Arbitrary File Write via Archive Extraction (Zip Slip) Affecting github.com/mholt/archiver/v3/cmd/arc package, versions >=3.0.0 <3.3.2


0.0
medium
  • Attack Complexity

    Low

  • User Interaction

    Required

  • Integrity

    High

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  • snyk-id

    SNYK-GOLANG-GITHUBCOMMHOLTARCHIVERV3CMDARC-1083919

  • published

    16 May 2019

  • disclosed

    13 May 2019

  • credit

    Giulio Comi

How to fix?

Upgrade github.com/mholt/archiver/v3/cmd/arc to version 3.3.2 or higher.

Overview

github.com/mholt/archiver/v3/cmd/arc is a cross-platform, multi-format archive utility and Go library.

Affected versions of this package are vulnerable to Arbitrary File Write via Archive Extraction (Zip Slip) via the Unarchive functions.

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