CVE-2020-8833
Publication date 2 April 2020
Last updated 24 July 2024
Ubuntu priority
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.
Mitigation
This ability to exploit this is likely mitigated by the Ubuntu default of fs.protected_symlinks=1
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| apport | 20.04 LTS focal |
Fixed 2.20.11-0ubuntu22
|
| 18.04 LTS bionic |
Fixed 2.20.9-0ubuntu7.14
|
|
| 16.04 LTS xenial |
Fixed 2.20.1-0ubuntu2.23
|
|
| 14.04 LTS trusty |
Fixed 2.14.1-0ubuntu3.29+esm4
|
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Get Ubuntu ProSeverity score breakdown
| Parameter | Value |
|---|---|
| Base score |
4.7 · Medium
|
| Attack vector | Local |
| Attack complexity | High |
| Privileges required | Low |
| User interaction | None |
| Scope | Unchanged |
| Confidentiality | High |
| Integrity impact | None |
| Availability impact | None |
| Vector | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N |
References
Related Ubuntu Security Notices (USN)
- USN-4315-2
- Apport vulnerabilities
- 15 June 2020
- USN-4315-1
- Apport vulnerabilities
- 2 April 2020