Nightmare-Eclipse, also known as Chaotic Eclipse, has unveiled ShieldBreak, a new Windows zero-day exploit targeting the RoguePlanet privilege-escalation flaw. The release comes after Microsoft had already issued a July update to address RoguePlanet, which is described as a check-then-act timing issue in mpengine.dll, Defender's scanning engine. A local attacker could exploit the narrow gap between validation and use of a file-related object to redirect scanning flow towards attacker-controlled behavior, ultimately launching a command shell under NT AUTHORITY\SYSTEM.
The company’s remediation came with Malware Protection Engine version 1.1.26060.3008, which blocked only one route into the vulnerable processing path rather than removing the broader synchronization failure in practice.
The proof-of-concept combines Common Log File System (CLFS) log manipulation with object manager symbolic links to mislead Defender's scanning pipeline into holding a lock on legitimate system files, such as phonefo.dll, while an attacker substitutes a malicious counterpart beneath it. A claimed 100% success rate is noteworthy for a race-condition exploit since timing-dependent techniques fail before an attacker can catch the required execution window. Even so, dependable local privilege escalation on current Windows releases would increase risk after initial access, allowing malware operators to disable controls, establish persistence, and access protected resources.
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