ShieldBreak PoC Bypasses RoguePlanet Fix to Gain SYSTEM via Windows Defender

NightmareEclipse released ShieldBreak, a proof-of-concept local privilege-escalation exploit claimed to bypass Microsoft’s fix for CVE-2026-50656 (RoguePlanet). The exploit allegedly abuses improper link resolution during Windows Defender remediation, combining Cloud Files placeholders, Object Manager symbolic-link swaps, CLFS path handling, an EICAR-triggered scan, and NTFS alternate data streams to redirect a Defender process running as SYSTEM and plant C:\Windows\System32\phoneinfo.dll. A fabricated Windows Error Reporting report and the QueueReporting scheduled task then cause wermgr.exe to load the malicious DLL; the included Warden.dll payload reportedly duplicates a SYSTEM token and opens a SYSTEM shell in the unprivileged user’s session.

Splunk published attack data and multiple disabled-by-default analytics for the ShieldBreak chain, covering Defender activity on \globalroot\ object-manager paths (Defender Operational events 1116/1117), MpClient.dll loaded by non-Defender processes, ADS creation through loopback administrative SMB shares (Security event 5145), manually created .wer files in the Windows Error Reporting ReportQueue, creation of phantom DLLs such as phoneinfo.dll in system paths, and WerMgr.exe spawning SYSTEM-integrity children. Organizations should collect the required Sysmon, Security, and Defender Operational telemetry; enable file-share object-access auditing; investigate these signals promptly; and validate the creating process, signer, file hash, and operational need before suppressing alerts.