CYFIRMA Research

CYFIRMA Research: Operation PhantomCLR- Stealth Execution via AppDomain Hijacking and In-Memory .NET Abuse

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Operation PhantomCLR

Our latest research uncovers a highly sophisticated post-exploitation framework that represents a significant shift in modern attacker tradecraft. The campaign leverages .NET AppDomainManager hijacking to abuse a legitimate, digitally signed Intel binary (IAStorHelp.exe), transforming it into a stealthy execution container without modifying the original file. 

This allows malicious code to execute within a trusted environment, effectively bypassing traditional EDR and antivirus defenses. The framework operates entirely in memory, combining advanced techniques, such as JIT-based shellcode execution, reflective DLL loading, and direct syscall usage, to evade detection while maintaining operational stealth.

Link to the Research Report:
https://www.cyfirma.com/research/operation-phantomclr-stealth-execution-via-appdomain-hijacking-and-in-memory-net-abuse/

#ThreatIntelligence #MalwareAnalysis #CyberSecurity #APT #ThreatHunting #MemoryForensics #CYFIRMA #CYFIRMAResearch #ETLM  #ExternalThreatLandscapeManagement

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