CVE-2020-8831

World writable root owned lock file created in user controllable location

Severity Score

5.5

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

Apport creates a world writable lock file with root ownership in the world writable /var/lock/apport directory. If the apport/ directory does not exist (this is not uncommon as /var/lock is a tmpfs), it will create the directory, otherwise it will simply continue execution using the existing directory. This allows for a symlink attack if an attacker were to create a symlink at /var/lock/apport, changing apport's lock file location. This file could then be used to escalate privileges, for example. Fixed in versions 2.20.1-0ubuntu2.23, 2.20.9-0ubuntu7.14, 2.20.11-0ubuntu8.8 and 2.20.11-0ubuntu22.

Apport crea un archivo de bloqueo de tipo world writable con propiedad root en el directorio /var/lock/apport de tipo world writable. Si el directorio apport/ no existe (esto no es raro ya que /var/lock es un tmpfs), creará el directorio, de lo contrario, simplemente continuará la ejecución usando el directorio existente. Esto permite un ataque de tipo symlink si un atacante creara un enlace simbólico en el directorio /var/lock/apport, cambiando la ubicación del archivo de bloqueo de apport. Este archivo podría ser utilizado para escalar privilegios, por ejemplo. Corregido en las versiones 2.20.1-0ubuntu2.23, 2.20.9-0ubuntu7.14, 2.20.11-0ubuntu8.8 y 2.20.11-0ubuntu22.

*Credits: Maximilien Bourgeteau

CVSS Scores

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

High

Availability

None

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Changed

Confidentiality

None

Integrity

High

Availability

None

Attack Vector

Local

Attack Complexity

Low

Authentication

None

Confidentiality

None

Integrity

Partial

Availability

None

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2020-02-10 CVE Reserved
2020-04-02 CVE Published
2023-03-08 EPSS Updated
2024-09-16 CVE Updated
2024-09-16 First Exploit
---------- Exploited in Wild
---------- KEV Due Date

CWE

CWE-59: Improper Link Resolution Before File Access ('Link Following')
CWE-379: Creation of Temporary File in Directory with Insecure Permissions

CAPEC

References (3)

URL	Tag	Source
https://usn.ubuntu.com/4315-1	Third Party Advisory

URL	Date	SRC
https://launchpad.net/bugs/1862348	2024-09-16

URL	Date	SRC

URL	Date	SRC
https://usn.ubuntu.com/4315-2	2022-10-07

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"				14.04 Search vendor "Canonical" for product "Ubuntu Linux" and version "14.04"		esm		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"		esm		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
Apport Project Search vendor "Apport Project"		Apport Search vendor "Apport Project" for product "Apport"				-		-		Affected