CVE-2018-12026 Explained : Impact and Mitigation

Phusion Passenger versions 5.3.x before 5.3.2 allows malicious Passenger-managed applications to replace critical files or directories with symlinks, potentially leading to unauthorized access and privilege escalation.

Understanding CVE-2018-12026

In the process of initiating a harmful Passenger-managed application, SpawningKit in Phusion Passenger versions 5.3.x prior to 5.3.2 permits these applications to substitute critical files or directories in the communication directory for symlinks. Consequently, this can lead to unauthorized access to information and an elevation of privileges.

What is CVE-2018-12026?

This CVE describes a vulnerability in Phusion Passenger versions 5.3.x before 5.3.2 that allows malicious applications to replace essential files or directories with symlinks, potentially resulting in unauthorized access and privilege escalation.

The Impact of CVE-2018-12026

The exploitation of this vulnerability can lead to unauthorized access to sensitive information and an elevation of privileges within the affected system.

Technical Details of CVE-2018-12026

Phusion Passenger versions 5.3.x before 5.3.2 are susceptible to the following:

Vulnerability Description

During the spawning of a malicious Passenger-managed application, SpawningKit in Phusion Passenger 5.3.x before 5.3.2 allows such applications to replace key files or directories in the spawning communication directory with symlinks. This could result in arbitrary reads and writes, leading to information disclosure and privilege escalation.

Affected Systems and Versions

Phusion Passenger versions 5.3.x before 5.3.2

Exploitation Mechanism

The vulnerability allows malicious Passenger-managed applications to replace critical files or directories with symlinks, potentially granting unauthorized access and privilege escalation.

Mitigation and Prevention

To address CVE-2018-12026, consider the following steps:

Immediate Steps to Take

Upgrade Phusion Passenger to version 5.3.2 or later to mitigate the vulnerability.
Monitor for any unauthorized access or unusual activities on the system.

Long-Term Security Practices

Regularly update and patch software to prevent known vulnerabilities.
Implement access controls and least privilege principles to limit the impact of potential security breaches.

Patching and Updates

Apply security patches and updates provided by Phusion to ensure the system is protected against known vulnerabilities.