Abstract:
A method for detecting an attempted attack on a security system. In one preferred embodiment of the present invention, the method includes the step of retrieving a parameter from a hardware system, wherein the parameter changes during an operation of the hardware system. Then, comparing the retrieved parameter with a previously stored parameter; and, detecting a lack of change between the retrieved parameter and the previously stored parameter. An apparatus and an article of manufacture for detecting an attempted attack on a security system is also disclosed.

Description:
CLAIM OF PRIORITY UNDER 35 U.S.C. §119  
       [0001]     The present Application for Patent claims priority to Provisional Application No. 60/713,926, entitled “Method for detection of tampering attacks attempts against systems that use computing environments for identification purposes” filed Sep. 2, 2005, and assigned to the assignee hereof and hereby expressly incorporated by reference herein. 
     
    
     BACKGROUND  
       [0002]     1. Field  
         [0003]     The present invention relates generally to security in computing environments, and more particularly, to a method and apparatus for detection of tampering attacks against systems that use computing environments for identification purposes.  
         [0004]     2. Background  
         [0005]     Using a non-user configurable environment of a computing system has become a popular way of authenticating devices that run security programs as well as for managing the valid use of copy controlled and licensed software.  
         [0006]     The use of parameter information to build a unique identity for that computing system is typically deployed in the software publishing and digital rights management industry. One common term used to describe the process is called hardware fingerprinting.  
         [0007]     One of the important improvements to hardware fingerprinting is the concept of tolerance, which allows the computing system to tolerate a small number of changes to its environment without triggering a failure. A failure of the process occurs when the protected software detects that it is in use on a new or unknown device and therefore requires re-authentication.  
         [0008]     The practice known as tolerance involves making queries to multiple device parameters and making a weighted and or prioritized decision about how many of those parameters are allowed to change before the controlling software decides to treat the computing environment as a new and unknown system requiring manual re-authentication.  
         [0009]     The hardware fingerprinting system may be circumvented, however, if a rogue entity is able to interfere with the detection process of the protected software. For example, the rogue entity may emulate the hardware fingerprint of the original computing environment to fool the protected software to think that it is executing in the original computing environment.  
       SUMMARY OF THE PREFERRED EMBODIMENTS  
       [0010]     The present invention provides a method for detecting an attempted attack on a security system. In one preferred embodiment of the present invention, the method includes the step of retrieving a parameter from a hardware system, wherein the parameter changes during an operation of the hardware system. Then, comparing the retrieved parameter with a previously stored parameter; and, detecting a lack of change between the retrieved parameter and the previously stored parameter.  
         [0011]     An apparatus for detecting a tampering attempt in a security system is also disclosed. The apparatus includes a processor and a memory coupled to the processor. In one preferred embodiment, the memory is configured to cause the processor to execute a method including the step of retrieving a parameter from a hardware system, wherein the parameter changes during an operation of the hardware system. Then, comparing the retrieved parameter with a previously stored parameter; and, detecting a lack of change between the retrieved parameter and the previously stored parameter.  
         [0012]     An article of manufacture including a computer-readable medium having instructions stored thereon for causing a processor to perform a method for detecting an attempted attack on a security system is also disclosed. The method including the steps of retrieving a parameter from a hardware system, wherein the parameter changes during an operation of the hardware system. Then, comparing the retrieved parameter with a previously stored parameter; and, detecting a lack of change between the retrieved parameter and the previously stored parameter.  
         [0013]     Other objects, features and advantages will become apparent to those skilled in the art from the following detailed description. It is to be understood, however, that the detailed description and specific examples, while indicating exemplary embodiments, are given by way of illustration and not limitation. Many changes and modifications within the scope of the following description may be made without departing from the spirit thereof, and the description should be understood to include all such variations.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]     The invention may be more readily understood by referring to the accompanying drawings in which:  
         [0015]      FIG. 1  illustrates an example of sample sets used in an identification process.  
         [0016]      FIG. 2  illustrates an example of existing software to device communications.  
         [0017]      FIG. 3  illustrates an example of an existing method for tampering with software to device communications.  
         [0018]      FIG. 4  illustrates an identification and tamper detection process that can be used to uniquely identify a computer system or a change thereto, and detect an attempt to tamper with software to device communications. 
     
    
       [0019]     Like numerals refer to like parts throughout the several views of the drawings.  
       DETAILED DESCRIPTION  
       [0020]     The present invention goes beyond standard tolerance systems to use the tolerance process and device parameters queries as a means of detecting when the software is under attack thereby allowing the software to take countermeasures to defend itself.  
         [0021]     The invention is valuable in that it can be used to protect software that is used for security or copy control applications.  
         [0022]     Further, the invention has significant value when compared with traditional anti-piracy and anti-tampering techniques such as check summing and encryption in that these can be configured to more effectively protect the target software when an attack has been detected.  
         [0023]     The present invention will provide a method of detecting when attempts have been made to circumvent or interfere with security or copy control systems that use the non-user configurable information from a computing device for the purposes of identification and authentication.  
         [0024]     One of the many ways to sample a computing environment for the purposes of uniquely identifying one system from another is to collect information from many or all available devices and many or all available device parameters to use them as a digital identifier.  
         [0025]      FIG. 1  describes one example of three sets of computing system device parameters ( 10 ,  20  and  30 ) that can be used for both uniquely identifying a computer system ( 10  and  20 ) and one set of device parameters ( 30 ) that can be used for detecting when an attacker is attempting to tamper with data collected during the query of device parameters.  
         [0026]     In  FIG. 1 , the first device parameter set  10  contains devices  11  and device parameters  12  that rarely change from one query to the next in a series of successive queries over time. Examples of device parameters that rarely change over time on a computer are the device parameter for the manufacturer of the motherboard and the make and model parameters for the central processing unit. The devices in this set can also be included in other sets. That is, devices may have one or more parameter in each of the device parameter sets  10 ,  20 , and  30 . However, device parameters cannot be shared across different sets since device parameters are unique to each set of device parameters.  
         [0027]     The second set of device parameters  20  also contains devices  21  and device parameters  22 . However, these device parameters are different from the device parameters  12  of the first set  10  in that these device parameters  22  do change from time to time during the course of the useful life of the computing system. Examples of device parameters that can change over time on a computer are the device parameter related to the amount of random access memory contained in the computer and the device parameter related to the serial number(s) of the hard drive(s) in the computer.  
         [0028]     The third set of device parameters  30  also contains devices  31  and device parameters  32 . Unlike the first device parameters set  10  and the second parameter set  20 , the third device parameter set  30  includes only device parameters that change over time during the operation of the computer. Device parameters that change on a computer include, but are not limited to, device parameters related to the keeping track of time on the computing system and device parameters related to data that rapidly changes while the device is in use by a processing unit or random access memory. For example, the amount of memory used as well as the content of the random access memory may be used as device parameters.  
         [0029]      FIG. 2  illustrates a normal communication  62  between software  60  that is protected from execution on unauthorized systems by verifying the identity of the computer system with the use of queries to device parameters  61 .  
         [0030]      FIG. 3  illustrates a scenario of compromised communications  64  between protected software  60  and device parameters  61  (as described in  FIG. 2 ). Specifically,  FIG. 3  illustrates how tampering software  63  can be used to intercept software communications  62  between the protected software  60  and the computing systems device parameters  61  and return false information in the form of compromised communications  64  in an attempt to allow the protected software  60  to run on unauthorized computer systems, such as a computer system having different device parameters  65 .  
         [0031]     During the process of sampling a computer operating environment to build a unique identifier for that system the software usually collects a wide and diverse range of device parameters  10  and  20 . There are numerous approaches for using these device parameters for the production of a unique identifier. The present invention adds an additional functionality to the sampling process by sampling device parameters that are known to always change  30 .  
         [0032]      FIG. 4  describes a process configured in accordance to one preferred invention of the present invention for use in a computer identification system that includes the ability to uniquely identify a computing system and detect when tampering is being attempted against the identification system.  
         [0033]     Initially, the parameters of the first set of device parameters  10  are queried using a series of software commands in step  402 . The results of this query in step  402  are compared with a stored version of the same parameter query in step  404 . The results of the comparison are then computed in step  406 . If major changes are found between the stored version of the query and the generated version of the query in step  406  then the authentication process fails and operation continues with step  408 . If there are minor or no changes detected in the comparison of the stored parameter query and generated version in step  406 , then the process proceeds to step  420 .  
         [0034]     Queries are made for device parameters that are allowed to change in step  420 . These are compared with a stored version of the same query in step  424 . If too many changes are detected in step  426 , then the authentication fails and operation continues with step  428 . If an allowable number of changes are detected in step  426  then the process proceeds to step  440 .  
         [0035]     Next queries are made for device parameters that must always change in step  440 . These are compared with a stored version of the same query in step  444 . If no changes are detected in  446 , then authentication fails and operation continues with step  448 . However, if changes are detected in step  446 , then the authentication is considered to have been successfully completed and operation continues with  450 .  
         [0036]     As discussed herein, the present invention adds an additional functionality to the sampling process by sampling device parameters that are known to always change  30 . This functionality serves the purpose of laying a trap for attackers or others who wishes to tamper with the software  60  since a standard way of attacking and stress testing software is to intercept the normal communications  62  of the software  60  with the computing environment and the operating system and to feed falsified or compromised information  64  to the software  60 . The intent is to deceive the software  60  into allowing it to run in an unprotected or compromised state.  
         [0037]     Since the attacker is in the process of learning what information is needed by the software  60  to run in a compromised state, the attacker is initially unaware of what information is required by the software  60  to operate successfully.  
         [0038]     The presumption that there is a correct answer to any query made by the software  60  means that the attacker will attempt to send data in different combinations, including duplicate values, to the software the attacker is trying to defeat.  
         [0039]     Herein is the value of the invention in that sending duplicate data to a device parameter query that is intentionally meant to be different on every query means that attempted tampering can be detected, as discussed above in  FIG. 4 , and countermeasures taken.  
         [0040]     An alternative embodiment could include where the querying of the device parameters does not occur in three separate processes, but where each individual device parameter is queried individually in a randomized or varied order so that queries to device parameters that must always change  32  are interspersed with queries to device parameters that sometimes change  22  and others where the device parameters rarely change  12 . This approach increases the difficulty for an attacker to determine which queries are designed as tamper detection steps versus the queries that are part of the normal identification and authentication process.  
         [0041]     Another alternative embodiment could include but is not to be limited to a system as described in  FIG. 4 , where device parameters are not separated into different sets but are queried as one continuous set. The method is still useful in this scenario since the object of using it is to detect tampering and not to add capabilities to the tolerance process as such.  
         [0042]     It should be noted that the methods described herein may be implemented on a variety of communication hardware, processors and systems known by one of ordinary skill in the art. The various illustrative logics, logical blocks, modules, and circuits described in connection with the embodiments disclosed herein may be implemented or performed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but, in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.  
         [0043]     The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor, such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.  
         [0044]     The embodiments described above are exemplary embodiments. Those skilled in the art may now make numerous uses of, and departures from, the above-described embodiments without departing from the inventive concepts disclosed herein. Various modifications to these embodiments may be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments, without departing from the spirit or scope of the novel aspects described herein. Thus, the scope of the invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. The word “exemplary” is used exclusively herein to mean “serving as an example, instance, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as the most preferred or advantageous over other embodiments. Accordingly, the present invention is to be defined solely by the scope of the following claims.