CVE-2017-18188 : Security Advisory and Response

OpenRC opentmpfiles up to version 0.1.3 allows local users to gain ownership of any files by creating a hard link within a directory where "chown -R" will be executed.

Understanding CVE-2017-18188

If the fs.protected_hardlinks sysctl is disabled, this vulnerability enables local users to manipulate file ownership.

What is CVE-2017-18188?

OpenRC opentmpfiles through version 0.1.3, when fs.protected_hardlinks is off, allows users to take ownership of arbitrary files by creating hard links.

The Impact of CVE-2017-18188

This vulnerability can lead to unauthorized access and manipulation of sensitive files, potentially compromising system integrity.

Technical Details of CVE-2017-18188

OpenRC opentmpfiles vulnerability details.

Vulnerability Description

When fs.protected_hardlinks is disabled, local users can exploit the vulnerability to gain ownership of files through hard links.

Affected Systems and Versions

Product: n/a
Vendor: n/a
Versions affected: up to 0.1.3

Exploitation Mechanism

By creating a hard link within a directory where "chown -R" will be executed, local users can manipulate file ownership.

Mitigation and Prevention

Steps to address CVE-2017-18188

Immediate Steps to Take

Enable fs.protected_hardlinks sysctl to prevent unauthorized ownership changes.
Regularly monitor file ownership and permissions for any unauthorized changes.

Long-Term Security Practices

Implement the principle of least privilege to restrict user capabilities.
Conduct regular security audits to identify and address vulnerabilities.

Patching and Updates

Apply patches or updates provided by OpenRC to fix the vulnerability and enhance system security.