Hashcat is a

password recovery In cryptanalysis and computer security, password cracking is the process of recovering passwords from data that has been stored in or transmitted by a computer system in scrambled form. A common approach (brute-force attack) is to repeatedly tr ...

tool. It had a proprietary code base until 2015, but was then released as open source software. Versions are available for Linux, OS X, and Windows. Examples of hashcat-supported hashing algorithms are

LM hash LAN Manager is a discontinued network operating system (NOS) available from multiple vendors and developed by Microsoft in cooperation with 3Com Corporation. It was designed to succeed 3Com's 3+Share network server software which ran atop a he ...

es,

MD4 The MD4 Message-Digest Algorithm is a cryptographic hash function developed by Ronald Rivest in 1990. The digest length is 128 bits. The algorithm has influenced later designs, such as the MD5, SHA-1 and RIPEMD algorithms. The initialism "MD" s ...

, MD5, SHA-family and Unix Crypt formats as well as algorithms used in

MySQL MySQL () is an open-source relational database management system (RDBMS). Its name is a combination of "My", the name of co-founder Michael Widenius's daughter My, and "SQL", the acronym for Structured Query Language. A relational database o ...

and

Cisco PIX Cisco PIX (Private Internet eXchange) was a popular IP firewall and network address translation (NAT) appliance. It was one of the first products in this market segment. In 2005, Cisco introduced the neweCisco Adaptive Security Appliance( Cisc ...

. Hashcat has been publicly noticed because of its optimizations; partly based on flaws in other software discovered by the creator of hashcat. An example was a flaw in 1Password's password manager hashing scheme. It has also been compared to similar software in a Usenix publication and been described on

Ars technica ''Ars Technica'' is a website covering news and opinions in technology, science, politics, and society, created by Ken Fisher and Jon Stokes in 1998. It publishes news, reviews, and guides on issues such as computer hardware and software, sci ...

Variants

Previously, two variants of hashcat existed: * hashcat - CPU-based password recovery tool * oclHashcat/cudaHashcat - 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. The CPU-only version became hashcat-legacy. Both CPU and GPU now require

OpenCL OpenCL (Open Computing Language) is a framework for writing programs that execute across heterogeneous platforms consisting of central processing units (CPUs), graphics processing units (GPUs), digital signal processors (DSPs), field-progra ...

. Many of the algorithms supported by hashcat-legacy (such as MD5, SHA1, and others) can be cracked in a shorter time with the GPU-based hashcat. However, not all algorithms can be accelerated by GPUs.

Bcrypt bcrypt is a password-hashing function designed by Niels Provos and David Mazières, based on the Blowfish cipher and presented at USENIX in 1999. Besides incorporating a salt to protect against rainbow table attacks, bcrypt is an adaptive fu ...

is an example of this. Due to factors such as data-dependent branching, serialization, and memory (and more), oclHashcat/cudaHashcat weren't catchall replacements for hashcat-legacy. hashcat-legacy is available for Linux, OSX and Windows. hashcat is available for macOS, Windows, and Linux with GPU, CPU and generic OpenCL support which allows for FPGAs and other accelerator cards.

Sample output

$ hashcat -d 2 -a 0 -m 400 -O -w 4 example400.hash example.dict hashcat (v5.1.0) starting... OpenCL Platform #1: Intel(R) Corporation

* Device #1: Intel(R) Core(TM) i5-2500K CPU @ 3.30GHz, skipped. OpenCL Platform #2: NVIDIA Corporation

* Device #2: GeForce GTX 970, 1010/4041 MB allocatable, 13MCU * Device #3: GeForce GTX 750 Ti, skipped. Hashes: 1 digests; 1 unique digests, 1 unique salts Bitmaps: 16 bits, 65536 entries, 0x0000ffff mask, 262144 bytes, 5/13 rotates Rules: 1 Applicable optimizers: * Optimized-Kernel * Zero-Byte * Single-Hash * Single-Salt Minimum password length supported by kernel: 0 Maximum password length supported by kernel: 55 Watchdog: Temperature abort trigger set to 90c Dictionary cache hit: * Filename..: example.dict * Passwords.: 128416 * Bytes.....: 1069601 * Keyspace..: 128416 The wordlist or mask that you are using is too small. This means that hashcat cannot use the full parallel power of your device(s). Unless you supply more work, your cracking speed will drop. For tips on supplying more work, see: https://hashcat.net/faq/morework Approaching final keyspace - workload adjusted. $H$9y5boZ2wsUlgl2tI6b5PrRoADzYfXD1:hash234 Session..........: hashcat Status...........: Cracked Hash.Type........: phpass, WordPress (MD5), phpBB3 (MD5), Joomla (MD5) Hash.Target......: $H$9y5boZ2wsUlgl2tI6b5PrRoADzYfXD1 Time.Started.....: Thu Apr 25 05:10:35 2019 (0 secs) Time.Estimated...: Thu Apr 25 05:10:35 2019 (0 secs) Guess.Base.......: File (example.dict) Guess.Queue......: 1/1 (100.00%) Speed.#2.........: 2654.9 kH/s (22.24ms) @ Accel:128 Loops:1024 Thr:1024 Vec:1 Recovered........: 1/1 (100.00%) Digests, 1/1 (100.00%) Salts Progress.........: 128416/128416 (100.00%) Rejected.........: 0/128416 (0.00%) Restore.Point....: 0/128416 (0.00%) Restore.Sub.#2...: Salt:0 Amplifier:0-1 Iteration:1024-2048 Candidates.#2....: 0 -> zzzzzzzzzzz Hardware.Mon.#2..: Temp: 44c Fan: 40% Util: 50% Core:1265MHz Mem:3004MHz Bus:8 Started: Thu Apr 25 05:10:32 2019 Stopped: Thu Apr 25 05:10:37 2019

Attack types

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

Brute-force attack In cryptography, a brute-force attack consists of an attacker submitting many passwords or passphrases with the hope of eventually guessing correctly. The attacker systematically checks all possible passwords and passphrases until the correc ...

* Combinator attack *

Dictionary attack In cryptanalysis and computer security, a dictionary attack is an attack using a restricted subset of a keyspace to defeat a cipher or authentication mechanism by trying to determine its decryption key or passphrase, sometimes trying thousands o ...

* Fingerprint attack * Hybrid attack * Mask attack * Permutation attack * Rule-based attack * Table-Lookup attack (CPU only) * Toggle-Case attack * PRINCE attack (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 The defense readiness condition (DEFCON) is an alert state used by the United States Armed Forces. (DEFCON is not mentioned in the 2010 and newer document) The DEFCON system was developed by the Joint Chiefs of Staff (JCS) and unified and spe ...

in 2010, 2012, 2014, 2015, and 2018, and at

DerbyCon DerbyCon was a computer security conference based in Louisville, Kentucky. The first DerbyCon took place in 2011 and was founded by Martin Bos, Dave Kennedy, Alex Kah and Adrian Crenshaw. The conference has been held at the Hyatt Regency Louisvil ...

in 2017.

References

External links

*
A guide to password cracking with Hashcat

Talk: Confessions of a crypto cluster operator
based on oclHashcat at

Derbycon DerbyCon was a computer security conference based in Louisville, Kentucky. The first DerbyCon took place in 2011 and was founded by Martin Bos, Dave Kennedy, Alex Kah and Adrian Crenshaw. The conference has been held at the Hyatt Regency Louisvil ...