Hashcat

Hashcat is the self-proclaimed world’s fastest CPU-based password recovery tool. It is released as free software (it had a proprietary codebase until 2015). Versions are available for Linux, OS X, and Windows and can come in CPU-based or GPU-based variants. Examples of hashcat supported hashing algorithms are Microsoft LM hashes, MD4, MD5, SHA-family, Unix Crypt formats, MySQL, Cisco PIX.

Hashcat has made its way into the news many times for the optimizations and flaws discovered by its creator, which become exploited in subsequent hashcat releases. (For example, the flaw in 1Password's password manager hashing scheme.)^[1]

Variants

Hashcat used to come in two main variants:

• Hashcat - A CPU-based password recovery tool
• oclHashcat/cudaHashcat - A GPU-accelerated tool (OpenCL or CUDA)

With the release of hashcat v3.00 the GPU and CPU tools were merged into a single tool called hashcat v3.00. hashcat the CPU only version became hashcat-legacy. ^[2]

Many of the algorithms supported by hashcat-legacy can be cracked in a shorter time by using the well-documented GPU acceleration^[3] leveraged in oclHashcat, cudaHashcat and hashcat v3.00(such as MD5, SHA1, and others). However, not all algorithms can be accelerated by leveraging GPUs. Bcrypt is a good example of this. Due to factors such as data-dependent branching, serialization, and memory (to name just a few), oclHashcat/cudaHashcat weren't catchall replacements for hashcat-legacy.

hashcat-legacy is available for Linux, OSX and Windows. oclHashcat/cudaHashcat is only available for Linux and Windows due to improper implementations in OpenCL on OSX.^[4] . hashcat is available for OSX, Windows, and Linux with GPU, CPU and generic OpenCL support which allows for FPGA's and other accelerator cards.

Sample output

$ ./hashcat-cli64.bin examples/A0.M0.hash examples/A0.M0.word
Initializing hashcat v0.47 by atom with 8 threads and 32mb segment-size...

Added hashes from file examples/A0.M0.hash: 102 (1 salts)

NOTE: press enter for status-screen

--- Output Omitted ---

All hashes have been recovered

Input.Mode: Dict (examples/A0.M0.word)
Index.....: 1/1 (segment), 102 (words), 2769 (bytes)
Recovered.: 102/102 hashes, 1/1 salts
Speed/sec.: - plains, - words
Progress..: 102/102 (100.00%)
Running...: --:--:--:--
Estimated.: --:--:--:--

Started: Tue Dec 10 18:07:54 2013
Stopped: Tue Dec 10 18:07:54 2013

Attack types

Hashcat offers multiple attack modes for obtaining effective and complex coverage over a hash's keyspace. These modes are:

• Brute-Force attack
• Combinator attack
• Dictionary attack
• Fingerprint attack
• Hybrid attack
• Mask attack
• Permutation attack
• Rule-based attack
• Table-Lookup attack
• Toggle-Case attack
• PRINCE attack^[5] (in CPU version 0.48 and higher only)

The traditional bruteforce attack is considered outdated, and the Hashcat core team recommends the Mask-Attack as a full replacement.

Competitions

Team Hashcat (the official team of the Hashcat software composed of core Hashcat members) won first place in the KoreLogic "Crack Me If you Can" Competitions at DefCon in 2010, 2012, 2014 and 2015.^[6]

See also

• Password cracking
• Crack (password software)
• Brute-force search
• Brute-force attack
• Computer hacking
• Hacking tool
• Aircrack-ng
• Cain and Abel
• DaveGrohl
• Hash Code cracker
• John the Ripper
• L0phtCrack
• Openwall Project
• Ophcrack
• RainbowCrack

References

External links

• Official website
• source code repositories
• A guide to password cracking with Hashcat
• Measuring Real-World Accuracies and Biases in Modeling Password Guessability
• Confessions of a crypto cluster operator
• Hashcat state of the union
• DEFCON 2010, "Crack Me If you Can": Writeup Team Hashcat
• DEFCON 2011, "Crack Me If you Can": Writeup Team Hashcat
• DEFCON 2014, "Crack Me If you Can": Writeup Team Hashcat
• DEFCON 2015, "Crack Me If you Can": Writeup Team Hashcat
• Goodin, Dan (27 August 2013). "thereisnofatebutwhatwemake - Turbo Charged Cracking Comes to Long Passwords". ars technica.