Reflective Code Loading

When a detection for this fires

What the technique is

Adversaries may reflectively load code into a process in order to conceal the execution of malicious payloads. Reflective loading involves allocating then executing payloads directly within the memory of the process, vice creating a thread or process backed by a file path on disk (e.g., Shared Modules). Reflectively loaded payloads may be compiled binaries, anonymous files (only present in RAM), or just snubs of fileless executable code (ex: position-independent shellcode). For example, the Assembly.Load() method executed by PowerShell may be abused to load raw code into the running process. Reflective code injection is very similar to Process Injection except that the “injection” loads code into the processes’ own memory instead of that of a separate process. Reflective loading may evade process-based detections since the execution of the arbitrary code may be masked within a legitimate or otherwise benign process. Reflectively loading payloads directly into memory may also avoid creating files or other artifacts on disk, while also enabling malware to keep these payloads encrypted (or otherwise obfuscated) until execution.

What MITRE says you would watch

• AN0838

  Detect anomalous chains of memory allocation and execution inside the same process (e.g., VirtualAlloc → memcpy → VirtualProtect → CreateThread). Unlike process injection, reflective code loading does not perform cross-process memory writes — the suspicious activity occurs entirely within the process’s own PID context.

• AN0839

  Monitor for in-process mmap + mprotect + execve/execveat activity where memory permissions are changed from writable to executable inside the same process without a corresponding ELF on disk.

• AN0840

  Suspicious calls to dlopen(), dlsym(), or mmap with RWX flags in processes that do not typically perform dynamic module loading. Monitor anonymous memory regions executed by user processes.