# 88 - Kerberos ## User Enumeration Enumerate valid Domain Users via Kerberos from a wholly unauthenticated perspective. It utilises the different responses returned by the service to identify users that exist within the target domain. ### Metasploit Use `msf > use auxiliary/gather/kerberos_enumusers` Example ``` msf auxiliary(kerberos_enumusers) > set DOMAIN MYDOMAIN DOMAIN => MYDOMAIN msf auxiliary(kerberos_enumusers) > set RHOST 192.168.5.1 RHOST => 192.168.5.1 msf auxiliary(kerberos_enumusers) > set USER_FILE /job/users.txt USER_FILE => /job/users.txt msf auxiliary(kerberos_enumusers) > run [*] Validating options... [*] Using domain: MYDOMAIN... [*] 192.168.5.1:88 - Testing User: "bob"... [*] 192.168.5.1:88 - KDC_ERR_PREAUTH_REQUIRED - Additional pre-authentication required [+] 192.168.5.1:88 - User: "bob" is present [*] 192.168.5.1:88 - Testing User: "alice"... [*] 192.168.5.1:88 - KDC_ERR_PREAUTH_REQUIRED - Additional pre-authentication required [+] 192.168.5.1:88 - User: "alice" is present [*] 192.168.5.1:88 - Testing User: "matt"... [*] 192.168.5.1:88 - KDC_ERR_PREAUTH_REQUIRED - Additional pre-authentication required [+] 192.168.5.1:88 - User: "matt" is present [*] 192.168.5.1:88 - Testing User: "guest"... [*] 192.168.5.1:88 - KDC_ERR_CLIENT_REVOKED - Clients credentials have been revoked [-] 192.168.5.1:88 - User: "guest" account disabled or locked out [*] 192.168.5.1:88 - Testing User: "admint"... [*] 192.168.5.1:88 - KDC_ERR_C_PRINCIPAL_UNKNOWN - Client not found in Kerberos database [*] 192.168.5.1:88 - User: "admint" does not exist [*] 192.168.5.1:88 - Testing User: "admin"... [*] 192.168.5.1:88 - KDC_ERR_C_PRINCIPAL_UNKNOWN - Client not found in Kerberos database [*] 192.168.5.1:88 - User: "admin" does not exist [*] 192.168.5.1:88 - Testing User: "administrator"... [*] 192.168.5.1:88 - KDC_ERR_C_PRINCIPAL_UNKNOWN - Client not found in Kerberos database [*] 192.168.5.1:88 - User: "administrator" does not exist [*] Auxiliary module execution completed msf auxiliary(kerberos_enumusers) > ``` ### Nmap ``` Nmap –p 88 –script-args krb5-enum-users.realm=’[domain]’,userdb=[user list] [DC IP] ``` ### Kerbrure A tool to quickly bruteforce and enumerate valid Active Directory accounts through Kerberos Pre-Authentication Link: ``` root@kali# kerbrute userenum -d EGOTISTICAL-BANK.LOCAL /usr/share/seclists/Usernames/xato-net-10-million-usernames.txt --dc 10.10.10.175 ``` --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://infra.newerasec.com/infrastructure-testing/enumeration/services-ports/88-kerberos.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.