CVE-2020-8833 Information

Description

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.

CVSS Vector

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N

Reference

https://bugs.launchpad.net/ubuntu/+source/apport/+bug/1862933 https://usn.ubuntu.com/4315-1/ https://usn.ubuntu.com/4315-2/

Attack Complexity

HIGH

Privileges Required

LOW

User Interaction Required

LOW

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

HIGH

Availability Impact

NONE

Base Score

NONE

Base Severity

4.7