Vulnerability Name:

CVE-2020-8833 (CCN-180462)

Assigned:2020-02-12
Published:2020-02-12
Updated:2022-10-07
Summary: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 v3 Severity:4.7 Medium (CVSS v3.1 Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N)
4.1 Medium (Temporal CVSS v3.1 Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C)
Exploitability Metrics:Attack Vector (AV): Local
Attack Complexity (AC): High
Privileges Required (PR): Low
User Interaction (UI): None
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): High
Integrity (I): None
Availibility (A): None
7.8 High (CCN CVSS v3.1 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)
6.8 Medium (CCN Temporal CVSS v3.1 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C)
Exploitability Metrics:Attack Vector (AV): Local
Attack Complexity (AC): Low
Privileges Required (PR): Low
User Interaction (UI): None
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): High
Integrity (I): High
Availibility (A): High
CVSS v2 Severity:1.9 Low (CVSS v2 Vector: AV:L/AC:M/Au:N/C:P/I:N/A:N)
Exploitability Metrics:Access Vector (AV): Local
Access Complexity (AC): Medium
Authentication (Au): None
Impact Metrics:Confidentiality (C): Partial
Integrity (I): None
Availibility (A): None
6.8 Medium (CCN CVSS v2 Vector: AV:L/AC:L/Au:S/C:C/I:C/A:C)
Exploitability Metrics:Access Vector (AV): Local
Access Complexity (AC): Low
Athentication (Au): Single_Instance
Impact Metrics:Confidentiality (C): Complete
Integrity (I): Complete
Availibility (A): Complete
Vulnerability Type:CWE-367
Vulnerability Consequences:Gain Privileges
References:Source: MITRE
Type: CNA
CVE-2020-8833

Source: CCN
Type: Launchpad Bug #1862933
Apport crash report & cron script TOCTTOU

Source: CONFIRM
Type: Exploit, Third Party Advisory
https://bugs.launchpad.net/ubuntu/+source/apport/+bug/1862933

Source: XF
Type: UNKNOWN
ubuntu-cve20208833-priv-esc(180462)

Source: CCN
Type: Ubuntu Web site
Apport package

Source: CONFIRM
Type: Third Party Advisory
https://usn.ubuntu.com/4315-1/

Source: UBUNTU
Type: Third Party Advisory
USN-4315-2

Source: CCN
Type: WhiteSource Vulnerability Database
CVE-2020-8833

Vulnerable Configuration:Configuration 1:
  • cpe:/o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*
  • OR cpe:/o:canonical:ubuntu_linux:14.04:*:*:*:esm:*:*:*
  • OR cpe:/o:canonical:ubuntu_linux:19.10:*:*:*:*:*:*:*
  • OR cpe:/o:canonical:ubuntu_linux:16.04:*:*:*:esm:*:*:*

    • Configuration 2:
  • cpe:/a:apport_project:apport:-:*:*:*:*:*:*:*

    • * Denotes that component is vulnerable
    BACK
    canonical ubuntu linux 18.04
    canonical ubuntu linux 14.04
    canonical ubuntu linux 19.10
    canonical ubuntu linux 16.04
    apport_project apport -