CVE-2021-33193 : Security Advisory and Response

A crafted method sent through HTTP/2 can bypass validation and be forwarded by mod_proxy, leading to request splitting or cache poisoning. This vulnerability affects Apache HTTP Server versions 2.4.17 to 2.4.48.

Understanding CVE-2021-33193

This section dives into the details of the CVE-2021-33193 vulnerability affecting Apache HTTP Server.

What is CVE-2021-33193?

The CVE-2021-33193 vulnerability involves request splitting via HTTP/2 method injection and mod_proxy in Apache HTTP Server, potentially resulting in cache poisoning.

The Impact of CVE-2021-33193

The impact of this vulnerability includes the potential for request splitting or cache poisoning, which can lead to security breaches and unauthorized access.

Technical Details of CVE-2021-33193

This section provides detailed technical insights into the CVE-2021-33193 vulnerability.

Vulnerability Description

The vulnerability allows a specially crafted method sent via HTTP/2 to bypass validation and be forwarded by mod_proxy, creating the risk of request splitting and cache poisoning.

Affected Systems and Versions

Apache HTTP Server versions 2.4.17 to 2.4.48 are affected by this vulnerability, emphasizing the need for immediate action to mitigate potential risks.

Exploitation Mechanism

The vulnerability is exploited by sending a malicious method through HTTP/2, which evades validation and is forwarded by mod_proxy, enabling request splitting and cache poisoning.

Mitigation and Prevention

Understanding how to mitigate and prevent CVE-2021-33193 is crucial to maintain system security.

Immediate Steps to Take

Organizations using affected versions of Apache HTTP Server must apply security patches promptly and monitor for any suspicious activities that could indicate exploitation of this vulnerability.

Long-Term Security Practices

Implementing robust security measures, conducting regular security audits, and ensuring up-to-date software updates are essential for long-term protection against potential security risks.

Patching and Updates

Apache Software Foundation provides patches to address this vulnerability. Stay informed about security updates and apply patches promptly to prevent exploitation.