CVE-2020-8833 : Security Advisory and Response

A Time-of-check Time-of-use Race Condition vulnerability in Apport could lead to privilege escalation. Learn about the impact, affected systems, and mitigation steps.

Understanding CVE-2020-8833

This CVE involves a race condition in crash report permissions in Apport, affecting certain versions.

What is CVE-2020-8833?

The vulnerability allows privilege escalation by exploiting a race condition during crash report ownership change in Apport.

The Impact of CVE-2020-8833

CVSS Base Score: 5.6 (Medium Severity)
Attack Complexity: High
Attack Vector: Local
Confidentiality Impact: High
Integrity Impact: None
Privileges Required: Low
Scope: Changed

Technical Details of CVE-2020-8833

This section provides detailed technical information about the vulnerability.

Vulnerability Description

The vulnerability arises due to a race condition in crash report ownership change in Apport, allowing privilege escalation.

Affected Systems and Versions

Apport versions 2.20.1-0ubuntu2.23, 2.20.9-0ubuntu7.14, and 2.20.11-0ubuntu8.8 are affected.

Exploitation Mechanism

The vulnerability can be exploited when fs.protected_symlinks is disabled, between os.open and os.chown calls in the Apport cron script.

Mitigation and Prevention

Protect your systems from CVE-2020-8833 with these mitigation strategies.

Immediate Steps to Take

Enable fs.protected_symlinks to prevent exploitation.
Update Apport to the fixed versions.

Long-Term Security Practices

Regularly update and patch software to prevent vulnerabilities.
Implement least privilege access controls to limit potential damage.

Patching and Updates

Apply patches provided by Canonical to address the vulnerability.