Arbitrary File Write via Archive Extraction (Zip Slip)

Affecting decompress-zip package, versions <0.2.2 || >=0.3.0 <0.3.2

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Overview

decompress-zip extracts the contents of the ZIP archive file.

Affected versions of this package are vulnerable to Arbitrary File Write via Archive Extraction (Zip Slip). The package will extract files outside of the scope of the specified target directory because there is no validation that file extraction stays within the defined target path.

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

Remediation

Upgrade decompress-zip to version 0.2.2, 0.3.2 or higher.

References

CVSS Score

9.8
high severity
  • Attack Vector
    Network
  • Attack Complexity
    Low
  • Privileges Required
    None
  • User Interaction
    None
  • Scope
    Unchanged
  • Confidentiality
    High
  • Integrity
    High
  • Availability
    High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Credit
Unknown
CWE
CWE-29
Snyk ID
SNYK-JS-DECOMPRESSZIP-73598
Disclosed
16 Jan, 2019
Published
24 Jan, 2019