Microsoft Defender ShieldBreak Elevation of Privilege Vulnerability Exploit

This module exploits the ShieldBreak local privilege escalation vulnerability in Microsoft Defender to execute a Core Impact agent with SYSTEM privileges. ShieldBreak bypasses the fix for the RoguePlanet vulnerability (CVE-2026-50656). The exploit combines the Windows Cloud Files API, Object Manager shadow directories and symbolic links, the Common Log File System, and Defender's privileged remediation workflow to redirect a file operation into the native Windows System32 directory. The module patches the ShieldBreak trigger with the full path of the staged Core Impact agent and executes the trigger from memory without writing ShieldBreak.exe to the target filesystem. The exploit creates a Cloud Files placeholder containing detected content and asks Defender to scan and remediate it through MpClient.dll. While remediation is in progress, it changes the placeholder contents and redirects the path used by Defender so the embedded payload is written as C:\Windows\System32\phoneinfo.dll. It then triggers the Windows Error Reporting scheduled task, which loads the payload as SYSTEM and launches the staged Core Impact agent. If an attempt does not install a SYSTEM agent, the module makes one additional attempt. The steps performed by the exploit are: Reads the Microsoft Defender engine version from the registry and verifies that it is version 1.1.26060.3008 or later. Generates and stages a Core Impact agent, patches the ShieldBreak trigger with its full path, and executes the trigger from memory. Creates a Cloud Files synchronization root and a placeholder backed by embedded detected content. Builds Object Manager shadow directories and symbolic links that make the scan path resolve through an attacker-controlled location. Calls Defender through MpClient.dll to scan the placeholder and begin privileged remediation. Coordinates Cloud Files hydration and CLFS file locking, then redirects Defender's file operation to C:\Windows\System32\phoneinfo.dll. Changes the hydrated placeholder to the embedded payload while Defender continues remediation using the redirected path. Triggers the \Microsoft\Windows\Windows Error Reporting\QueueReporting scheduled task so the payload is loaded as SYSTEM. Launches the patched Core Impact agent and verifies that the returned agent has SYSTEM privileges.