Arbitrary File Write via Archive Extraction (Zip Slip) Affecting dnn.platform Open this link in a new tab package, versions [0,]


0.0
medium
  • Attack Complexity

    Low

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications
  • snyk-id

    SNYK-DOTNET-DNNPLATFORM-551997

  • published

    24 Feb 2020

  • disclosed

    24 Feb 2020

  • credit

    Unknown

How to fix?

A fix was pushed into the master branch but not yet published.

Overview

Dnn.Platform is a Open Source Web Application Framework.

Affected versions of this package are vulnerable to Arbitrary File Write via Archive Extraction (Zip Slip). The zip file extraction function of DNN file upload feature allows an attacker to replace any files with following extension on system - jpg, jpeg, jpe, gif, bmp, png, svg, ttf, eot, woff, doc, docx, xls, xlsx, ppt, pptx, pdf, txt, xml, xsl, xsd, css, zip, rar, template, htmtemplate, ico, avi, mpg, mpeg, mp3, wmv, mov, wav, mp4, webm, ogv.

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