Debian update for squashfs-tools

1) Path traversal

EUVDB-ID: #VU56306

Risk: Medium

CVSSv3.1: 7.1 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-40153

CWE-ID: CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

Exploit availability: No

Description

The vulnerability allows a remote user to compromise the affected system.

The vulnerability exists due to input validation error when processing directory traversal sequences within the squashfs_opendir in unsquash-1.c. A remote user can store the filename in the directory entry, which later is used by unsquashfs to create the new file during the unsquash. As a result, it is possible to write files to locations outside of the destination.

Mitigation

Update squashfs-tools package to one of the following versions: 1:4.3-12+deb10u1, 1:4.4-2+deb11u1.

Vulnerable software versions

squashfs-tools (Debian package): 1:4.0-1 - 1:4.4-2

External links

http://www.debian.org/security/2021/dsa-4967

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.