Note: SysAid was not compromised, and no SysAid vulnerability was involved. The attacker had already gained access to the victim environment and abused a legitimate software-deployment feature to deploy malware onto another machine within it. Key Points Check Point Research (CPR) tracks ‘ Cavern Manticore ’ as an Iran-nexus threat actor operating against Israeli targets , with a focus on the government and IT sectors. Cavern Manticore shares technical overlaps with other Iranian MOIS (Ministry of Intelligence and Security)-linked threat actors, including MuddyWater and Lyceum . CPR observed a modular C2 framework in the wild, with all samples built on top of .NET but compiled into different output formats. These components are used as Cavern agent and Cavern modules . The framework’s anti-analysis posture relies on uncommon .NET compilation formats ( Mixed-Mode C++/CLI and Native AOT ) that force reverse engineers into multiple toolsets and metadata-reconstruction workflows, together with per-module AppDomain isolation as an anti-forensics measure. In malware-engine coverage, the majority of observed samples score zero or very low detection rates on VirusTotal. Post-exploitation modules provide the threat actor with extended capabilities , including file system and database browsing, LDAP querying, network reconnaissance, and tunneling. In multiple observed intrusions, the initial foothold was achieved through abuse of existing Remote Monitoring and Management ( RMM ) software deployed in the targeted organization. Introduction Since early 2026, Check Point Research (CPR) has tracked a new modular command-and-control framework used by Cavern Manticore , an Iran-nexus APT group primarily targeting Israeli organizations, with a focus on IT providers, and government sectors. Cavern Manticore is an Iran MOIS (Ministry of Intelligence and Security)-linked actor, with links to the OilRig subgroup named Lyceum . The framework reflects a mature and adaptable toolset built around a shared .NET foundation, while using multiple compilation formats across different components, including .NET Framework , .NET Mixed-Mode C++/CLI , and .NET Native AOT . The compilation format itself becomes the anti-analysis layer that forces reverse engineers into multiple toolsets and metadata-reconstruction workflows. During our investigation, we observed both Cavern agents and Cavern modules in the wild, highlighting a modular architecture that separates core communication capabilities from mission-specific post-exploitation functionality. This design allows the operators to tailor deployments per victim environment, limit what defenders and analysts can recover from any single victim and extend access after compromise through specialized modules for reconnaissance, data access, tunneling, and lateral movement. Figure 1: Cavern Modules Evade Malware Engines. Technical Analysis: Cavern – A Modular .NET C2 Framework 1. Cavern at a Glance Cavern is a modular post-exploitation C2 framework built entirely on .NET, but deliberately compiled into three different binary formats: .NET Framework ( IL-only ), Mixed-Mode C++/CLI ( IL + Native ), and .NET 8 NativeAOT ( Native-only ). The recovered execution chain begins with SysAid’s software update feature, which the actor leverages to deploy a WinDirStat DLL sideloading package to C:\ProgramData\WinDir\WinDirStat.exe . The legitimate WinDirStat.exe binary loads the trojanized uxtheme.dll , which is the Cavern Agent , and the agent in turn loads a dedicated native communication module n-HTCommp.dll to reach the C2 and then pulls down additional post-exploitation modules on operator command. Figure 2: Cavern Agent Execution Chain. The table below provides an overview of the modules. Component Internal Name Format Role Cavern Agent uxtheme.dll Mixed-Mode C++/CLI (.NET 4.7.2, IL + Native) Core backdoor, module orchestrator Communication Module n-HTCommp.dll NativeAOT (.NET 8, Native-only) HTTPS/WebSocket transport, XOR…

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