Vulnerability · Published Apr 22, 2020 · Assigned by canonical

CVE-2020-8833Apport race condition in crash report permissions

Medium 5.6

In plain English

A medium-severity security flaw in Apport from Canonical. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 28% of all known vulnerabilities).

Severity (CVSS 3.1)5.6Medium

Exploit odds (30 days)0.3%top 72.0% of all CVEs

Exploited in the wildNo reportsnot in CISA KEV

Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

Vendor	Product	Versions
Canonical	Apport	2.20.1 – before 2.20.1-0ubuntu2.232.20.9 – before 2.20.9-0ubuntu7.142.20.11 – before 2.20.11-0ubuntu8.8

Weakness: CWE-367 · Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N

References

https://usn.ubuntu.com/4315-1/ x_refsource_CONFIRM
https://bugs.launchpad.net/ubuntu/+source/apport/+bug/1862933 x_refsource_CONFIRM
USN-4315-2 vendor-advisory, x_refsource_UBUNTU