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Tag: active directory

Hunting With Active Directory Replication Metadata

With the recent release of BloodHound’s ACL Attack Path Update as well as the work on Active Directory DACL backdooring by @_wald0 and myself (whitepaper here), I started to investigate ACL-based attack paths from a defensive perspective. Sean Metcalf has done some great work concerning Active Directory threat hunting (see his 2017 BSides Charm “Detecting the Elusive: Active Directory Threat Hunting” presentation) and I wanted to show how replication metadata can help in detecting this type of malicious activity. Also, after this post had been drafted, Grégory LUCAND pointed out to me the extensive article (in French) he authored on…

A Pentester’s Guide to Group Scoping

Scopes for Active Directory groups were always a bit murky for me. For anyone with an AD sysadmin background, this topic is probably second nature, but it wasn’t until I read this SS64 entry that everything started to fall into place. I wanted to document some relevant notes on the topic (as I understand it) in case anyone else had the same confusion I did. I’ll also cover how these group scopes interact with the forest global catalog and domain trusts, sprinkling in new PowerView functionality along the way. Active Directory Groups Active Directory groups can have one of two types:…

Command and Control Using Active Directory

‘Exotic’ command and control (C2) channels always interest me. As defenses start to get more sophisticated, standard channels that have been stealthy before (like DNS) may start to lose their efficacy. I’m always on the lookout for non-obvious, one-way (or ideally two-way) communication methods. This post will cover a proof of concept for an internal C2 approach that uses standard Active Directory object properties in a default domain setup. Active Directory Property Sets This dawned on me when reviewing access control list entry information during training prep. In a default domain setup, there is a set of ACLs for user objects that apply to the user itself, defined…