CVE-2021-3738 : Security Advisory and Response

In DCE/RPC, sharing handles (cookies for resource state) between multiple connections via 'association groups' can lead to a user-after-free vulnerability affecting Samba versions. This could result in a crash or potentially allow unauthorized privileged access.

Understanding CVE-2021-3738

This section covers what CVE-2021-3738 entails, its impact, technical details, and mitigation strategies.

What is CVE-2021-3738?

CVE-2021-3738 allows sharing handles referencing connections to the sam.ldb database, potentially leading to unauthorized system access.

The Impact of CVE-2021-3738

The vulnerability could result in a crash or enable attackers to gain more privileged access by manipulating user state pointers.

Technical Details of CVE-2021-3738

Understanding the vulnerability in detail to comprehend its exploitation, affected systems, and the mechanism behind the issue.

Vulnerability Description

The flaw stems from leaving the database pointing at an invalid 'struct session_info' after a connection ends, leading to a user-after-free scenario.

Affected Systems and Versions

Samba versions 4.0 onwards are vulnerable, with fixes available in versions 4.15.2, 4.14.10, and 4.13.14.

Exploitation Mechanism

Attackers could exploit the user-after-free condition to crash the system or potentially manipulate user state pointers for unauthorized access.

Mitigation and Prevention

Guidance on immediate actions to secure systems and establish long-term security practices.

Immediate Steps to Take

Ensure systems are updated with the latest Samba patches or configurations to mitigate the CVE-2021-3738 vulnerability.

Long-Term Security Practices

Regularly monitor for security advisories and apply patches promptly to prevent exploitation of known vulnerabilities.

Patching and Updates

Stay informed about security updates from Samba and related sources to address vulnerabilities promptly.