CVE-2019-15316 Explained : Impact and Mitigation

Valve Steam Client for Windows up until 2019-08-20 has a vulnerability due to insecure folder permissions, allowing privilege escalation through a TOCTOU race condition.

Understanding CVE-2019-15316

The vulnerability in Valve Steam Client for Windows could be exploited for privilege escalation to NT AUTHORITY\SYSTEM.

What is CVE-2019-15316?

The Valve Steam Client for Windows up until 2019-08-20 suffers from insecure folder permissions, which can be exploited for privilege escalation to NT AUTHORITY\SYSTEM by exploiting the CreateMountPoint.exe and SetOpLock.exe components to take advantage of a TOCTOU race condition.

The Impact of CVE-2019-15316

The vulnerability allows attackers to escalate privileges to NT AUTHORITY\SYSTEM, potentially leading to unauthorized access and control over the affected system.

Technical Details of CVE-2019-15316

Valve Steam Client for Windows through 2019-08-20 has weak folder permissions, leading to privilege escalation via crafted use of CreateMountPoint.exe and SetOpLock.exe to leverage a TOCTOU race condition.

Vulnerability Description

The vulnerability arises from insecure folder permissions in the Valve Steam Client for Windows, enabling attackers to exploit a TOCTOU race condition for privilege escalation.

Affected Systems and Versions

Affected Product: Valve Steam Client for Windows
Affected Version: Up until 2019-08-20

Exploitation Mechanism

Attackers can exploit the CreateMountPoint.exe and SetOpLock.exe components to take advantage of the TOCTOU race condition, allowing them to escalate privileges to NT AUTHORITY\SYSTEM.

Mitigation and Prevention

It is crucial to take immediate steps to mitigate the risks posed by CVE-2019-15316 and implement long-term security practices.

Immediate Steps to Take

Apply security patches provided by Valve to address the vulnerability.
Monitor system logs for any suspicious activities indicating exploitation attempts.

Long-Term Security Practices

Regularly update and patch software to prevent known vulnerabilities.
Implement the principle of least privilege to restrict access rights and minimize the impact of potential security breaches.
Conduct regular security assessments and penetration testing to identify and address security weaknesses.
Educate users on safe computing practices to prevent social engineering attacks.

Patching and Updates

Valve should release patches to fix the insecure folder permissions in the Valve Steam Client for Windows and prevent privilege escalation vulnerabilities.