CVE-2019-16905 : What You Need to Know

OpenSSH Pre-Authentication Integer Overflow Vulnerability

Understanding CVE-2019-16905

What is CVE-2019-16905?

The CVE-2019-16905 is a pre-authentication integer overflow vulnerability found in OpenSSH versions 7.7 through 7.9 and 8.x before 8.1. This vulnerability arises when an experimental key type is utilized during OpenSSH compilation. Exploiting this flaw with a manipulated XMSS key can lead to memory corruption and local code execution due to issues in the XMSS key parsing algorithm.

The Impact of CVE-2019-16905

This vulnerability can result in memory corruption and local code execution, posing a significant security risk to systems using affected versions of OpenSSH.

Technical Details of CVE-2019-16905

Vulnerability Description

The vulnerability stems from an integer overflow issue in the XMSS key parsing algorithm within OpenSSH, specifically affecting versions 7.7 through 7.9 and 8.x before 8.1.

Affected Systems and Versions

OpenSSH versions 7.7 through 7.9
OpenSSH versions 8.x before 8.1

Exploitation Mechanism

The vulnerability can be exploited by using a manipulated XMSS key, triggering memory corruption and enabling local code execution.

Mitigation and Prevention

Immediate Steps to Take

Disable the use of the experimental XMSS key type in OpenSSH configurations.
Regularly monitor for security advisories and updates from OpenSSH.

Long-Term Security Practices

Implement strong access controls and authentication mechanisms.
Conduct regular security assessments and audits to identify vulnerabilities.
Stay informed about security best practices and updates in the cybersecurity landscape.

Patching and Updates

Apply patches and updates provided by OpenSSH to address the vulnerability and enhance system security.