CVE-2019-13464 : Exploit Details and Defense Strategies

OWASP ModSecurity Core Rule Set (CRS) 3.0.2 has a vulnerability where the use of X.Filename instead of X_Filename can potentially bypass certain PHP Script Uploads rules.

Understanding CVE-2019-13464

What is CVE-2019-13464?

An issue was discovered in OWASP ModSecurity Core Rule Set (CRS) 3.0.2. The incorrect use of X.Filename instead of X_Filename can lead to bypassing PHP Script Uploads rules due to PHP's automatic conversion of dots into underscores in specific contexts.

The Impact of CVE-2019-13464

This vulnerability can be exploited to bypass certain security rules, potentially allowing malicious actors to upload and execute unauthorized PHP scripts on affected systems.

Technical Details of CVE-2019-13464

Vulnerability Description

The vulnerability in OWASP ModSecurity CRS 3.0.2 arises from the incorrect usage of X.Filename, enabling the circumvention of PHP Script Uploads rules.

Affected Systems and Versions

Product: OWASP ModSecurity Core Rule Set (CRS) 3.0.2
Vendor: N/A
Versions: N/A

Exploitation Mechanism

The issue occurs due to PHP's automatic conversion of dots into underscores in situations where dots are not permitted, potentially allowing attackers to evade security measures.

Mitigation and Prevention

Immediate Steps to Take

Apply the necessary patches or updates provided by OWASP ModSecurity to address this vulnerability.
Monitor for any unauthorized PHP script uploads on the system.

Long-Term Security Practices

Regularly update and maintain the OWASP ModSecurity Core Rule Set to ensure the latest security fixes are in place.
Implement strict file upload validation mechanisms to prevent the execution of unauthorized scripts.

Patching and Updates

Ensure that you regularly check for updates and patches from OWASP ModSecurity to mitigate the risk of this vulnerability.