CVE-2025-54656: Apache Struts Extras Log Injection Vulnerability
This post details a security vulnerability, CVE-2025-54656, affecting Apache Struts Extras. While the project is now retired, understanding this issue can help you secure legacy systems or prevent similar flaws in other applications.
TL;DR Summary
CVE-2025-54656 is a log injection vulnerability in Apache Struts Extras, specifically when using LookupDispatchAction. Malicious input can be injected into logs, potentially misleading log analysis. Since Struts Extras is no longer supported, a patch is unavailable. Mitigation involves either migrating to a supported framework or restricting access to trusted users only.
Vulnerability Details
- CVE ID: CVE-2025-54656
- Description: Improper Output Neutralization for Logs vulnerability in Apache Struts Extras. When using
LookupDispatchAction, untrusted input may be printed to logs without sanitization. This can lead to injected log lines, confusing log analysis tools or personnel. - CVSS Score: 6.5 (Medium)
- CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
- CVSS Explanation:
- AV:N (Network): Vulnerability can be exploited over the network.
- AC:L (Low): Attack doesn't require unusual effort from the attacker.
- PR:N (None): No privileges are required to exploit the vulnerability.
- UI:N (None): No user interaction is needed.
- S:U (Unchanged): The vulnerability affects only the vulnerable component.
- C:L (Low): Limited impact on confidentiality.
- I:L (Low): Limited impact on integrity.
- A:N (None): No impact on availability.
- Exploit Requirements: The application must be using the
LookupDispatchActionin Struts Extras and logging user-provided input. - Affected Vendor: Apache
- Affected Product: Struts Extras
- Affected Version: Before 2
- CWE: CWE-117 - Improper Output Neutralization for Logs
Timeline of Events
- 2025-07-30: CVE-2025-54656 Published
Exploitability & Real-World Risk
While the CVSS score is medium, the real-world risk depends on how logs are used. If logs are parsed by automated systems for security monitoring or auditing, a log injection could allow an attacker to hide malicious activity or trigger false alarms. The impact is greater if logging is centralized and used across multiple applications, potentially affecting other systems.
Recommendations
- Migration: The primary recommendation is to migrate away from Apache Struts Extras to a supported framework.
- Restrict Access: If migration is not feasible, restrict access to the Struts Extras instance to trusted users only.
- Log Sanitization (If Possible): If you must continue using Struts Extras and cannot restrict access, attempt to implement custom log sanitization. However, this is not recommended as a long-term solution, as it might not be comprehensive.
Technical Insight
The vulnerability stems from the fact that user-provided input is directly written to logs without any form of escaping or sanitization. An attacker can craft input containing special characters (like newline characters) that will be interpreted by log viewers as new log entries. This allows the attacker to inject arbitrary content into the logs.
Credit to Researcher(s)
The original advisory doesn't explicitly credit a researcher. This section will be updated if more information becomes available.
References
Tags
#CVE-2025-54656 #ApacheStruts #LogInjection #CWE-117 #SecurityVulnerability #Unsupported
Summary: CVE-2025-54656 is a log injection vulnerability in Apache Struts Extras, affecting versions before 2. When using LookupDispatchAction, untrusted input may be printed to the logs without any filtering. This can lead to log output where part of the message masquerades as a separate log line, confusing log consumers. The project is retired, so migration to a supported framework or restriction of access to trusted users is recommended.
CVE ID: CVE-2025-54656
Risk Analysis: Successful exploitation could allow an attacker to inject false or misleading information into logs, potentially hiding malicious activity, triggering false alarms, or confusing incident response efforts. This is particularly risky if logs are used for auditing or security monitoring.
Recommendation: Migrate to a supported web framework or restrict access to the Struts Extras instance to trusted users. Implement log sanitization if possible, but this is not recommended as a complete solution.
Timeline
- 2025-07-30: CVE-2025-54656 was published.