PowerArchiver: Uses insecure legacy PKZIP encryption when AES is selected (CVE-2014-2319)

References

http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-2319
http://int21.de/cve/CVE-2014-2319-powerarchiver.html
http://www.powerarchiver.com/2014/03/12/powerarchiver-2013-14-02-05-released/

Background

ftp://utopia.hacktic.nl/pub/crypto/cracking/pkzip.ps.gz

Description

The compression tool PowerArchiver version 14.02.03 creates files with an insecure encryption method even if the user selects a (secure) AES encryption in the GUI.

If a user clicks on the "Encrypt Files" and selects "AES 256-bit" for encryption, the outcoming file will not be AES-encrypted. It will instead use the legacy PKZIP encryption, which uses a broken encryption algorithm.

Note that there are different ways in PowerArchiver to create an encrypted ZIP file, the issue only appears when using the "Encrypt Files"-Button.

The PKZIP encryption has been broken by Biham/Kocher in 1994.

The vendor ConeXware has released version 14.02.05 which fixes the issue. It also disables completely support for creating archives with the broken legacy ZIP encryption.

Disclosure Timeline

2014-03-10: Issue found, vendor contacted
2014-03-10: Vendor replies, confirms issue
2014-03-12: Vendor publishes fixed version

Vulnerability found by Hanno Böck.

CC0