The Breach That Never Happened — Issue #002
The 15-Minute Domain Takeover
Finding: Active Directory DCSync Attack
Severity: Critical
Time to Exploit: 15 minutes
Cost if Breached: $2–5 million
What Happened
During a routine penetration test, we discovered a critical flaw in a company’s Active Directory. With one compromised user account, we were able to extract every password in the organization, including administrator credentials, in under 15 minutes.
No password cracking. No zero-day exploits. Just a misconfigured permission that allowed us to impersonate a domain controller.
The issue was reported and corrected. No breach occurred.
T.L.D.R.
Active Directory allows domain controllers to share password data with each other, similar to bank branches syncing customer records. Occasionally, user accounts are mistakenly granted permission to request this data.
An attacker who compromises such an account can effectively say:
“I’m a domain controller. Send me all password data.”
And the system complies.
The Impact
With DCSync access, an attacker could:
• Access any user account, including executives and administrators
• Access company email and file systems
• Deploy ransomware across the environment
• Create persistent backdoor access
• Remain undetected for extended periods
Real-world precedent: This technique was used in major incidents such as the NotPetya attack ($10 billion in damages) and the SolarWinds breach.
How To Fix It
• Audit Active Directory permissions to identify over-privileged accounts
• Remove replication rights from non-domain controller accounts
• Enable monitoring for DCSync attempts
• Deploy identity monitoring and alerting controls
These measures significantly reduce the risk of domain compromise.
Key Takeaways
If you’re a business leader:
This issue is common, preventable, and far less costly to address proactively than to recover from after an incident.
If you’re technical:
Audit your Active Directory permissions and identify accounts with “Replicating Directory Changes” rights.
Bottom line:
Penetration testing identifies these weaknesses before they are exploited, allowing organizations to correct them before damage occurs.
What You Can Do
[ ] Audit Active Directory permissions (approximately 5 minutes)
[ ] Enable Directory Service Access auditing (approximately 10 minutes)
[ ] Conduct regular security assessments to identify vulnerabilities early
This vulnerability was discovered during a real penetration test and remediated before publication.
About “The Breach That Never Happened”
Monthly insights drawn from real penetration testing engagements, highlighting vulnerabilities that were identified and resolved before incidents occurred.
Discovered by Penti’s Agent and Penetration Testing Team.
#CyberSecurity #PenetrationTesting #ActiveDirectory #PreventedBreach #DCSync