CVE-2020-11996 Explained : Impact and Mitigation

Apache Tomcat versions 10.0.0-M1 to 10.0.0-M5, 9.0.0.M1 to 9.0.35, and 8.5.0 to 8.5.55 are affected by a vulnerability that could lead to a denial of service due to high CPU usage.

Understanding CVE-2020-11996

A denial of service vulnerability affecting Apache Tomcat versions 10.0.0-M1 to 10.0.0-M5, 9.0.0.M1 to 9.0.35, and 8.5.0 to 8.5.55.

What is CVE-2020-11996?

A specially crafted sequence of HTTP/2 requests can trigger high CPU usage, potentially causing the server to become unresponsive.

The Impact of CVE-2020-11996

Exploitation of this vulnerability could lead to a denial of service by causing high CPU usage.
If a sufficient number of malicious requests are made concurrently, the server may become unresponsive.

Technical Details of CVE-2020-11996

This section provides more technical insights into the vulnerability.

Vulnerability Description

Sending a specific sequence of HTTP/2 requests to affected Apache Tomcat versions can result in high CPU usage.

Affected Systems and Versions

Apache Tomcat versions 10.0.0-M1 to 10.0.0-M5
Apache Tomcat versions 9.0.0.M1 to 9.0.35
Apache Tomcat versions 8.5.0 to 8.5.55

Exploitation Mechanism

Attackers can exploit this vulnerability by sending crafted HTTP/2 requests to the affected Apache Tomcat servers.

Mitigation and Prevention

Protect your systems from CVE-2020-11996 with these mitigation strategies.

Immediate Steps to Take

Apply the necessary security patches provided by Apache to address this vulnerability.
Monitor server performance for any signs of unusual CPU usage that could indicate an ongoing attack.

Long-Term Security Practices

Regularly update and patch your Apache Tomcat installations to prevent known vulnerabilities.
Implement network-level protections to filter out potentially malicious HTTP/2 requests.

Patching and Updates

Stay informed about security updates and advisories from Apache to promptly address any new vulnerabilities.