CVE-2019-11831 Explained : Impact and Mitigation

The TYPO3 package PharStreamWrapper (phar-stream-wrapper) versions 2.x before 2.1.1 and 3.x before 3.1.1 is vulnerable to directory traversal, allowing attackers to bypass protection mechanisms.

Understanding CVE-2019-11831

This CVE highlights a security vulnerability in the PharStreamWrapper package used in TYPO3.

What is CVE-2019-11831?

The vulnerability in PharStreamWrapper allows attackers to exploit directory traversal, circumventing deserialization protection.

The Impact of CVE-2019-11831

The vulnerability enables attackers to manipulate URLs to access unauthorized directories, potentially leading to unauthorized data access or code execution.

Technical Details of CVE-2019-11831

PharStreamWrapper's security flaw is detailed below.

Vulnerability Description

The issue arises from inadequate prevention of directory traversal in PharStreamWrapper, facilitating bypassing of deserialization protection.

Affected Systems and Versions

TYPO3 package PharStreamWrapper 2.x versions prior to 2.1.1
TYPO3 package PharStreamWrapper 3.x versions prior to 3.1.1

Exploitation Mechanism

Attackers can exploit the vulnerability by manipulating URLs, such as using 'phar:///path/bad.phar/../good.phar'.

Mitigation and Prevention

Protect your systems from CVE-2019-11831 with the following measures.

Immediate Steps to Take

Apply the latest security patches provided by TYPO3.
Monitor and restrict external access to vulnerable systems.
Implement network-level security controls to detect and block malicious traffic.

Long-Term Security Practices

Regularly update and patch software to address known vulnerabilities.
Conduct security assessments and penetration testing to identify and remediate weaknesses.
Educate users and administrators on secure coding practices and threat awareness.

Patching and Updates

Ensure timely installation of security updates and patches released by TYPO3 to mitigate the CVE-2019-11831 vulnerability.