The ASREPRoast attack looks for **users without Kerberos pre-authentication required attribute (**[_**DONT\_REQ\_PREAUTH**_](https://support.microsoft.com/en-us/help/305144/how-to-use-the-useraccountcontrol-flags-to-manipulate-user-account-pro)_**)**_.
That means that anyone can send an AS\_REQ request to the DC 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.
Furthermore, **no domain account is needed to perform this attack**, only connection to the DC. However, **with a domain account**, a LDAP query can be used to **retrieve users without Kerberos pre-authentication** in the domain. **Otherwise usernames have to be guessed**.
[**More information about AS-RRP Roasting in ired.team**](https://ired.team/offensive-security-experiments/active-directory-kerberos-abuse/as-rep-roasting-using-rubeus-and-hashcat)