** UNSUPPORTED WHEN ASSIGNED ** Improper Output Neutralization for Logs vulnerability in Apache Struts.
This issue affects Apache Struts Extras: before 2.
When using LookupDispatchAction, in some cases, Struts may print untrusted input to the logs without any filtering. Specially-crafted input may lead to log output where part of the message masquerades as a separate log line, confusing consumers of the logs (either human or automated).
As this project is retired, we do not plan to release a version that fixes this issue. Users are recommended to find an alternative or restrict access to the instance to trusted users.
NOTE: This vulnerability only affects products that are no longer supported by the maintainer.
Weakness
The product does not neutralize or incorrectly neutralizes output that is written to logs.
Affected Software
| Name |
Vendor |
Start Version |
End Version |
| Struts_extras |
Apache |
* |
2.0 (excluding) |
Extended Description
This can allow an attacker to forge log entries or inject malicious content into logs.
Log forging vulnerabilities occur when:
Potential Mitigations
- Assume all input is malicious. Use an “accept known good” input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
- When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, “boat” may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as “red” or “blue.”
- Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code’s environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
References