|
|
|
|
CWE-123 Individual Dictionary Definition (Draft 9)
Weakness ID
| Status: Draft 123 (Weakness Base) | | Description | Summary Any condition where the attacker has the ability to write an arbitrary value to an
arbitrary location, often as the result of a buffer overflow. | | Likelihood of Exploit | High | | Weakness Ordinality | Resultant (Weakness is typically related to the presence of some other weaknesses) | | Causal Nature | Explicit (This is an explicit weakness resulting from behavior of the developer) | | Common Consequences | Access control (memory and instruction processing): Clearly, write-what-where
conditions can be used to write data to areas of memory outside the scope of a policy. Also,
they almost invariably can be used to execute arbitrary code, which is usually outside the
scope of a program's implicit security policy. Availability: Many memory accesses can lead to program termination, such as
when writing to addresses that are invalid for the current process. Other: When the consequence is arbitrary code execution, this can often be
used to subvert any other security service. | | Potential Mitigations | Pre-design: Use a language that provides appropriate memory abstractions. Design: Integrate technologies that try to prevent the consequences of this problem. Implementation: Take note of mitigations provided for other flaws in this taxonomy
that lead to write-what-where conditions. Operational: Use OS-level preventative functionality integrated after the fact. Not a
complete solution. | | Context Notes | When the attacker has the ability to write arbitrary data to an arbitrary location in
memory, the consequences are often arbitrary code execution. If the attacker can overwrite a
pointer's worth of memory (usually 32 or 64 bits), he can redirect a function pointer to his own
malicious code. Even when the attacker can only modify a single byte using a write-what-where
problem, arbitrary code execution can be possible. Sometimes this is because the same problem can
be exploited repeatedly to the same effect. Other times it is because the attacker can overwrite
security-critical application-specific data -- such as a flag indicating whether the user is an
administrator. | | Relationships | | | Source Taxonomies | CLASP - Write-what-where condition | | Applicable Platforms | C C++ |
|