CVE-2020-13935 : What You Need to Know

Apache Tomcat versions 7.0.27 to 10.0.0-M6 are affected by a WebSocket frame payload length validation vulnerability that could lead to denial of service.

Understanding CVE-2020-13935

Apache Tomcat is susceptible to a denial of service due to improper validation of payload lengths in WebSocket frames.

What is CVE-2020-13935?

The vulnerability in Apache Tomcat versions 7.0.27 to 10.0.0-M6 arises from inadequate validation of payload lengths in WebSocket frames. Attackers can exploit this flaw to trigger an infinite loop by sending requests with invalid payload lengths, potentially causing a denial of service.

The Impact of CVE-2020-13935

The vulnerability allows malicious actors to exploit WebSocket frames with incorrect payload lengths, leading to a denial of service condition. Multiple requests with malformed payload lengths can exacerbate the impact, potentially causing service disruption.

Technical Details of CVE-2020-13935

Apache Tomcat's vulnerability stems from WebSocket frame payload length validation issues.

Vulnerability Description

The flaw in Apache Tomcat versions 7.0.27 to 10.0.0-M6 allows attackers to exploit WebSocket frames with incorrect payload lengths, potentially triggering an infinite loop and causing denial of service.

Affected Systems and Versions

Apache Tomcat 10.0.0-M1 to 10.0.0-M6
Apache Tomcat 9.0.0.M1 to 9.0.36
Apache Tomcat 8.5.0 to 8.5.56
Apache Tomcat 7.0.27 to 7.0.104

Exploitation Mechanism

Attackers can send multiple requests with invalid payload lengths in WebSocket frames to exploit the vulnerability, potentially leading to a denial of service.

Mitigation and Prevention

Immediate action and long-term security practices are crucial to mitigate the CVE-2020-13935 vulnerability.

Immediate Steps to Take

Apply patches provided by Apache Tomcat to address the vulnerability.
Monitor network traffic for any signs of exploitation.
Implement network-level protections to filter out potentially malicious requests.

Long-Term Security Practices

Regularly update Apache Tomcat to the latest version to prevent known vulnerabilities.
Conduct security assessments and penetration testing to identify and address potential weaknesses.

Patching and Updates

Stay informed about security advisories from Apache Tomcat and promptly apply patches to secure the system.