Use Alternate Authentication Material: Pass the Ticket
Adversaries may "pass the ticket" using stolen Kerberos tickets to move laterally within an environment, bypassing normal system access controls. Pass the ticket (PtT) is a method of authenticating to a system using Kerberos tickets without having access to an account's password. Kerberos authentication can be used as the first step to lateral movement to a remote system.
In this technique, valid Kerberos tickets for Valid Accounts are captured by OS Credential Dumping. A user's service tickets or ticket granting ticket (TGT) may be obtained, depending on the level of access. A service ticket allows for access to a particular resource, whereas a TGT can be used to request service tickets from the Ticket Granting Service (TGS) to access any resource the user has privileges to access.
Silver Ticket can be obtained for services that use Kerberos as an authentication mechanism and are used to generate tickets to access that particular resource and the system that hosts the resource (e.g., SharePoint).
|Active Directory Configuration||
To contain the impact of a previously generated golden ticket, reset the built-in KRBTGT account password twice, which will invalidate any existing golden tickets that have been created with the KRBTGT hash and other Kerberos tickets derived from it.
Ensure that local administrator accounts have complex, unique passwords.
|Privileged Account Management||
Limit domain admin account permissions to domain controllers and limited servers. Delegate other admin functions to separate accounts.
|User Account Management||
Do not allow a user to be a local administrator for multiple systems.
Audit all Kerberos authentication and credential use events and review for discrepancies. Unusual remote authentication events that correlate with other suspicious activity (such as writing and executing binaries) may indicate malicious activity.
Event ID 4769 is generated on the Domain Controller when using a golden ticket after the KRBTGT password has been reset twice, as mentioned in the mitigation section. The status code 0x1F indicates the action has failed due to "Integrity check on decrypted field failed" and indicates misuse by a previously invalidated golden ticket.
- Metcalf, S. (2014, November 22). Mimikatz and Active Directory Kerberos Attacks. Retrieved June 2, 2016.
- Deply, B. (2014, January 13). Pass the ticket. Retrieved June 2, 2016.
- Campbell, C. (2014). The Secret Life of Krbtgt. Retrieved December 4, 2014.
- Sean Metcalf. (2014, November 10). Kerberos & KRBTGT: Active Directory’s Domain Kerberos Service Account. Retrieved January 30, 2020.
- Metcalf, S. (2015, November 13). Unofficial Guide to Mimikatz & Command Reference. Retrieved December 23, 2015.
- Metcalf, S. (2015, August 7). Kerberos Golden Tickets are Now More Golden. Retrieved December 1, 2017.
- Schroeder, W. (2015, September 22). Mimikatz and DCSync and ExtraSids, Oh My. Retrieved December 4, 2017.
- The Australian Cyber Security Centre (ACSC), the Canadian Centre for Cyber Security (CCCS), the New Zealand National Cyber Security Centre (NZ NCSC), CERT New Zealand, the UK National Cyber Security Centre (UK NCSC) and the US National Cybersecurity and Communications Integration Center (NCCIC). (2018, October 11). Joint report on publicly available hacking tools. Retrieved March 11, 2019.
- Nicolas Verdier. (n.d.). Retrieved January 29, 2018.
- Symantec Security Response. (2015, July 13). “Forkmeiamfamous”: Seaduke, latest weapon in the Duke armory. Retrieved July 22, 2015.
- Dunwoody, M. and Carr, N.. (2016, September 27). No Easy Breach DerbyCon 2016. Retrieved October 4, 2016.
- Counter Threat Unit Research Team. (2017, October 12). BRONZE BUTLER Targets Japanese Enterprises. Retrieved January 4, 2018.
- Dahan, A. (2017). Operation Cobalt Kitty. Retrieved December 27, 2018.
- Abolins, D., Boldea, C., Socha, K., Soria-Machado, M. (2016, April 26). Kerberos Golden Ticket Protection. Retrieved July 13, 2017.