title: Apport race condition in crash report permissions
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.
problem types: CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition
affected:
{
product: Apport
vendor: Canonical
versions:
lessThan: 2.20.1-0ubuntu2.23, status: affected, version: 2.20.1, versionType: custom
lessThan: 2.20.9-0ubuntu7.14, status: affected, version: 2.20.9, versionType: custom
changes: [at: 2.20.11-0ubuntu22, status: unaffected], lessThan: 2.20.11-0ubuntu8.8, status: affected, version: 2.20.11, versionType: custom
}
metrics:
cvssV3_1: [
attackComplexity: HIGH
attackVector: LOCAL
availabilityImpact: NONE
baseScore: 5.6
baseSeverity: MEDIUM
confidentialityImpact: HIGH
integrityImpact: NONE
privilegesRequired: LOW
scope: CHANGED
userInteraction: NONE
vectorString: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N
version: 3.1
]