Hashcat

• To identify the type of hash, we could a tool such as hashid or hash-identifier

Example

• Hash f806fc5a2a0d5ba2471600758452799c

hashcat -a 0 -m 0 f806fc5a2a0d5ba2471600758452799c /usr/share/wordlists/rockyou.txt
hashcat (v6.1.1) starting...
f806fc5a2a0d5ba2471600758452799c:rockyou

Session..........: hashcat
Status...........: Cracked
Hash.Name........: MD5
Hash.Target......: f806fc5a2a0d5ba2471600758452799c
Time.Started.....: Mon Oct 11 08:20:50 2021 (0 secs)
Time.Estimated...: Mon Oct 11 08:20:50 2021 (0 secs)
Guess.Base.......: File (/usr/share/wordlists/rockyou.txt)
Guess.Queue......: 1/1 (100.00%)
Speed.#1.........:   114.1 kH/s (0.02ms) @ Accel:1024 Loops:1 Thr:1 Vec:8
Recovered........: 1/1 (100.00%) Digests
Progress.........: 40/40 (100.00%)
Rejected.........: 0/40 (0.00%)
Restore.Point....: 0/40 (0.00%)
Restore.Sub.#1...: Salt:0 Amplifier:0-1 Iteration:0-1
Candidates.#1....: 123456 -> 123123

Started: Mon Oct 11 08:20:49 2021
Stopped: Mon Oct 11 08:20:52 2021

• -a 0 sets the attack mode to a dictionary attack

• -m 0 sets the hash mode for cracking MD5 hashes; for other types, run hashcat -h for a list of supported hashes.

• f806fc5a2a0d5ba2471600758452799c this option could be a single hash like our example or a file that contains a hash or multiple hashes.

• /usr/share/wordlists/rockyou.txt the wordlist/dictionary file for our attack

• We run hashcat with --show option to show the cracked value if the hash has been cracked:

hashcat -a 0 -m 0 F806FC5A2A0D5BA2471600758452799C /usr/share/wordlists/rockyou.txt --show
f806fc5a2a0d5ba2471600758452799c:rockyou

Brute-Force attack

• Brute force a 4 digit pin

hashcat -a 3 ?d?d?d?d --stdout
1234
0234
2234
3234
9234
4234
5234
8234
7234
6234
..
..

• -a 3 sets the attacking mode as a brute-force attack

• ?d?d?d?d the ?d tells hashcat to use a digit. In our case, ?d?d?d?d for four digits starting with 0000 and ending at 9999

• --stdout print the result to the terminal

Example of 4 digit pin hash

hashcat -a 3 -m 0 05A5CF06982BA7892ED2A6D38FE832D6 ?d?d?d?d
05a5cf06982ba7892ed2a6d38fe832d6:2021

Session..........: hashcat
Status...........: Cracked
Hash.Name........: MD5
Hash.Target......: 05a5cf06982ba7892ed2a6d38fe832d6
Time.Started.....: Mon Oct 11 10:54:06 2021 (0 secs)
Time.Estimated...: Mon Oct 11 10:54:06 2021 (0 secs)
Guess.Mask.......: ?d?d?d?d [4]
Guess.Queue......: 1/1 (100.00%)
Speed.#1.........: 16253.6 kH/s (0.10ms) @ Accel:1024 Loops:10 Thr:1 Vec:8
Recovered........: 1/1 (100.00%) Digests
Progress.........: 10000/10000 (100.00%)
Rejected.........: 0/10000 (0.00%)
Restore.Point....: 0/1000 (0.00%)
Restore.Sub.#1...: Salt:0 Amplifier:0-10 Iteration:0-10
Candidates.#1....: 1234 -> 6764

Started: Mon Oct 11 10:54:05 2021
Stopped: Mon Oct 11 10:54:08 2021