CVE-2021-41091

Insufficiently restricted permissions on data directory in Docker Engine

Severity Score

6.3

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

Moby is an open-source project created by Docker to enable software containerization. A bug was found in Moby (Docker Engine) where the data directory (typically `/var/lib/docker`) contained subdirectories with insufficiently restricted permissions, allowing otherwise unprivileged Linux users to traverse directory contents and execute programs. When containers included executable programs with extended permission bits (such as `setuid`), unprivileged Linux users could discover and execute those programs. When the UID of an unprivileged Linux user on the host collided with the file owner or group inside a container, the unprivileged Linux user on the host could discover, read, and modify those files. This bug has been fixed in Moby (Docker Engine) 20.10.9. Users should update to this version as soon as possible. Running containers should be stopped and restarted for the permissions to be fixed. For users unable to upgrade limit access to the host to trusted users. Limit access to host volumes to trusted containers.

Moby es un proyecto de código abierto creado por Docker para permitir la contención de software. Se encontró un error en Moby (Docker Engine) en el que el directorio de datos (normalmente "/var/lib/docker") contenía subdirectorios con permisos insuficientemente restringidos, lo que permitía a usuarios de Linux no privilegiados saltar el contenido del directorio y ejecutar programas. Cuando los contenedores incluían programas ejecutables con bits de permiso extendidos (como "setuid"), los usuarios no privilegiados de Linux podían detectar y ejecutar esos programas. Cuando el UID de un usuario de Linux no privilegiados en el host colisionaba con el propietario o el grupo de un archivo dentro de un contenedor, el usuario de Linux no privilegiados en el host podía descubrir, leer y modificar esos archivos. Este bug ha sido corregido en Moby (Docker Engine) versión 20.10.9. Usuarios deberían actualizar a esta versión lo antes posible. Los contenedores en ejecución deben ser detenidos y reiniciados para que los permisos sean corregidos. Para usuarios que no puedan actualizar, limite el acceso al host a usuarios confiables. Limite el acceso a los volúmenes del host a los contenedores confiables

*Credits: N/A

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

Low

Attack Vector

Local

Attack Complexity

Low

Authentication

None

Confidentiality

Partial

Integrity

Partial

Availability

Partial

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2021-09-15 CVE Reserved
2021-10-04 CVE Published
2023-03-08 EPSS Updated
2023-05-20 First Exploit
2024-08-04 CVE Updated
---------- Exploited in Wild
---------- KEV Due Date

CWE

CWE-281: Improper Preservation of Permissions
CWE-732: Incorrect Permission Assignment for Critical Resource

CAPEC

References (7)

URL	Tag	Source
https://cert-portal.siemens.com/productcert/pdf/ssa-222547.pdf	X_refsource_confirm
https://github.com/moby/moby/security/advisories/GHSA-3fwx-pjgw-3558	Third Party Advisory

URL	Date	SRC
https://github.com/UncleJ4ck/CVE-2021-41091	2023-05-20
https://github.com/jrbH4CK/CVE-2021-41091	2024-05-10

URL	Date	SRC
https://github.com/moby/moby/commit/f0ab919f518c47240ea0e72d0999576bb8008e64	2023-11-07

URL	Date	SRC
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/B5Q6G6I4W5COQE25QMC7FJY3I3PAYFBB	2023-11-07
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZNFADTCHHYWVM6W4NJ6CB4FNFM2VMBIB	2023-11-07

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Mobyproject Search vendor "Mobyproject"		Moby Search vendor "Mobyproject" for product "Moby"				< 20.10.9 Search vendor "Mobyproject" for product "Moby" and version " < 20.10.9"		-		Affected
Fedoraproject Search vendor "Fedoraproject"		Fedora Search vendor "Fedoraproject" for product "Fedora"				34 Search vendor "Fedoraproject" for product "Fedora" and version "34"		-		Affected
Fedoraproject Search vendor "Fedoraproject"		Fedora Search vendor "Fedoraproject" for product "Fedora"				35 Search vendor "Fedoraproject" for product "Fedora" and version "35"		-		Affected