Retrospect Backup Client is a client to a network-based backup utility. This client stores passwords in a hashed format that is weak and susceptible to collision, allowing an attacker to generate a password hash collision and gain access to the target's backup files.
CWE-916: Use of Password Hash With Insufficient Computational Effort - CVE-2015-2864
Retrospect Backup clients prior to 10.0.2 on Windows and Linux and 12.0.2 on Mac contain an error in the password hash generating algorithm. The password is not fully utilized when generating a hash, allowing the possibility of a weak hash with a higher probability of collision with other passwords. Attackers with network access to a machine running the Retrospect client may be able to generate brute-force passwords that are guaranteed to collide with the hashed password with a maximum of 128 tries. This attack was demonstrated by security researchers Josep Pi Rodriguez and Pedro Guillen Nunez.
An unauthenticated attacker on the network may be able to brute force a correct password by guessing a string that produces the same hash, granting access to backup data as the victim user.
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Thanks to Josep Pi Rodriguez and Pedro Guillen Nunez for working with the CERT/CC and the vendor, and thanks to Retrospect for quickly addressing the issue.
This document was written by Garret Wassermann.
|Date First Published:||2015-06-15|
|Date Last Updated:||2015-06-15 21:42 UTC|