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CWE
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Untrusted Pointer Dereference

ID: 822Date: (C)2012-05-14   (M)2012-11-08
Type: weaknessStatus: INCOMPLETE
Abstraction Type: Base





Description

The program obtains a value from an untrusted source, converts this value to a pointer, and dereferences the resulting pointer.

Extended Description

An attacker can supply a pointer for memory locations that the program is not expecting. If the pointer is dereferenced for a write operation, the attack might allow modification of critical program state variables, cause a crash, or execute code. If the dereferencing operation is for a read, then the attack might allow reading of sensitive data, cause a crash, or set a program variable to an unexpected value (since the value will be read from an unexpected memory location).

There are several variants of this weakness, including but not necessarily limited to:

The untrusted value is directly invoked as a function call.

In OS kernels or drivers where there is a boundary between "userland" and privileged memory spaces, an untrusted pointer might enter through an API or system call (see CWE-781 for one such example).

Inadvertently accepting the value from an untrusted control sphere when it did not have to be accepted as input at all. This might occur when the code was originally developed to be run by a single user in a non-networked environment, and the code is then ported to or otherwise exposed to a networked environment.

Applicable Platforms
None

Related Attack Patterns

Common Consequences

ScopeTechnical ImpactNotes
Confidentiality
 
Read memory
 
If the untrusted pointer is used in a read operation, an attacker might be able to read sensitive portions of memory.
 
Availability
 
DoS: crash / exit / restart
 
If the untrusted pointer references a memory location that is not accessible to the program, or points to a location that is "malformed" or larger than expected by a read or write operation, the application may terminate unexpectedly.
 
Integrity
Confidentiality
Availability
 
Execute unauthorized code or commands
Modify memory
 
If the untrusted pointer is used in a function call, or points to unexpected data in a write operation, then code execution may be possible.
 

Detection Methods
None

Potential Mitigations
None

Relationships

Related CWETypeViewChain
CWE-822 ChildOf CWE-876 Category CWE-868  

Demonstrative Examples
None

Observed Examples

  1. CVE-2007-5655 : message-passing framework interprets values in packets as pointers, causing a crash.
  2. CVE-2010-2299 : labeled as a "type confusion" issue, also referred to as a "stale pointer." However, the bug ID says "contents are simply interpreted as a pointer... renderer ordinarily doesn't supply this pointer directly". The "handle" in the untrusted area is replaced in one function, but not another - thus also, effectively, exposure to wrong sphere (CWE-668).
  3. CVE-2009-1719 : Untrusted dereference using undocumented constructor.
  4. CVE-2009-1250 : An error code is incorrectly checked and interpreted as a pointer, leading to a crash.
  5. CVE-2009-0311 : An untrusted value is obtained from a packet and directly called as a function pointer, leading to code execution.
  6. CVE-2010-1818 : Undocumented attribute in multimedia software allows "unmarshaling" of an untrusted pointer.
  7. CVE-2010-3189 : ActiveX control for security software accepts a parameter that is assumed to be an initialized pointer.
  8. CVE-2010-1253 : Spreadsheet software treats certain record values that lead to "user-controlled pointer" (might be untrusted offset, not untrusted pointer).

For more examples, refer to CVE relations in the bottom box.

White Box Definitions
None

Black Box Definitions
None

Taxynomy Mappings

TaxynomyIdNameFit
CERT C++ Secure Coding MEM10-CPP
 
Define and use a pointer validation function
 
 

References:
None

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