CWE-134 — Use of Externally-Controlled Format String
CWE-134: Use of Externally-Controlled Format String
MITRE CWE weakness
| Kind | Weakness |
| Abstraction | Base |
| Status | Draft |
| Likelihood of exploit | High |
Description
The product uses a function that accepts a format string as an argument, but the format string originates from an external source.
Common consequences
- Confidentiality: Read Memory
- Integrity, Confidentiality, Availability: Modify Memory, Execute Unauthorized Code or Commands
Mitigations
Requirements — Choose a language that is not subject to this flaw.
Implementation — Ensure that all format string functions are passed a static string which cannot be controlled by the user, and that the proper number of arguments are always sent to that function as well. If at all possible, use functions that do not support the %n operator in format strings. [REF-116] [REF-117]
Build and Compilation — Run compilers and linkers with high warning levels, since they may detect incorrect usage.
References
- CWE page: https://cwe.mitre.org/data/definitions/134.html
- CWE list: https://cwe.mitre.org/data/index.html