Preventing a Domain Admin Breach With ASM’s Inactive Tier Zero Account Detection
Overview
A mid-sized organization experienced a silent but severe security breach stemming from a forgotten Tier Zero service account—a privileged identity originally created years earlier by a third-party service provider. Because the account was inactive and unmonitored, an attacker was able to exploit it to gain full domain admin access. After the incident, Sedara’s Attack Surface Management (ASM) platform was deployed, revealing several more hidden privileged accounts that could have exposed the customer to additional compromise.
Challenge
The customer had no continuous monitoring of privileged or legacy Active Directory accounts. This created three major problems:
- Forgotten privileged accounts remained active long after vendors completed their work.
- Tier Zero identities were not centrally tracked or reviewed.
- Inactive high-privilege accounts were not disabled, audited, or monitored in any meaningful way.
These blind spots created an ideal environment for attackers to escalate privileges without raising alarms.
Incident Summary
An attacker discovered a dormant Tier Zero service account left over from a long-past service engagement.
Because of its elevated permissions and inactivity, it blended into the environment unnoticed.
The attacker used it to:
- Gain full domain admin
- Add permissions to additional accounts
- Expand access deeper into the network
- Maintain persistence for an extended period
The organization had no idea the account was being abused — or that it even still existed.
How ASM Helped
After the breach was contained, Sedara implemented the ASM Active Directory integration.
Within minutes, ASM identified:
- The original compromised Tier Zero account
- Four additional inactive service accounts with elevated permissions
- Multiple misconfigurations that could have enabled further lateral movement
ASM’s Inactive Tier Zero Accounts detection surfaces:
- Dormant privileged identities
- Abandoned service accounts
- Vendor accounts that outlived their need
- Accounts with domain-level permissions no one is watching
This visibility required no complex setup.
Just plug in Active Directory — ASM does the discovery automatically.
Impact
If ASM had been in place prior to the incident, the compromised account would have been flagged immediately, preventing the attacker from using an unknown privileged identity to obtain domain admin access.
- After deployment, ASM enabled the customer to:
- Identify and remediate forgotten Tier Zero accounts
- Eliminate pathways attackers could have reused
- Improve identity hygiene across the environment
- Reduce risk tied to external vendors and legacy configurations
- Establish ongoing visibility into privileged accounts
Key Takeaway
Hidden or inactive Tier Zero accounts are one of the most dangerous vulnerabilities in any environment.
ASM makes them visible instantly, allowing organizations to secure their identity layer before attackers exploit it.