A vulnerability has been discovered in UnZip, which potentially can be exploited by malicious people to compromise a user's system.

Last year a directory traversal vulnerability was discovered in UnZip. An updated version (5.50) was issued to address the vulnerability but apparently the vulnerability was not fixed properly in this version.

UnZip filters "../" in front of filenames in archives. However, a malicious person can still traverse directories on a system by including an encoded value between the two dots (eg. ". \003 ./[filename]"). UnZip will ignore the encoded value and then extract the file to "../[filename]".

This can be exploited to overwrite arbitrary files outside the directory, where the files are extracted to, if a user is tricked into extracting a malicious archive using UnZip.

Solution
The vulnerability has been fixed in UnZip 5.51.

Provided and/or discovered by
jelmer

Changelog
Further details available to Secunia VIM customers

Deep Links
Links available to Secunia VIM customers