Arbitrary File Write via Archive Extraction (Zip Slip) Affecting decompress-tar package, versions *


0.0
medium

Snyk CVSS

    Attack Complexity High
    Scope Changed
    Confidentiality High

    Threat Intelligence

    Exploit Maturity Proof of concept
    EPSS 0.62% (79th percentile)
Expand this section
NVD
9.8 critical

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications
  • Snyk ID SNYK-JS-DECOMPRESSTAR-559095
  • published 27 Feb 2020
  • disclosed 15 Oct 2019
  • credit Oscar Arnflo

How to fix?

There is no fixed version for decompress-tar.

Overview

decompress-tar is a tar plugin for decompress.

Affected versions of this package are vulnerable to Arbitrary File Write via Archive Extraction (Zip Slip). It is possible to bypass the security measures provided by decompress and conduct ZIP path traversal through symlinks.

PoC

const decompress = require('decompress');

decompress('slip.tar.gz', 'dist').then(files => { console.log('done!'); });

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