Microsoft Bites Bullet as ShieldBreak Vulnerability Exposes Windows Defender Flaw
Microsoft has been hit with yet another security vulnerability, this time involving its Windows Defender cloud hydration feature. The flaw, dubbed ShieldBreak by researcher Nightmare Eclipse, allows a low-privileged attacker to gain system-level control.
The exploit manipulates the Defender's cloud-hydration process using mechanisms in the Common Log File System and path manipulation to swap file identity and hydration data.
As a result, an attacker-controlled DLL is placed in a sensitive folder, allowing it to bypass User Account Control and modify System-level files. This vulnerability echoes earlier concerns raised by researcher Will Dormann regarding the RoguePlanet exploit.
Microsoft has confirmed awareness of the issue and is actively investigating its validity. The company emphasized coordinated vulnerability disclosure and promised to patch impacted products as soon as possible.