How to identify and crack an MD4 hash

MD4 is an raw / unsalted hash type. It is fast and typically unsalted, which makes weak passwords recoverable quickly on consumer GPU hardware. This page shows how to recognise it and the exact commands to attack it.

All identification runs locally in WebAssembly. The commands below write the hash to a local file on your machine — nothing is sent to this site.

Identifying the hash

The hash identifier on the home page detects MD4 entirely in your browser — your hash is never uploaded. A typical example looks like this:

94e3cb0fa9aa72a61ebb08a3e15d9a83

Cracking MD4 with hashcat

Save the hash to a file and run hashcat in mode -m 900. Start with a wordlist such as rockyou.txt:

echo '94e3cb0fa9aa72a61ebb08a3e15d9a83' > hash.txt && hashcat -m 900 hash.txt /usr/share/wordlists/rockyou.txt

Add a rule set to mutate dictionary words (capitalisation, leetspeak, appended digits) and dramatically widen coverage:

echo '94e3cb0fa9aa72a61ebb08a3e15d9a83' > hash.txt && hashcat -m 900 hash.txt /usr/share/wordlists/rockyou.txt -r /usr/share/hashcat/rules/best64.rule

Cracking MD4 with John the Ripper

John the Ripper can attack the same hash with the raw-md4 format:

echo '94e3cb0fa9aa72a61ebb08a3e15d9a83' > hash.txt && john --format=raw-md4 --wordlist=/usr/share/wordlists/rockyou.txt hash.txt