to its public  key. These certificates are then used to verify digital signatures (providing  authentication and data integrity).
subsections: section_title: Creating and Using Digital Signatures
paragraphs: Public key cryptography can be used to create a digital signature for a  message or transaction, thereby providing authentication, data integrity,  and nonrepudiation. For example, if Bob wishes to digitally sign an  electronic document, he can use his private key to encrypt it. His public  key is freely available, so anyone with access to his public key can decrypt  the document. Although this seems backward because anyone can rea what is encrypted, the fact that Bob’s private key is held only by Bob  provides the basis for Bob’s digital signature. If Alice can successfully  decrypt the document using Bob’s public key, then she knows that the  message came from Bob because only he has access to the corresponding  private key. Of course, this assumes that (1) Bob has sole control ov er his  private signing key and (2) Alice is sure that the validate Bob’s messages really belongs to Bob.
Digital signature systems use a two-step process, as shown in figure 6.  First, a hash algorithm is used to condense the data into a message digest.  First, a hash algorithm is used to condense the data into a message digest.  Second, the message digest is encrypted using Bob’s private signing key to  Second, the message digest is encrypted using Bob’s private signing key to  create a digital signature. Because the message digest will be different for  create a digital signature. Because the message digest will be different for  each signature, each signature will also be unique, and using a good hash  each signature, each signature will also be unique, and using a good hash  algorithm, it is computationally infeasible to find another message that will  algorithm, it is computationally infeasible to find another message that will  generate the same message digest.  generate the same message digest.
Alice (or anyone wishing to verify the document) can compute the  message digest of the document and decrypt the signature using Bob’s  public key, as shown in figure 7. Assuming that the message digests matc Alice then has three kinds of security assurance. First, that Bob actu ally  h,  signed the document (authentication). Second, the digital signature  ensures that Bob in fact sent the message (nonrepudiation). And third,  because the message digest would have changed if anything in the  message had been modified, Alice knows that no one tampered with the  contents of the document after Bob signed it (data integrity). Again, this Again, thisassumes that (1) Bob has sole control over his private signing key and   assumes that (1) Bob has sole control over his private signing key and   (2) Alice is sure t (2) Alice is sure that the public key used to validate Bob’s messages really  belongs to Bob. hat the public key used to validate Bob’s messages really  belongs to Bob.
section_title: Digital Certificates and Certification Authoritie Link Public Keys with Specific Users to Trust
paragraphs: A digital certificate is an electronic credential that guarantees the  association between a public key and a specific entity. It is created  placing the entity’s name, the entity’s public key, and certain other  identifying information in a s directory or other database.  mall electronic document that is stored in a  Directories may be publicly available repositories kept on servers that act like telephone books for users to look up others’ public keys. The digital  certificate itself is created by a trusted third party called a certification  authority, which digitally signs the certificate, thus providing assurance  that the public key contained in the certificate does indeed belong to the  individual or organization named in the certificate. A certification  authority is responsible for managing digital certificates. The purpos the certification authority is to oversee the generation, distribut ion,  renewal, revocation, and suspension of digital certificates. The  certification authority may set restrictions on a certificate, such as the  starting date for which the certificate is valid as well as its expira It is at times necessary to revoke digital certificates before their  established expiration dates, for example, when the private key is  compromised. Therefore, the certification authority is also responsible providing certificate status information and may publish a certificat revocation list in a directory or maintain an online status-checking  mechanism. The PKI software in the user’s computer can verify that the  certificate is valid by first verifying that the certificate has no then by assuring that it has not been revoked or suspended.
section_title: Appendix III: Comments from the Department of Homeland Security
section_title: Appendix IV: Contact and Staff Acknowledgments
subsections: section_title: GAO Contact
section_title: Staff Acknowledgments
paragraphs: In addition to the contact named above, William Carrigg, Richard Hung,  and John C. Martin made key contributions to this report.