Arbitrary File Write via Archive Extraction (Zip Slip) Affecting org.codehaus.plexus:plexus-archiver package, versions [,3.6.0)

org.codehaus.plexus:plexus-archiver is a Collection of Plexus components to create archives or extract files out of an archive to a directory with a unified Archiver/UnArchiver API whatever the archive format is.

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

• https://github.com/codehaus-plexus/plexus-archiver/commit/f8f4233508193b70df33759ae9dc6154d69c2ea8
• https://github.com/codehaus-plexus/plexus-archiver/pull/87
• https://github.com/snyk/zip-slip-vulnerability
• https://security.snyk.io/research/zip-slip-vulnerability