CVE-2020-11931 Explained : Impact and Mitigation

An Ubuntu-specific modification to Pulseaudio to provide security mediation for Snap-packaged applications was found to have a bypass of intended access restriction for snaps which plugs any of pulseaudio, audio-playback or audio-record via unloading the pulseaudio snap policy module. This vulnerability affects multiple versions of Pulseaudio on Ubuntu.

Understanding CVE-2020-11931

This CVE involves a security issue in Pulseaudio on Ubuntu that could allow unauthorized access to certain functionalities.

What is CVE-2020-11931?

CVE-2020-11931 is a vulnerability in Pulseaudio on Ubuntu that enables a bypass of intended access restrictions for Snap-packaged applications, potentially leading to unauthorized access to specific functionalities.

The Impact of CVE-2020-11931

The vulnerability could allow malicious actors to bypass security restrictions and gain unauthorized access to pulseaudio, audio-playback, or audio-record functionalities on affected systems.

Technical Details of CVE-2020-11931

This section provides more in-depth technical information about the vulnerability.

Vulnerability Description

The issue arises from an Ubuntu-specific modification to Pulseaudio, which fails to enforce security restrictions properly, allowing unauthorized unloading of the pulseaudio snap policy module.

Affected Systems and Versions

Pulseaudio 1:8.0 versions prior to 1:8.0-0ubuntu3.12
Pulseaudio 1:11.1 versions prior to 1:11.1-1ubuntu7.7
Pulseaudio 1:13.0 versions prior to 1:13.0-1ubuntu1.2
Pulseaudio 1:13.99.1 versions prior to 1:13.99.1-1ubuntu3.2

Exploitation Mechanism

The vulnerability can be exploited by unloading the pulseaudio snap policy module, which circumvents the intended access restrictions, allowing unauthorized access to certain functionalities.

Mitigation and Prevention

To address CVE-2020-11931, follow these mitigation strategies:

Immediate Steps to Take

Update Pulseaudio to the patched versions to mitigate the vulnerability.
Monitor system logs for any suspicious activities related to Pulseaudio.

Long-Term Security Practices

Regularly update software and apply security patches promptly.
Implement least privilege access controls to limit unauthorized access to critical system components.

Patching and Updates

Apply the necessary patches provided by Canonical to fix the security vulnerability in Pulseaudio.