CVE-2021-40346 Explained : Impact and Mitigation

This CVE entry pertains to an integer overflow vulnerability in HAProxy versions 2.0 through 2.5 that can lead to an HTTP request smuggling attack.

Understanding CVE-2021-40346

This section delves into the details of the CVE-2021-40346 vulnerability.

What is CVE-2021-40346?

An integer overflow flaw exists in the 'htx_add_header' function of HAProxy versions 2.0 through 2.5. Exploiting this vulnerability enables an attacker to execute an HTTP request smuggling attack, bypassing configured HAProxy ACLs and potentially other ACLs.

The Impact of CVE-2021-40346

The CVE-2021-40346 vulnerability allows attackers to bypass HTTP request HAProxy ACLs and potentially other ACLs, gaining unauthorized access and compromising system integrity.

Technical Details of CVE-2021-40346

This section covers the technical aspects of CVE-2021-40346.

Vulnerability Description

The vulnerability arises from an integer overflow in the 'htx_add_header' function of HAProxy versions 2.0 through 2.5, facilitating HTTP request smuggling attacks.

Affected Systems and Versions

Affected Version: HAProxy 2.0 to 2.5
Product: HAProxy
Vendor: N/A

Exploitation Mechanism

The vulnerability can be exploited by malicious actors to execute an HTTP request smuggling attack, which enables them to bypass configured http-request HAProxy ACLs and potentially other ACLs.

Mitigation and Prevention

Explore the strategies to mitigate and prevent CVE-2021-40346.

Immediate Steps to Take

Update HAProxy to the latest patched version that addresses the integer overflow vulnerability.
Monitor network traffic for any signs of attempted HTTP request smuggling attacks.
Implement network-level defenses to detect and block suspicious traffic patterns.

Long-Term Security Practices

Conduct regular security assessments and vulnerability scans on your network infrastructure.
Educate system administrators and developers about secure coding practices and the risks associated with integer overflows.

Patching and Updates

Stay informed about security advisories from HAProxy and promptly apply patches to address known vulnerabilities.