CVE-2021-42013 : Security Advisory and Response

Apache HTTP Server 2.4.49 and 2.4.50 are impacted by a critical path traversal and remote code execution vulnerability.

Understanding CVE-2021-42013

This CVE highlights a security flaw within Apache HTTP Server versions 2.4.49 and 2.4.50 leading to path traversal and potential code execution.

What is CVE-2021-42013?

CVE-2021-42013 is a critical vulnerability in Apache HTTP Server versions 2.4.49 and 2.4.50 due to an incomplete fix for a previous CVE (CVE-2021-41773). Attackers can exploit path traversal to access files outside configured directories, potentially allowing remote code execution.

The Impact of CVE-2021-42013

The vulnerability could permit attackers to perform path traversal attacks, accessing files outside designated directories, and potentially execute remote code if CGI scripts are enabled.

Technical Details of CVE-2021-42013

This section provides insights into the vulnerability's technical aspects.

Vulnerability Description

The fix for CVE-2021-41773 in Apache HTTP Server 2.4.50 was inadequate, enabling a path traversal exploit to access files beyond configured Alias-like directives.

Affected Systems and Versions

Affected Versions: Apache HTTP Server 2.4.49 and 2.4.50

Exploitation Mechanism

Attackers utilize path traversal to map URLs to files outside configured directories
If unprotected, requests can succeed, potentially leading to remote code execution

Mitigation and Prevention

Understand the necessary steps to mitigate and prevent exploitation.

Immediate Steps to Take

Apply security updates promptly
Configure proper file access permissions
Disable CGI scripts if not required

Long-Term Security Practices

Regular security assessments and audits
Monitor and restrict external access to sensitive directories
Implement principle of least privilege

Patching and Updates

Install patches provided by Apache Software Foundation
Stay informed about security advisories and updates from trusted sources