Arbitrary File Write via Archive Extraction (Zip Slip)

Affecting code.cloudfoundry.org/archiver package

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Overview

code.cloudfoundry.org/archiver is Utilities for extracting and compressing tgz and zip files..

Affected versions of the package are vulnerable to Arbitrary File Write via Archive Extraction (AKA "Zip Slip").

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 code.cloudfoundry.org/archiver to hash 09b5706aa9367972c09144a450bb4523049ee840.

References

CVSS Score

9.4
high severity
  • Attack Vector
    Network
  • Attack Complexity
    Low
  • Privileges Required
    None
  • User Interaction
    None
  • Scope
    Unchanged
  • Confidentiality
    Low
  • Integrity
    High
  • Availability
    High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:H/E:H/RL:U/RC:C
Credit
M. Hanselmann
CWE
CWE-29
Snyk ID
SNYK-GOLANG-CODECLOUDFOUNDRYORGARCHIVER-50073
Disclosed
27 May, 2018
Published
10 Jun, 2018