CVEs-PoC/2020/CVE-2020-8833.md

### [CVE-2020-8833](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-8833)
![](https://img.shields.io/static/v1?label=Product&message=Apport&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=2.20.1%3C%202.20.1-0ubuntu2.23%20&color=brighgreen)
![](https://img.shields.io/static/v1?label=Vulnerability&message=CWE-367%20Time-of-check%20Time-of-use%20(TOCTOU)%20Race%20Condition&color=brighgreen)

### 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.

### POC

#### Reference
- https://bugs.launchpad.net/ubuntu/+source/apport/+bug/1862933

#### Github
- https://github.com/Live-Hack-CVE/CVE-2020-8833