event logs Archives

Winsage

May 21, 2026

Microsoft Defender Zero-Day Vulnerabilities RedSun and UnDefend Actively Exploited on Windows 10, 11, and Server (April 2026 CVE Analysis)

In April 2026, two zero-day vulnerabilities, RedSun and UnDefend, were discovered in Microsoft Defender, affecting Windows 10, Windows 11, and Windows Server platforms. These vulnerabilities allow attackers to escalate privileges to SYSTEM and bypass Defender’s protections. RedSun exploits a flaw in Defender's remediation process, enabling low-privileged users to overwrite critical system files. UnDefend allows attackers to disrupt Defender’s updates, keeping it outdated and ineffective. Both vulnerabilities are actively being exploited, with attackers leveraging them to gain persistent access and deploy ransomware. The primary targets are organizations using Windows systems with Defender enabled, particularly in sectors like finance, healthcare, and government. Mitigation strategies include applying updates for related vulnerabilities, monitoring for suspicious activities, and implementing additional security measures.

Winsage

May 11, 2026

New GhostLock tool abuses Windows API to block file access

A security researcher has developed a proof-of-concept tool called GhostLock, which exploits a vulnerability in the Windows file API, specifically the 'CreateFileW' function. By manipulating the 'dwShareMode' parameter to grant exclusive access to files, GhostLock can prevent other users or applications from opening those files, resulting in a 'STATUSSHARINGVIOLATION' error. The tool automates the process of opening multiple files on SMB shares, causing access disruptions without requiring elevated privileges. This technique is intended as a disruption attack rather than a destructive one, similar to ransomware, and can serve as a diversion during intrusions. Detection of this attack relies on monitoring the open-file count with ShareAccess set to 0 at the file server layer. Dvash has provided resources for IT teams to enhance detection capabilities against this threat.

Winsage

April 10, 2026

Microsoft says Windows’ Secure Lock screen clock deliberately runs up to 30 seconds behind

Users have reported that the clock on the Secure Lock screen of Windows operating systems can lag by up to 30 seconds behind the actual time. Microsoft clarified that this behavior is an intentional design choice, as the Secure Lock screen operates on the Winlogon secure desktop under the SYSTEM account, causing the clock to refresh every 30 seconds. Other time-dependent functions in the system maintain accurate timekeeping. Microsoft has no plans to change this behavior, stating that it is a quirky feature of the Windows experience.

Winsage

April 2, 2026

Don’t blame Windows 11 updates for every problem, Microsoft veteran says

Corporate clients often report to Microsoft that Windows updates disrupt their systems, particularly after Patch Tuesday. A 2026 report from Omnissa indicates that Windows environments experience more application crashes and forced shutdowns than macOS. However, Raymond Chen, a Windows expert, suggests that many systems are already compromised before updates are installed. Engineers at Microsoft frequently find that issues persist even after rolling back updates, and similar failures can occur on machines that haven't received the update yet. The actual triggers for system failures often stem from changes made by IT departments prior to updates, such as new drivers or configuration modifications. These changes may not show immediate issues until a reboot occurs during Patch Tuesday, revealing existing instability. Best practices for IT admins include controlled change management, validating drivers and policies before deployment, using staged rollouts, rebooting after major changes, and maintaining logging and monitoring systems. Microsoft conducts extensive testing of updates to ensure system security and stability, and delaying updates can increase risks.

Winsage

January 27, 2026

Microsoft Phases Out RC4 in Kerberos to Boost Security

Microsoft is phasing out the RC4 encryption method used in Kerberos to address vulnerability CVE‑2026‑20833, which allows attackers to exploit weak encryption for offline cracking of service account passwords. The transition timeline includes an initial phase starting January 13, 2026, with new Kerberos audit events and optional registry controls to identify RC4 usage. In April 2026, domain controllers will default to AES‑SHA1, disabling fallback to RC4. By July 2026, Microsoft will remove Audit mode and enforce Enforcement mode, eliminating RC4 from the Kerberos protocol. Organizations are advised to update Active Directory Domain Controllers, monitor System event logs for new audit events, address KDCSVC events, and activate Enforcement mode to enhance security against RC4-related vulnerabilities.

Winsage

December 10, 2025

Beyond RC4 for Windows authentication

Two new PowerShell scripts from the Microsoft Kerberos-Crypto GitHub repository have been introduced to enhance cybersecurity by streamlining the monitoring of Security Event logs on domain controllers. 1. List-AccountKeys.ps1: This script queries the Security Event Log for the Keys field, enumerating the keys associated with accounts in the event logs. It provides details such as the timestamp, account name, account type, and specific account keys. For example, it can show that accounts have access to keys like RC4, AES128-SHA96, AES256-SHA96, and AES128-SHA256. 2. Get-KerbEncryptionUsage.ps1: This script allows users to query events to determine which encryption types Kerberos utilized, revealing requests that employed AES256-SHA96. It also offers filtering options for specific encryption algorithms, such as RC4. Organizations can further enhance their security by using SIEM solutions like Microsoft Sentinel or built-in Windows event forwarding to query these logs.

Winsage

November 19, 2025

Sysmon – Go-to Tool for IT Admins, Security Pros, and Threat Hunters Coming to Windows

Microsoft will integrate native System Monitor (Sysmon) functionality into Windows 11 and Windows Server 2025, enhancing security operations for IT teams. This integration will provide instant threat visibility, automate compliance through Windows Update, and include features such as process monitoring, network connection tracking, credential access detection, file system monitoring, process tampering detection, WMI persistence tracking, and custom configuration support. It will also offer official customer service support and allow seamless access to events through Windows Event Logs or Security Information and Event Management (SIEM) systems. Administrators can enable Sysmon using the command "sysmon -i." Future plans include expanding Sysmon’s capabilities with enterprise-scale management and AI-powered detection.

Winsage

November 19, 2025

Microsoft Integrates System Monitor (Sysmon) into Windows 11

Microsoft will integrate its forensic tool, System Monitor (Sysmon), into the Windows kernel with the upcoming releases of Windows 11 and Server 2025. This integration will transform Sysmon from a standalone utility into a native “Optional Feature” that will be serviced automatically through Windows Update. Administrators will no longer need to manually distribute Sysmon; instead, it can be activated through the “Turn Windows features on or off” dialog or command-line instructions. The integration will ensure that updates flow through the standard Windows Update pipeline, providing official support and Service Level Agreements (SLAs) for Sysmon. Microsoft plans to utilize local computing capabilities for AI inferencing to enhance security measures, focusing on detecting credential theft and lateral movement patterns. Sysmon will maintain backward compatibility with existing workflows, allowing the use of custom configuration files and adhering to the XML schema while continuing to log events to the Windows event log. Community-driven configuration repositories will remain operational, preserving established community knowledge.

Winsage

November 18, 2025

Microsoft is bringing native Sysmon support to Windows 11, Server 2025

Microsoft is integrating Sysmon into Windows 11 and Windows Server 2025, eliminating the need for separate deployments of Sysinternals tools. This integration will allow users to utilize custom configuration files for filtering captured events, which will be logged in the Windows event log. Sysmon is a free tool that monitors and blocks suspicious activities while logging events such as process creation, DNS queries, and executable file creation. It will be easily installable via the "Optional features" settings in Windows 11, with updates delivered through Windows Update. Sysmon will retain its standard features, including support for custom configuration files and advanced event filtering. Key events logged by Sysmon include process creation, network connections, process access, file creation, process tampering, and WMI events. Comprehensive documentation and new enterprise management features will be released next year.

Winsage

November 18, 2025

Microsoft to integrate Sysmon directly into Windows 11, Server 2025

Microsoft will integrate Sysmon into Windows 11 and Windows Server 2025, eliminating the need for standalone deployment. Sysmon will allow users to utilize custom configuration files for event filtering, logging events in the Windows event log. It tracks events such as process creation, DNS queries, executable file creation, changes to the clipboard, and auto-backup of deleted files. Users can access Sysmon through "Optional features" in Windows 11 and receive updates via Windows Update. Key events logged by Sysmon include process creation, network connections, process access, file creation, process tampering, and WMI events. Comprehensive documentation and new enterprise management features will be released next year.