Microsoft Defender's Own Driver Can Be Weaponized to Delete Security Software at Boot
Check Point revealed BTR Reforged, a technique weaponizing Microsoft Defender's built-in BTR.sys driver to delete security software at boot without exploiting any vulnerability.
Check Point Research disclosed BTR Reforged, a technique that abuses BTR.sys, a legitimately signed Windows Defender boot-time remediation driver, to perform arbitrary kernel-level file and registry operations on Windows 7 through Windows 11 25H2 without exploiting a software flaw. The BTR_CLI proof-of-concept tool, presented at Black Hat USA 2026 and DEF CON 34, installs the driver via direct registry writes and executes deletions during the boot-time 'golden window' before Defender's user-mode services start, demonstrated by deleting the full Defender stack on a patched Windows 11 machine. Exploitation requires SeLoadDriverPrivilege; Microsoft confirmed it does not meet criteria for immediate servicing and no patch is planned. No evidence of real-world abuse was found, and related indicators of compromise via Sysmon events were published.
AI SIEM Search
Huntress launched AI Search for Managed SIEM, translating plain-English questions into ESQL log queries with schedulable custom alerts.
Huntress introduced AI Search in its Managed SIEM, letting users query logs in natural language instead of writing ESQL, KQL, or SPL. The feature generates a real ESQL query behind the scenes, exposes it for users to inspect and learn from, and allows saved searches to be scheduled as recurring alerts at hourly, daily, or weekly cadence. A planned next version will return summarized plain-language answers instead of raw logs.