Abstract

User rights and privileges are a part of the access control model in Active Directory. Applicable only at the local computer level, a user generally has different rights (through access tokens) on different machines in a domain. Another part of the access control model is security descriptors (ACLs) that protects a securable object. At the domain level, ACL abuse is well known and adversaries have used it for persistence. For user rights, the abuse is mostly with the help of groups (memberships, SID History etc.) or misconfigured delegated rights.

A lesser-known area of abuse and offensive research is a combination of minimal Rights and ACE (hence the term RACE). Often overlooked in audits and assessments, using minimal rights along with favourable ACEs provides a very interesting technique of persistence and on-demand privilege escalation on a Windows machine with much desired stealth.

This talk covers interesting domain privilege escalation, persistence and backdoor techniques with the help of ACLs, minimal user rights and combinations of both. We will discuss how these techniques can be applied using open source tools and scripts. The talk also covers how to detect and mitigate such attacks. The talk will be full of live demonstrations.