Arbitrary File Write via Archive Extraction (Zip Slip) Affecting langchain package, versions <0.2.19


Severity

Recommended
0.0
medium
0
10

CVSS assessment made by Snyk's Security Team

    Threat Intelligence

    Exploit Maturity
    Proof of concept
    EPSS
    0.13% (49th percentile)

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  • Snyk ID SNYK-JS-LANGCHAIN-8310293
  • published 30 Oct 2024
  • disclosed 29 Oct 2024
  • credit dastaj

How to fix?

Upgrade langchain to version 0.2.19 or higher.

Overview

langchain is a Typescript bindings for langchain

Affected versions of this package are vulnerable to Arbitrary File Write via Archive Extraction (Zip Slip) in the getFullPath method, which allows an attacker to save files anywhere in the filesystem through the setFileContent function, overwrite and read existing text files through the getParsedFile function, and delete files through the mdelete function.

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 Scores

version 4.0
version 3.1
Expand this section

Snyk

Recommended
6.9 medium
  • Attack Vector (AV)
    Network
  • Attack Complexity (AC)
    Low
  • Attack Requirements (AT)
    None
  • Privileges Required (PR)
    None
  • User Interaction (UI)
    None
  • Confidentiality (VC)
    Low
  • Integrity (VI)
    Low
  • Availability (VA)
    None
  • Confidentiality (SC)
    None
  • Integrity (SI)
    None
  • Availability (SA)
    None