Arbitrary File Write via Archive Extraction (Zip Slip) Affecting w-zip package, versions <1.0.12


Severity

Recommended
0.0
critical
0
10

CVSS assessment made by Snyk's Security Team. Learn more

Threat Intelligence

Exploit Maturity
Proof of concept
EPSS
0.34% (73rd percentile)

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  • Snyk IDSNYK-JS-WZIP-2389220
  • published1 Feb 2022
  • disclosed1 Feb 2022
  • creditsheldor2021

Introduced: 1 Feb 2022

CVE-2022-0401  (opens in a new tab)
CWE-29  (opens in a new tab)

How to fix?

Upgrade w-zip to version 1.0.12 or higher.

Overview

w-zip is an A compression tool with zip and 7z.

Affected versions of this package are vulnerable to Arbitrary File Write via Archive Extraction (Zip Slip) via the mzip.unZip() function, which does not check relative path named files (i.e. ..\..\..\..\..\tmp), allowing for files to be extracted to a place outside of the target directroy.

PoC

var wz = require('w-zip');

let fpUnzip = './testData/outputZip'
let fpUnzipExtract = fpUnzip + '/extract'
let fpZip1 = fpUnzip + '/zipslip.zip'

async function checkzipslip() {

    //unzip
    console.log('unzip1 before')
    console.log('unzip1', await wz.mZip.unzip(fpZip1, fpUnzipExtract + '/zipslip'))
    console.log('unzip1 after')

}
checkzipslip()
    .catch((err) => {
        console.log(err)
    })

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

References

CVSS Scores

version 3.1