CVE-2021-44224 : Exploit Details and Defense Strategies

Understanding CVE-2021-44224

CVE-2021-44224 is a vulnerability in Apache HTTP Server versions 2.4.7 to 2.4.51 that can lead to NULL pointer dereference or Server Side Request Forgery (SSRF) when handling crafted URIs.

What is CVE-2021-44224?

The vulnerability allows attackers to crash the server or redirect requests to a Unix Domain Socket endpoint when Apache HTTP Server is configured as a forward proxy with ProxyRequests on.

The Impact of CVE-2021-44224

This vulnerability affects a wide range of Apache HTTP Server versions and can be exploited to cause denial of service or manipulate server requests, posing a moderate threat.

Technical Details of CVE-2021-44224

The vulnerability involves a specific configuration of Apache HTTP Server and has the following details:

Vulnerability Description

A crafted URI can trigger a NULL pointer dereference or result in SSRF, affecting versions 2.4.7 to 2.4.51.

Affected Systems and Versions

Product: Apache HTTP Server
Vendor: Apache Software Foundation
Versions affected: 2.4.7 up to 2.4.51

Exploitation Mechanism

Attackers can exploit misconfigured Apache HTTP Server setups with ProxyRequests enabled to perform SSRF attacks or cause server crashes.

Mitigation and Prevention

It is crucial to take immediate steps to address the CVE-2021-44224 vulnerability and implement long-term security practices:

Immediate Steps to Take

Update Apache HTTP Server to a patched version immediately.
Disable ProxyRequests if not essential for server functionality.
Monitor and restrict external URI access.

Long-Term Security Practices

Regularly update and patch software to prevent known vulnerabilities.
Conduct security audits and penetration testing on server configurations.
Educate IT teams on secure server configuration best practices.
Implement network security measures to monitor and block malicious traffic.

Patching and Updates

Apply patches provided by Apache Software Foundation to address CVE-2021-44224 and regularly check for updates to mitigate emerging threats.