August 2023 Archives

Sat 05 Aug 2023 01:24:26 PM EEST

GNOME Files silently extracts setuid files from ZIP archives

Affected: GNOME Files 43.4 (nautilus) on fedora 37


If an user A opens in GNOME files zip archive containing setuid file F, then F will be silently extracted to
a subdirectory of CWD.

If F is accessible by hostile local user B and B executes F, then F will be executed as from user A.

tar(1) and unzip(1) are not vulnerable to this attack.

Session for creating the ZIP. After that just open in GNOME files.

[joro@fedora ~]$ umask
[joro@fedora 2]$ mkdir /tmp/2 ; cd /tmp/2 ; echo hi > F ; chmod +xs F
[joro@fedora 2]$ zip f F ; zipinfo f
Zip file size: 155 bytes, number of entries: 1
-rwsr-sr-x  3.0 unx        3 tx stor 23-Aug-05 12:38 F
[joro@fedora 2]$ ls -ld /tmp/2/
drwxr-xr-x. 2 joro joro 80 Aug  5 11:20 /tmp/2/
[joro@fedora 2]$

Posted by joro | Permanent link