Who is accountable when a compromised firewall account is used to create rogue systems in Active Directory?

Why This Matters for Security Teams

A compromised firewall account that can create rogue systems in active directory is not just a perimeter issue. It is an identity control failure across two administrative planes: the device that was trusted to guard the edge and the directory that was trusted to define access. NHI Management Group’s Ultimate Guide to NHIs — Why NHI Security Matters Now highlights that 97% of NHIs carry excessive privileges, which is exactly why a single over-entitled account can become a directory foothold.

The accountability question matters because responders often split ownership after the fact: network teams treat the firewall as a security appliance, while identity teams treat AD as a separate domain. That separation breaks down when a trusted device can authenticate into directory services and provision new objects. NIST control guidance in NIST SP 800-53 Rev. 5 Security and Privacy Controls makes clear that access control, audit logging, and system integrity are shared responsibilities, not isolated silos. In practice, many security teams encounter the blast radius only after rogue systems have already been joined to the domain and used for lateral movement.

How It Works in Practice

Accountability should follow control ownership, but incident response must treat the event as a joint compromise. The firewall team owns the privileged device account, its patch state, local admin protections, log forwarding, and any exposed management interfaces. The identity team owns directory change monitoring, computer account creation detection, privileged group membership review, and validation that joins originated from approved automation. If the firewall account is also used for orchestration, then the workflow itself must be reviewed as a privileged identity path.

Practically, this means responders should ask four questions at once:

• Was the firewall account intended to create or register systems in AD?
• Were the credentials stored as a long-lived secret or protected as a short-lived workload identity?
• Did the directory record show unusual machine joins, delegation changes, or new service principals?
• Did the edge device send logs to a place the identity team can actually review?

This is the same governance pattern NHIMG describes in the 52 NHI Breaches Analysis: once a non-human identity is overprivileged and poorly observed, it can be used to create persistent access that looks legitimate to both the network stack and the directory. Current guidance suggests mapping these accounts to named business owners, then enforcing separate approval for device administration and directory object creation. These controls tend to break down in environments where firewall management is delegated to automation teams but AD change control remains invisible to them, because nobody is watching the full attack path end to end.

Common Variations and Edge Cases

Tighter account control often increases operational overhead, requiring organisations to balance response speed against change friction. That tradeoff is especially visible when firewall accounts are used by orchestration platforms, MSPs, or emergency break-glass processes. Best practice is evolving, but there is no universal standard for whether the firewall team, the identity team, or a shared service owner should be the primary accountable party in every case. The decision should follow who provisions the credential, who approves the privilege, and who can revoke it fastest.

Edge cases usually involve delegated administration, temporary migrations, or vendor-managed appliances. In those scenarios, the account may be technically owned by infrastructure while the impact lands in identity. The safest model is to treat rogue AD system creation as an identity incident with network-origin evidence. That means preserving the firewall audit trail, checking for abuse of directory rights, and resetting any shared secrets or certificates tied to the device. If the environment lacks strong separation between administrative workstations, device management networks, and directory administration paths, attribution becomes messy and response responsibility can be disputed even when the compromise path is obvious.

NHIMG’s Cisco Active Directory credentials breach is a reminder that edge-device compromise can cascade into directory compromise when privileged access is not segmented and monitored carefully.

Related resources from NHI Mgmt Group

• Who is accountable for verifying that an Active Directory certificate security fix is actually enforced after patching?
• How should security teams govern Active Directory service accounts?
• Who is accountable when a compromised business account is used for ad fraud or SSO pivoting?
• Who is accountable when a compromised machine identity is used to reach sensitive systems?