Arbitrary File Write via Archive Extraction (Zip Slip) Affecting github.com/snapcore/snapd/overlord/snapshotstate/backend package, versions <2.58.1


Severity

Recommended
0.0
medium
0
10

CVSS assessment by Snyk's Security Team. Learn more

Threat Intelligence

Exploit Maturity
Proof of Concept

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  • Snyk IDSNYK-GOLANG-GITHUBCOMSNAPCORESNAPDOVERLORDSNAPSHOTSTATEBACKEND-3172910
  • published15 Dec 2022
  • disclosed12 Dec 2022
  • creditSam Sanoop of Snyk Security Team

Introduced: 12 Dec 2022

CVE NOT AVAILABLE CWE-29  (opens in a new tab)
First added by Snyk

How to fix?

Upgrade github.com/snapcore/snapd/overlord/snapshotstate/backend to version 2.58.1 or higher.

Overview

github.com/snapcore/snapd/overlord/snapshotstate/backend is a The snapd and snap tools enable systems to work with .snap files.

Affected versions of this package are vulnerable to Arbitrary File Write via Archive Extraction (Zip Slip). When importing a snapshot (https://snapcraft.io/docs/snapshots), it is possible for a malcious snapshot tar file to traverse a user's system and overwrite any files on the system, through relative paths e.g. "../../"

Details

It is exploited using a specially crafted zip archive, that holds path traversal filenames. When exploited, a filename in a malicious archive is concatenated to the target extraction directory, which results in the final path ending up outside of the target folder. For instance, a zip may hold a file with a "../../file.exe" location and thus break out of the target folder. If an executable or a configuration file is overwritten with a file containing malicious code, the problem can turn into an arbitrary code execution issue quite easily.

The following is an example of a zip archive with one benign file and one malicious file. Extracting the malicous file will result in traversing out of the target folder, ending up in /root/.ssh/ overwriting the authorized_keys file:


+2018-04-15 22:04:29 ..... 19 19 good.txt

+2018-04-15 22:04:42 ..... 20 20 ../../../../../../root/.ssh/authorized_keys

CVSS Base Scores

version 3.1