CVE-2021-25329 : Exploit Details and Defense Strategies
Learn about CVE-2021-25329, an incomplete fix for CVE-2020-9484 in Apache Tomcat versions 7.0.0 to 10.0.0, allowing remote code execution. Find mitigation steps and long-term security practices.
Apache Tomcat versions 7.0.0 to 10.0.0 were affected by an incomplete fix for CVE-2020-9484. This issue, identified by Trung Pham of Viettel Cyber Security, allowed remote code execution via session persistence. Even though the scenario for exploitation was highly unlikely, certain edge cases still left Tomcat instances vulnerable to CVE-2020-9494. It's important to note that the prerequisites and mitigations for CVE-2020-9484 also apply here.
Understanding CVE-2021-25329
What is CVE-2021-25329?
CVE-2021-25329 refers to an incomplete fix for CVE-2020-9484 in Apache Tomcat versions 7.0.0 to 10.0.0, leading to potential remote code execution through session persistence.
The Impact of CVE-2021-25329
The vulnerability could allow an attacker to exploit a specific configuration edge case, although the likelihood of exploitation was low. However, it posed a risk of remote code execution in affected Apache Tomcat instances.
Technical Details of CVE-2021-25329
Vulnerability Description
The issue stemmed from an incomplete fix for CVE-2020-9484, leaving Tomcat versions 7.0.0 to 10.0.0 susceptible to remote code execution via session persistence in rare edge cases.
Affected Systems and Versions
- Apache Tomcat 10.0.0-M1 to 10.0.0
- Apache Tomcat 9.0.0.M1 to 9.0.41
- Apache Tomcat 8.5.0 to 8.5.61
- Apache Tomcat 7.0.0 to 7.0.107
Exploitation Mechanism
Exploitation of this vulnerability involved leveraging the incomplete fix for CVE-2020-9484 in Apache Tomcat instances, potentially leading to remote code execution through session persistence.
Mitigation and Prevention
Immediate Steps to Take
It is recommended to update affected Apache Tomcat versions to the latest secure releases, ensuring that the incomplete fix for CVE-2020-9484 is addressed properly.
Long-Term Security Practices
To enhance security posture, organizations should regularly monitor Apache Tomcat security advisories, apply patches promptly, and adhere to secure configuration best practices.
Patching and Updates
Stay informed about security updates and advisories from Apache Tomcat's official sources to mitigate the risk of potential vulnerabilities like CVE-2021-25329.