ACTIVE DIRECTORY UNDER SIEGE: WHY CRITICAL INFRASTRUCTURE NEEDS STRONGER SECURITY

Summary from the TLDR InfoSec newsletter

Active Directory remains the authentication backbone for 90% of Fortune 1000 companies, with attackers exploiting golden ticket attacks, DCSync privilege escalation, Kerberoasting, and compromised credentials (involved in 88% of breaches per Verizon DBIR) to gain network-wide control, as demonstrated by the 2024 Change Healthcare breach, where MFA absence enabled full AD compromise. Critical vulnerabilities include weak passwords, service accounts with excessive permissions and non-expiring credentials, cached admin credentials in memory, legacy NTLM protocol exploitation, and hybrid environment complexity, creating visibility gaps between on-premises and cloud security teams. Implement layered defenses, including continuous credential monitoring against breach databases (blocking 4B+ compromised passwords), privileged access management with just-in-time elevation, zero-trust conditional access with MFA for all privileged accounts, continuous AD change monitoring for suspicious patterns, and aggressive patching of domain controllers within days of security updates.