init_tmp in TeeJee.FileSystem.vala in Timeshift before 20.03 unsafely reuses a preexisting temporary directory in the predictable location /tmp/timeshift. It follows symlinks in this location or uses directories owned by unprivileged users. Because Timeshift also executes scripts under this location, an attacker can attempt to win a race condition to replace scripts created by Timeshift with attacker-controlled scripts. Upon success, an attacker-controlled script is executed with full root privileges. This logic is practically always triggered when Timeshift runs regardless of the command-line arguments used.
The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.
| Link | Tags |
|---|---|
| https://bugzilla.suse.com/show_bug.cgi?id=1165802 | issue tracking third party advisory |
| https://github.com/teejee2008/timeshift/commit/335b3d5398079278b8f7094c77bfd148b315b462 | third party advisory patch |
| https://github.com/teejee2008/timeshift/releases/tag/v20.03 | third party advisory release notes |
| http://www.openwall.com/lists/oss-security/2020/03/06/3 | third party advisory mailing list |
| https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TXXYQFSZ5P6ZMNFIDBAQKBFZIR2T7ZLL/ | vendor advisory |
| https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SXDEPC52G46U6I7GLQNFLZXVSM7V2HYY/ | vendor advisory |
| https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/AAOFXT64CEUMJE3723JDJWTEQWQUCYMD/ | vendor advisory |
| https://usn.ubuntu.com/4312-1/ | third party advisory vendor advisory |