// For flags

CVE-2020-8833

Apport race condition in crash report permissions

Severity Score

4.7
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

1
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

Time-of-check Time-of-use Race Condition vulnerability on crash report ownership change in Apport allows for a possible privilege escalation opportunity. If fs.protected_symlinks is disabled, this can be exploited between the os.open and os.chown calls when the Apport cron script clears out crash files of size 0. A symlink with the same name as the deleted file can then be created upon which chown will be called, changing the file owner to root. Fixed in versions 2.20.1-0ubuntu2.23, 2.20.9-0ubuntu7.14, 2.20.11-0ubuntu8.8 and 2.20.11-0ubuntu22.

Una vulnerabilidad de Condición de Carrera de tipo Time-of-check Time-of-use en el cambio de propiedad del reporte de bloqueo en Apport, permite una posible oportunidad de escalada de privilegios. Si fs.protected_symlinks está deshabilitado, esto puede ser explotado entre las llamadas de os.open y os.chown cuando el script cron de Apport borra los archivos bloqueados de tamaño 0. Un enlace simbólico con el mismo nombre que el archivo eliminado puede entonces ser creado a partir de que chown sería llamado, cambiando el propietario del archivo a root. 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
High
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None
Attack Vector
Local
Attack Complexity
High
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
None
Availability
None
Attack Vector
Local
Attack Complexity
Medium
Authentication
None
Confidentiality
Partial
Integrity
None
Availability
None
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2020-02-10 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-367: Time-of-check Time-of-use (TOCTOU) Race Condition
CAPEC
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