How to identify and crack a Kerberos 5 etype 17/18 (TGS, AES) hash

Kerberos 5 etype 17/18 (TGS, AES) is a network authentication 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 Kerberos 5 etype 17/18 (TGS, AES) entirely in your browser — your hash is never uploaded. A typical example looks like this:

$krb5tgs$18$user$realm$...

Cracking Kerberos 5 etype 17/18 (TGS, AES) with hashcat

Save the hash to a file and run hashcat in mode -m 19600. Start with a wordlist such as rockyou.txt:

echo '$krb5tgs$18$user$realm$...' > hash.txt && hashcat -m 19600 hash.txt /usr/share/wordlists/rockyou.txt

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

echo '$krb5tgs$18$user$realm$...' > hash.txt && hashcat -m 19600 hash.txt /usr/share/wordlists/rockyou.txt -r /usr/share/hashcat/rules/best64.rule

Cracking Kerberos 5 etype 17/18 (TGS, AES) with John the Ripper

John the Ripper can attack the same hash with the krb5tgs-aes format:

echo '$krb5tgs$18$user$realm$...' > hash.txt && john --format=krb5tgs-aes --wordlist=/usr/share/wordlists/rockyou.txt hash.txt