Microsoft September 2026 Patch Tuesday fixes 966 flaws, 2 zero-days
Microsoft's September 2026 Patch Tuesday fixes a record 966 flaws, including two Windows zero-days actively exploited to gain SYSTEM privileges.
Microsoft's September 2026 Patch Tuesday addresses a record 966 vulnerabilities, including 105 rated Critical, 81 of them remote code execution bugs. Two zero-days were actively exploited: a Windows Update Stack link-following flaw and a Windows ALPC heap-based buffer overflow, both allowing local elevation to SYSTEM privileges. The ALPC flaw was reported by Volexity and Proofpoint researchers, while the Update Stack flaw was credited to Romain Deperne and the Microsoft Threat Intelligence Centre. Microsoft shared no details on how the flaws were exploited in attacks.
CISA Shares 17 Techniques Used by Hackers to Compromise Active Directory
CISA and five international agencies publish joint guidance detailing 17 techniques attackers use to compromise Microsoft Active Directory environments.
CISA, NSA, and the Australian Signals Directorate's ACSC, with contributions from Canadian, UK, and New Zealand cyber centers, released technical guidance on 17 Active Directory attack techniques. It covers AD Domain Services, AD Certificate Services, and AD Federation Services, including Kerberoasting, DCSync, Golden Ticket, Golden SAML, Skeleton Key, and Shadow Credentials. The guidance recommends treating domain controllers, CAs, AD FS servers, and Entra Connect systems as Tier 0 assets with phishing-resistant MFA, Kerberos pre-authentication enforcement, and disabling NTLM/SMBv1.
Hackers Pose as Domain Controllers to Steal Active Directory Password Hashes
Attackers abuse Active Directory replication (DCSync) via the DRSUAPI protocol to steal password hashes and forge Golden Tickets for persistent domain compromise.
Security reporting citing Trellix details how threat actors impersonate domain controllers to request replication data and obtain NTLM password hashes without dumping LSASS on the domain controller. With Domain Admin or replication rights, attackers can steal the KRBTGT hash and forge long-lived Golden Tickets that survive password resets. Defenders should monitor DRSUAPI requests from non-DC systems, restrict replication permissions, and enforce MFA and tiered administrative access.