CVE-2020-11934

Sandbox escape vulnerability via snapctl user-open (xdg-open)

Severity Score

5.9

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

It was discovered that snapctl user-open allowed altering the $XDG_DATA_DIRS environment variable when calling the system xdg-open. OpenURL() in usersession/userd/launcher.go would alter $XDG_DATA_DIRS to append a path to a directory controlled by the calling snap. A malicious snap could exploit this to bypass intended access restrictions to control how the host system xdg-open script opens the URL and, for example, execute a script shipped with the snap without confinement. This issue did not affect Ubuntu Core systems. Fixed in snapd versions 2.45.1ubuntu0.2, 2.45.1+18.04.2 and 2.45.1+20.04.2.

Se detectó que snapctl user-open permitía alterar la variable de entorno $XDG_DATA_DIRS cuando se llama al sistema xdg-open. La función OpenURL() en el archivo usersession/userd/launcher.go alteraría $XDG_DATA_DIRS para agregar una ruta a un directorio controlado por el complemento de llamada. Un complemento malicioso podría explotar esto para omitir las restricciones de acceso previstas para controlar cómo el script xdg-open del sistema host abre la URL y, por ejemplo, ejecuta un script enviado con el complemento sin confinamiento. Este problema no afectó a los sistemas Ubuntu Core. Corregido en las versiones snapd 2.45.1ubuntu0.2, 2.45.1+18.04.2 y 2.45.1+20.04.2

*Credits: James Henstridge

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

Required

Scope

Changed

Confidentiality

None

Integrity

High

Availability

None

Attack Vector

Local

Attack Complexity

Medium

Authentication

None

Confidentiality

None

Integrity

Partial

Availability

None

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2020-04-20 CVE Reserved
2020-07-15 CVE Published
2023-03-08 EPSS Updated
2024-09-17 CVE Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-668: Exposure of Resource to Wrong Sphere

CAPEC

References (2)

URL	Tag	Source
https://launchpad.net/bugs/1880085	Third Party Advisory

URL	Date	SRC

URL	Date	SRC

URL	Date	SRC
https://ubuntu.com/USN-4424-1	2020-08-05

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
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