August updates trigger 0xc0000409 errors on Windows Server 2016
Microsoft says the August 2026 security update causes recurring CompatTelRunner.exe 0xc0000409 crashes on Windows Server 2016 with Compatibility Appraiser enabled; no functional impact.
Microsoft confirmed a known issue in which the August 2026 Windows security update generates recurring Application Error events (Event ID 1000, exception code 0xc0000409) in CompatTelRunner.exe on Windows Server 2016. The issue affects physical and virtual machines, including VMware and Azure environments, and per Microsoft does not affect device functionality. A permanent fix is planned for a future update, and the event log entries can be dismissed temporarily.
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.
CISA Warns Hackers Exploit 17 Active Directory Techniques to Gain Control of Enterprise Networks
CISA and Five Eyes agencies issued joint guidance detailing 17 Active Directory attack techniques like Kerberoasting and DCSync, with hardening and detection advice.
CISA, the NSA, and cyber agencies from Australia, Canada, the UK, and New Zealand released joint guidance on September 15 covering 17 techniques attackers use to compromise Active Directory, including AD CS, Certificate Services, and Federation Services attacks. Named techniques include Kerberoasting, AS-REP roasting, password spraying, DCSync, NTDS.dit dumping, Golden and Silver Tickets, Golden SAML, and Skeleton Key. Recommendations include minimizing SPN accounts, enforcing AES encryption, disabling NTLM, account lockout thresholds of five attempts, phishing-resistant MFA, and Tier 0 prioritization. The guide also lists Windows event IDs 4769, 4768, 4625, 4771, and 2889 for detecting Kerberoasting and password spraying on domain controllers.
Microsoft: Windows Server 2025 changes causing app crashes
Microsoft warns Windows Server 2025 memory-management changes crash AWE apps, including SQL Server with Lock Pages in Memory; disable LPIM as workaround.
Microsoft confirmed a known issue where Windows Server 2025 memory-management changes cause access violations, memory corruption, or unexpected termination in applications using Address Windowing Extensions (AWE). SQL Server running with the Lock Pages in Memory (LPIM) policy is affected, with symptoms including 0xC0000005 access violations, DBCC CHECKDB failures, crash dumps, and services stopping or restarting unexpectedly. Microsoft's temporary workaround is to disable the LPIM policy for the SQL Server service account or disable AWE in other affected apps, with a permanent fix promised in a future Windows update.