CVE-2020-13934 : Exploit Details and Defense Strategies

An h2c direct connection to Apache Tomcat 10.0.0-M1 to 10.0.0-M6, 9.0.0.M5 to 9.0.36, and 8.5.1 to 8.5.56 could lead to a denial of service due to an OutOfMemoryException.

Understanding CVE-2020-13934

This CVE involves a vulnerability in Apache Tomcat that could result in a denial of service if exploited.

What is CVE-2020-13934?

This CVE describes a scenario where an h2c direct connection to specific versions of Apache Tomcat does not release the HTTP/1.1 processor after upgrading to HTTP/2. This oversight could potentially trigger an OutOfMemoryException, causing a denial of service if a significant number of such requests are made.

The Impact of CVE-2020-13934

The impact of this vulnerability is the potential for a denial of service due to memory exhaustion, which could disrupt the normal operation of the affected Apache Tomcat instances.

Technical Details of CVE-2020-13934

This section delves into the technical aspects of the CVE.

Vulnerability Description

The vulnerability arises from the failure to release the HTTP/1.1 processor after transitioning to HTTP/2, leading to a possible OutOfMemoryException and subsequent denial of service.

Affected Systems and Versions

Apache Tomcat 10.0.0-M1 to 10.0.0-M6
Apache Tomcat 9.0.0.M5 to 9.0.36
Apache Tomcat 8.5.1 to 8.5.56

Exploitation Mechanism

Exploiting this vulnerability involves establishing an h2c direct connection to the specified versions of Apache Tomcat, not releasing the HTTP/1.1 processor after upgrading to HTTP/2, and generating a sufficient number of requests to trigger an OutOfMemoryException.

Mitigation and Prevention

Protecting systems from CVE-2020-13934 requires specific actions to mitigate the risk.

Immediate Steps to Take

Apply the necessary security patches provided by Apache Tomcat promptly.
Monitor system resources for any signs of unusual memory consumption.
Implement network-level protections to mitigate denial-of-service attacks.

Long-Term Security Practices

Regularly update and patch Apache Tomcat installations to address known vulnerabilities.
Conduct security assessments and audits to identify and remediate potential weaknesses.

Patching and Updates

Stay informed about security advisories and updates from Apache Tomcat.
Follow best practices for secure configuration and deployment of Apache Tomcat instances.