The product does not encrypt sensitive or critical information before storage or transmission.

Primary

Architecture and Design
OMISSION: This weakness is caused by missing a security tactic during the architecture and design phase.

Operation

High

Confidentiality
Read Application Data
If the application does not use a secure channel, such as SSL, to exchange sensitive information, it is possible for an attacker with access to the network traffic to sniff packets from the connection and uncover the data. This attack is not technically difficult, but does require physical access to some portion of the network over which the sensitive data travels. This access is usually somewhere near where the user is connected to the network (such as a colleague on the company network) but can be anywhere along the path from the user to the end server.

Confidentiality
Integrity
Modify Application Data
Omitting the use of encryption in any program which transfers data over a network of any kind should be considered on par with delivering the data sent to each user on the local networks of both the sender and receiver. Worse, this omission allows for the injection of data into a stream of communication between two parties -- with no means for the victims to separate valid data from invalid. In this day of widespread network attacks and password collection sniffers, it is an unnecessary risk to omit encryption from the design of any system which might benefit from it.

Manual Analysis
The characterizaton of sensitive data often requires domain-specific understanding, so manual methods are useful. However, manual efforts might not achieve desired code coverage within limited time constraints. Black box methods may produce artifacts (e.g. stored data or unencrypted network transfer) that require manual evaluation.
High

Automated Analysis
Automated measurement of the entropy of an input/output source may indicate the use or lack of encryption, but human analysis is still required to distinguish intentionally-unencrypted data (e.g. metadata) from sensitive data.

Manual Static Analysis - Binary or Bytecode

According to SOAR [REF-1479], the following detection techniques may be useful:

Cost effective for partial coverage:

Binary / Bytecode disassembler - then use manual analysis for vulnerabilities & anomalies

SOAR Partial

Dynamic Analysis with Automated Results Interpretation

According to SOAR [REF-1479], the following detection techniques may be useful:

Cost effective for partial coverage:

Web Application Scanner
Web Services Scanner
Database Scanners

SOAR Partial

Dynamic Analysis with Manual Results Interpretation

According to SOAR [REF-1479], the following detection techniques may be useful:

Highly cost effective:

Network Sniffer

Cost effective for partial coverage:

Fuzz Tester
Framework-based Fuzzer
Automated Monitored Execution
Man-in-the-middle attack tool

High

Manual Static Analysis - Source Code

According to SOAR [REF-1479], the following detection techniques may be useful:

Highly cost effective:

Focused Manual Spotcheck - Focused manual analysis of source
Manual Source Code Review (not inspections)

High

Automated Static Analysis - Source Code

According to SOAR [REF-1479], the following detection techniques may be useful:

Cost effective for partial coverage:

Context-configured Source Code Weakness Analyzer

SOAR Partial

Architecture or Design Review

According to SOAR [REF-1479], the following detection techniques may be useful:

Highly cost effective:

Inspection (IEEE 1028 standard) (can apply to requirements, design, source code, etc.)
Formal Methods / Correct-By-Construction

Cost effective for partial coverage:

Attack Modeling

High

Requirements
Clearly specify which data or resources are valuable enough that they should be protected by encryption. Require that any transmission or storage of this data/resource should use well-vetted encryption algorithms.

Architecture and Design

Ensure that encryption is properly integrated into the system design, including but not necessarily limited to:

Encryption that is needed to store or transmit private data of the users of the system
Encryption that is needed to protect the system itself from unauthorized disclosure or tampering

Identify the separate needs and contexts for encryption:

One-way (i.e., only the user or recipient needs to have the key). This can be achieved using public key cryptography, or other techniques in which the encrypting party (i.e., the product) does not need to have access to a private key.
Two-way (i.e., the encryption can be automatically performed on behalf of a user, but the key must be available so that the plaintext can be automatically recoverable by that user). This requires storage of the private key in a format that is recoverable only by the user (or perhaps by the operating system) in a way that cannot be recovered by others.

Using threat modeling or other techniques, assume that data can be compromised through a separate vulnerability or weakness, and determine where encryption will be most effective. Ensure that data that should be private is not being inadvertently exposed using weaknesses such as insecure permissions (CWE-732). [REF-7]

Architecture and Design
Libraries or Frameworks

When there is a need to store or transmit sensitive data, use strong, up-to-date cryptographic algorithms to encrypt that data. Select a well-vetted algorithm that is currently considered to be strong by experts in the field, and use well-tested implementations. As with all cryptographic mechanisms, the source code should be available for analysis.
For example, US government systems require FIPS 140-2 certification.
Do not develop custom or private cryptographic algorithms. They will likely be exposed to attacks that are well-understood by cryptographers. Reverse engineering techniques are mature. If the algorithm can be compromised if attackers find out how it works, then it is especially weak.
Periodically ensure that the cryptography has not become obsolete. Some older algorithms, once thought to require a billion years of computing time, can now be broken in days or hours. This includes MD4, MD5, SHA1, DES, and other algorithms that were once regarded as strong. [REF-267]

Architecture and Design
Separation of Privilege

Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.
Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.

Implementation
Architecture and Design
When using industry-approved techniques, use them correctly. Don't cut corners by skipping resource-intensive steps (CWE-325). These steps are often essential for preventing common attacks.

Implementation
Attack Surface Reduction
Use naming conventions and strong types to make it easier to spot when sensitive data is being used. When creating structures, objects, or other complex entities, separate the sensitive and non-sensitive data as much as possible.
Defense in Depth
This makes it easier to spot places in the code where data is being used that is unencrypted.

This code writes a user's login information to a cookie so the user does not have to login again later.

function persistLogin($username, $password){$data = array("username" => $username, "password"=> $password);setcookie ("userdata", $data);}

The code stores the user's username and password in plaintext in a cookie on the user's machine. This exposes the user's login information if their computer is compromised by an attacker. Even if the user's machine is not compromised, this weakness combined with cross-site scripting (CWE-79) could allow an attacker to remotely copy the cookie.
Also note this example code also exhibits Plaintext Storage in a Cookie (CWE-315).

The following code attempts to establish a connection, read in a password, then store it to a buffer.

server.sin_family = AF_INET; hp = gethostbyname(argv[1]);if (hp==NULL) error("Unknown host");memcpy( (char *)&server.sin_addr,(char *)hp->h_addr,hp->h_length);if (argc < 3) port = 80;else port = (unsigned short)atoi(argv[3]);server.sin_port = htons(port);if (connect(sock, (struct sockaddr *)&server, sizeof server) < 0) error("Connecting");...while ((n=read(sock,buffer,BUFSIZE-1))!=-1) {

write(dfd,password_buffer,n);...

While successful, the program does not encrypt the data before writing it to a buffer, possibly exposing it to unauthorized actors.

The following code attempts to establish a connection to a site to communicate sensitive information.

try {URL u = new URL("http://www.secret.example.org/");HttpURLConnection hu = (HttpURLConnection) u.openConnection();hu.setRequestMethod("PUT");hu.connect();OutputStream os = hu.getOutputStream();hu.disconnect();}catch (IOException e) {

//...

}

Though a connection is successfully made, the connection is unencrypted and it is possible that all sensitive data sent to or received from the server will be read by unintended actors.

CVE-2022-26390
wireless battery product stores credentials and Personal Health Information (PHI) without encryption
https://www.cve.org/CVERecord?id=CVE-2022-26390

CVE-2009-2272
password and username stored in cleartext in a cookie
https://www.cve.org/CVERecord?id=CVE-2009-2272

CVE-2009-1466
password stored in cleartext in a file with insecure permissions
https://www.cve.org/CVERecord?id=CVE-2009-1466

CVE-2009-0152
chat program disables SSL in some circumstances even when the user says to use SSL.
https://www.cve.org/CVERecord?id=CVE-2009-0152

CVE-2009-1603
Chain: product uses an incorrect public exponent when generating an RSA key, which effectively disables the encryption
https://www.cve.org/CVERecord?id=CVE-2009-1603

CVE-2009-0964
storage of unencrypted passwords in a database
https://www.cve.org/CVERecord?id=CVE-2009-0964

CVE-2008-6157
storage of unencrypted passwords in a database
https://www.cve.org/CVERecord?id=CVE-2008-6157

CVE-2008-6828
product stores a password in cleartext in memory
https://www.cve.org/CVERecord?id=CVE-2008-6828

CVE-2008-1567
storage of a secret key in cleartext in a temporary file
https://www.cve.org/CVERecord?id=CVE-2008-1567

CVE-2008-0174
SCADA product uses HTTP Basic Authentication, which is not encrypted
https://www.cve.org/CVERecord?id=CVE-2008-0174

CVE-2007-5778
login credentials stored unencrypted in a registry key
https://www.cve.org/CVERecord?id=CVE-2007-5778

CVE-2002-1949
Passwords transmitted in cleartext.
https://www.cve.org/CVERecord?id=CVE-2002-1949

CVE-2008-4122
Chain: Use of HTTPS cookie without "secure" flag causes it to be transmitted across unencrypted HTTP.
https://www.cve.org/CVERecord?id=CVE-2008-4122

CVE-2008-3289
Product sends password hash in cleartext in violation of intended policy.
https://www.cve.org/CVERecord?id=CVE-2008-3289

CVE-2008-4390
Remote management feature sends sensitive information including passwords in cleartext.
https://www.cve.org/CVERecord?id=CVE-2008-4390

CVE-2007-5626
Backup routine sends password in cleartext in email.
https://www.cve.org/CVERecord?id=CVE-2007-5626

CVE-2004-1852
Product transmits Blowfish encryption key in cleartext.
https://www.cve.org/CVERecord?id=CVE-2004-1852

CVE-2008-0374
Printer sends configuration information, including administrative password, in cleartext.
https://www.cve.org/CVERecord?id=CVE-2008-0374

CVE-2007-4961
Chain: cleartext transmission of the MD5 hash of password enables attacks against a server that is susceptible to replay (CWE-294).
https://www.cve.org/CVERecord?id=CVE-2007-4961

CVE-2007-4786
Product sends passwords in cleartext to a log server.
https://www.cve.org/CVERecord?id=CVE-2007-4786

CVE-2005-3140
Product sends file with cleartext passwords in e-mail message intended for diagnostic purposes.
https://www.cve.org/CVERecord?id=CVE-2005-3140

Failure to encrypt data

A8
Insecure Cryptographic Storage
CWE More Specific

A9
Insecure Communications
CWE More Specific

A8
Insecure Storage
CWE More Specific

4
Insufficient Transport Layer Protection

MSC00-J
Use SSLSocket rather than Socket for secure data exchange

SFP23
Exposed Data

Part 3-3
Req SR 4.1

Part 3-3
Req SR 4.3

Part 4-2
Req CR 4.1

Part 4-2
Req CR 7.3

Part 4-2
Req CR 1.5

Discouraged
CWE-311 is high-level with more precise children available. It is a level-1 Class (i.e., a child of a Pillar).
Consider children CWE-312: Cleartext Storage of Sensitive Information or CWE-319: Cleartext Transmission of Sensitive Information.

There is an overlapping relationship between insecure storage of sensitive information (CWE-922) and missing encryption of sensitive information (CWE-311). Encryption is often used to prevent an attacker from reading the sensitive data. However, encryption does not prevent the attacker from erasing or overwriting the data.

CLASP
2006-07-19
Draft 3
2006-07-19

Eric Dalci
Cigital
2008-07-01
updated Time_of_Introduction

Veracode
2008-08-15
Suggested OWASP Top Ten 2004 mapping

CWE Content Team
MITRE
2008-09-08
updated Common_Consequences, Relationships, Other_Notes, Taxonomy_Mappings

CWE Content Team
MITRE
2009-10-29
updated Common_Consequences, Other_Notes

CWE Content Team
MITRE
2010-02-16
updated Applicable_Platforms, Common_Consequences, Demonstrative_Examples, Description, Detection_Factors, Likelihood_of_Exploit, Name, Observed_Examples, Potential_Mitigations, References, Related_Attack_Patterns, Relationships, Taxonomy_Mappings, Time_of_Introduction

CWE Content Team
MITRE
2010-04-05
updated Related_Attack_Patterns

CWE Content Team
MITRE
2010-06-21
updated Common_Consequences, Potential_Mitigations, References

CWE Content Team
MITRE
2010-09-27
updated Potential_Mitigations

CWE Content Team
MITRE
2010-12-13
updated Demonstrative_Examples, Observed_Examples, Related_Attack_Patterns

CWE Content Team
MITRE
2011-03-29
updated Demonstrative_Examples

CWE Content Team
MITRE
2011-06-01
updated Relationships, Taxonomy_Mappings

CWE Content Team
MITRE
2011-06-27
updated Relationships

CWE Content Team
MITRE
2011-09-13
updated Potential_Mitigations, Relationships

CWE Content Team
MITRE
2012-05-11
updated Demonstrative_Examples, References, Relationships, Taxonomy_Mappings

CWE Content Team
MITRE
2012-10-30
updated Potential_Mitigations, References

CWE Content Team
MITRE
2013-07-17
updated Relationship_Notes

CWE Content Team
MITRE
2014-02-18
updated Related_Attack_Patterns

CWE Content Team
MITRE
2014-06-23
updated Relationships

CWE Content Team
MITRE
2014-07-30
updated Detection_Factors, Relationships, Taxonomy_Mappings

CWE Content Team
MITRE
2015-12-07
updated Related_Attack_Patterns

CWE Content Team
MITRE
2017-01-19
updated Related_Attack_Patterns

CWE Content Team
MITRE
2017-05-03
updated Related_Attack_Patterns

CWE Content Team
MITRE
2017-11-08
updated Likelihood_of_Exploit, Modes_of_Introduction, Potential_Mitigations, References, Relationships

CWE Content Team
MITRE
2018-03-27
updated References, Relationships

CWE Content Team
MITRE
2019-01-03
updated Related_Attack_Patterns, Relationships, Taxonomy_Mappings

CWE Content Team
MITRE
2019-06-20
updated Related_Attack_Patterns, Relationships, Type

CWE Content Team
MITRE
2020-02-24
updated References, Relationships

CWE Content Team
MITRE
2020-12-10
updated Potential_Mitigations, Relationships

CWE Content Team
MITRE
2021-10-28
updated Relationships

CWE Content Team
MITRE
2022-06-28
updated Relationships

CWE Content Team
MITRE
2023-01-31
updated Description, Potential_Mitigations

CWE Content Team
MITRE
2023-04-27
updated References, Relationships

CWE Content Team
MITRE
2023-06-29
updated Mapping_Notes, Relationships

CWE Content Team
MITRE
2024-02-29
4.14
2024-02-29
updated Taxonomy_Mappings

CWE Content Team
MITRE
2025-04-03
4.17
2025-04-03
updated Description, Diagram

CWE Content Team
MITRE
2025-09-09
4.18
2025-09-09
updated Detection_Factors, References

CWE Content Team
MITRE
2025-12-11
4.19
2025-12-11
updated Observed_Examples, Relationships, Weakness_Ordinalities

participants in the CWE ICS/OT SIG 62443 Mapping Fall Workshop
2023-11-14
4.14
2024-02-29
Contributed or reviewed taxonomy mappings for ISA/IEC 62443

Failure to Encrypt Data
Failure to Encrypt Sensitive Data