Qilin EDR killer infection chain

The analysis of this multi-stage malware loader reveals a sophisticated and stealthy approach to evading detection, particularly targeting Endpoint Detection and Response (EDR) systems. Here's a breakdown of its key features:

Stage 1: Initialization and Anti-Debugging

Initialization Routine:

• The loader begins by setting up an advanced exception handling mechanism that intercepts and bypasses EDR hooks on system APIs.
• It creates a custom dispatcher to handle exceptions, allowing it to execute arbitrary code during the process of resolving API calls.

Anti-Debugging Techniques:

• Breakpoint Check: Before overwriting the default exception handler, Stage 1 checks if there's a breakpoint set at KiUserExceptionDispatcher. If detected, it crashes the process.
• Geo-Fencing: The loader excludes systems configured for languages commonly used in post-Soviet countries by checking system locale settings.

Stealthy API Resolution:

• Instead of resolving ntdll!LdrProtectMrdata directly, the loader uses a known exported function (RtlDeleteFunctionTable) as an anchor to locate and resolve it stealthily.

Stage 1 Unpacking Mechanism

The loader creates two views of a paging file-backed

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