CVE-2020-8833 Detail

Current 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.


View Analysis Description

Severity



CVSS 3.x Severity and Metrics:

NIST CVSS score
NIST: NVD
Base Score:  4.7 MEDIUM
Vector:  CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N

Nist CVSS score does not match with CNA score
CNA:  Canonical Ltd.
Base Score:  5.6 MEDIUM
Vector:  CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N


NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.

Note: It is possible that the NVD CVSS may not match that of the CNA. The most common reason for this is that publicly available information does not provide sufficient detail or that information simply was not available at the time the CVSS vector string was assigned.

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Hyperlink Resource
https://bugs.launchpad.net/ubuntu/+source/apport/+bug/1862933 Exploit  Third Party Advisory 
https://usn.ubuntu.com/4315-1/ Third Party Advisory 
https://usn.ubuntu.com/4315-2/

Weakness Enumeration

CWE-ID CWE Name Source
CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition cwe source acceptance level NIST   Reference acceptance level Canonical Ltd.  

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Change History

3 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2020-8833
NVD Published Date:
04/22/2020
NVD Last Modified:
06/24/2020
Source:
MITRE