Ubuntu 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 the affected package squashfs-tools to the latest version.

Vulnerable software versions

Ubuntu: 18.04 - 21.04

squashfs-tools (Ubuntu package): before 1:4.4-2ubuntu0.1

External links

http://ubuntu.com/security/notices/USN-5057-1

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.