Abusing S4U2Self for Active Directory Pivoting
Summary
This article details a method for leveraging the Kerberos S4U2Self proxy to achieve local privilege escalation within Active Directory. By utilizing a valid machine hash, attackers can reopen and expand pivoting paths, such as SEImpersonate.
IFF Assessment
The article describes a technique that can be used by attackers to gain elevated privileges and move laterally within an Active Directory environment.
Severity
This score reflects a high severity for privilege escalation and lateral movement within a critical enterprise infrastructure component like Active Directory, assuming an attacker has already gained some level of access (e.g., a machine hash). The impact on confidentiality, integrity, and availability could be significant.
Defender Context
Defenders should be aware of this S4U2Self abuse technique as it presents a sophisticated pivoting method within Active Directory environments. Monitoring for unusual Kerberos requests and unusual lateral movement patterns after initial compromise is crucial.