CVE-2020-11931

Ubuntu modifications to pulseaudio to provide snap security enforcement could be unloaded

Severity Score

3.3

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

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 issue affects: pulseaudio 1:8.0 versions prior to 1:8.0-0ubuntu3.12; 1:11.1 versions prior to 1:11.1-1ubuntu7.7; 1:13.0 versions prior to 1:13.0-1ubuntu1.2; 1:13.99.1 versions prior to 1:13.99.1-1ubuntu3.2;

Una modificación específica de Ubuntu para Pulseaudio para proporcionar mediación de seguridad para aplicaciones empaquetadas de Snap se encontró que presenta una omisión de la restricción de acceso prevista para los snaps que conecta cualquiera pulseaudio, audio-playback o audio-record mediante la descarga del módulo de la política de snap de pulseaudio. Este problema afecta a: pulseaudio versiones 1:8.0 anteriores a 1:8.0-0ubuntu3.12; versiones 1:11.1 anteriores a 1:11.1-1ubuntu7.7; versiones 1:13.0 anteriores a 1:13.0-1ubuntu1.2; versiones 1:13.99.1 anteriores a 1:13.99.1-1ubuntu3.2;

PulseAudio in Ubuntu contains additional functionality to mediate audio recording for snap packages and it was discovered that this functionality did not mediate PulseAudio module unloading. An attacker-controlled snap with only the audio-playback interface connected could exploit this to bypass access controls and record audio.

*Credits: James Henstridge

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

None

Attack Vector

Local

Attack Complexity

Low

Authentication

None

Confidentiality

Partial

Integrity

None

Availability

None

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2020-04-20 CVE Reserved
2020-05-12 CVE Published
2024-09-17 CVE Updated
2025-03-30 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-284: Improper Access Control
CWE-668: Exposure of Resource to Wrong Sphere

CAPEC

References (2)

URL	Tag	Source
https://forum.snapcraft.io/t/audio-switcher-pulseaudio-interface-auto-connect-request/16648/3	Third Party Advisory

URL	Date	SRC

URL	Date	SRC

URL	Date	SRC
https://usn.ubuntu.com/4355-1	2020-05-19

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Pulseaudio Search vendor "Pulseaudio"		Pulseaudio Search vendor "Pulseaudio" for product "Pulseaudio"				<= 1.8.0 Search vendor "Pulseaudio" for product "Pulseaudio" and version " <= 1.8.0"		-		Affected
Canonical Search vendor "Canonical"		Ubuntu Linux Search vendor "Canonical" for product "Ubuntu Linux"				16.04 Search vendor "Canonical" for product "Ubuntu Linux" and version "16.04"		lts		Affected
Canonical Search vendor "Canonical"		Ubuntu Linux Search vendor "Canonical" for product "Ubuntu Linux"				18.04 Search vendor "Canonical" for product "Ubuntu Linux" and version "18.04"		lts		Affected
Canonical Search vendor "Canonical"		Ubuntu Linux Search vendor "Canonical" for product "Ubuntu Linux"				19.10 Search vendor "Canonical" for product "Ubuntu Linux" and version "19.10"		-		Affected
Canonical Search vendor "Canonical"		Ubuntu Linux Search vendor "Canonical" for product "Ubuntu Linux"				20.04 Search vendor "Canonical" for product "Ubuntu Linux" and version "20.04"		lts		Affected