Sub-technique of T1558 Steal or Forge Kerberos Tickets.View on attack.mitre.org
Adversaries may reveal credentials of accounts that have disabled Kerberos preauthentication by Password Cracking Kerberos messages.
Preauthentication offers protection against offline Password Cracking. When enabled, a user requesting access to a resource initiates communication with the Domain Controller (DC) by sending an Authentication Server Request (AS-REQ) message with a timestamp that is encrypted with the hash of their password. If and only if the DC is able to successfully decrypt the timestamp with the hash of the user’s password, it will then send an Authentication Server Response (AS-REP) message that contains the Ticket Granting Ticket (TGT) to the user. Part of the AS-REP message is signed with the user’s password.
For each account found without preauthentication, an adversary may send an AS-REQ message without the encrypted timestamp and receive an AS-REP message with TGT data which may be encrypted with an insecure algorithm such as RC4. The recovered encrypted data may be vulnerable to offline Password Cracking attacks similarly to Kerberoasting and expose plaintext credentials.
An account registered to a domain, with or without special privileges, can be abused to list all domain accounts that have preauthentication disabled by utilizing Windows tools like PowerShell with an LDAP filter. Alternatively, the adversary may send an AS-REQ message for each user. If the DC responds without errors, the account does not require preauthentication and the AS-REP message will already contain the encrypted data.
Cracked hashes may enable Persistence, Privilege Escalation, and Lateral Movement via access to Valid Accounts.
Rules on DetectionCode tagged with T1558.004.
| Rule | Type | Risk | Data source |
|---|---|---|---|
| Disabled Kerberos Pre-Authentication Discovery With Get-ADUser | TTP | NULL | Powershell Script Block Logging 4104 |
| Disabled Kerberos Pre-Authentication Discovery With PowerView | TTP | NULL | Powershell Script Block Logging 4104 |
| Kerberos Pre-Authentication Flag Disabled in UserAccountControl | TTP | NULL | Windows Event Log Security 4738 |
| Kerberos Pre-Authentication Flag Disabled with PowerShell | TTP | NULL | Powershell Script Block Logging 4104 |
| Rubeus Command Line Parameters | TTP | NULL | Sysmon EventID 1, Windows Event Log Security 4688, CrowdStrike ProcessRollup2 |
| Windows Process With NetExec Command Line Parameters | TTP | NULL | Windows Event Log Security 4688, Sysmon EventID 1, CrowdStrike ProcessRollup2 |
None recorded.
None recorded.
Data from MITRE ATT&CK® (Enterprise). ATT&CK® is a registered trademark of The MITRE Corporation.
