Detecting Process Injection Techniques

When to Use

• EDR alerts on suspicious API call sequences (VirtualAllocEx + WriteProcessMemory + CreateRemoteThread)
• A legitimate process (explorer.exe, svchost.exe) exhibits unexpected network connections or file operations
• Memory forensics reveals executable code in memory regions that should not contain it
• Investigating living-off-the-land attacks where malware hides inside trusted processes
• Building detection logic for specific injection techniques in EDR or SIEM rules

Do not use for standard DLL loading analysis; injection implies unauthorized code placement in a process without that process's cooperation.

Prerequisites

• Volatility 3 for memory forensics analysis of injection artifacts
• Sysmon configured with Event IDs 8 (CreateRemoteThread) and 10 (ProcessAccess)
• API Monitor or x64dbg for observing injection API calls in real-time
• Process Hacker or Process Explorer for inspecting process memory regions
• Understanding of Windows memory management (VirtualAlloc, VAD, page protections)
• Isolated analysis environment for safe malware execution and monitoring

Workflow

Step 1: Identify Injection via Memory Forensics

Use Volatility to detect injected code in process memory:

# malfind: Primary injection detection plugin
vol3 -f memory.dmp windows.malfind

# malfind detects:
# - Memory regions with PAGE_EXECUTE_READWRITE (RWX) protection
# - PE headers (MZ signature) in non-image VAD entries
# - Executable memory not backed by a file on disk

# Filter by specific process
vol3 -f memory.dmp windows.malfind --pid 852

# Dump injected memory regions for analysis
vol3 -f memory.dmp windows.malfind --dump

# Check VAD (Virtual Address Descriptor) tree for anomalies
vol3 -f memory.dmp windows.vadinfo --pid 852

# Detect hollowed processes (mapped image doesn't match disk)
vol3 -f memory.dmp windows.hollowfind

Step 2: Classify the Injection Technique

Identify which injection method was used based on artifacts:

Process Injection Techniques and Detection Artifacts:
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

1. Classic DLL Injection
   APIs: OpenProcess -> VirtualAllocEx -> WriteProcessMemory -> CreateRemoteThread
   Artifact: Loaded DLL in target process not present in known-good baseline
   Detection: New DLL in dlllist not matching disk hash, CreateRemoteThread event

2. Process Hollowing (RunPE)
   APIs: CreateProcess(SUSPENDED) -> NtUnmapViewOfSection -> VirtualAllocEx ->
         WriteProcessMemory -> SetThreadContext -> ResumeThread
   Artifact: Process image in memory doesn't match file on disk
   Detection: hollowfind plugin, mismatched PE headers vs disk file

3. APC Injection
   APIs: OpenProcess -> VirtualAllocEx -> WriteProcessMemory -> QueueUserAPC
   Artifact: Alertable thread has queued APC pointing to injected code
   Detection: Thread start addresses outside known modules

4. Thread Hijacking
   APIs: OpenProcess -> VirtualAllocEx -> WriteProcessMemory ->
         SuspendThread -> GetThreadContext -> SetThreadContext -> ResumeThread
   Artifact: Thread instruction pointer changed to injected code
   Detection: Thread context modification, EIP/RIP outside module boundaries

5. Reflective DLL Injection
   APIs: VirtualAllocEx -> WriteProcessMemory -> CreateRemoteThread (to reflective loader)
   Artifact: DLL loaded in memory but NOT in loaded module list
   Detection: malfind (PE in non-image memory), module not in ldrmodules

6. Process Doppelganging
   APIs: NtCreateTransaction -> NtCreateFile(transacted) -> NtWriteFile ->
         NtCreateSection -> NtRollbackTransaction -> NtCreateProcessEx
   Artifact: Process created from transacted file that was rolled back
   Detection: Process with no corresponding file on disk

7. AtomBombing
   APIs: GlobalAddAtom -> NtQueueApcThread (with GlobalGetAtomName)
   Artifact: Code stored in global atom table, APC triggers copy to target
   Detection: Unusual atom table entries, APC injection indicators

Step 3: Detect Injection via Sysmon Events

Analyze Sysmon and Windows Event Log data:

# Sysmon Event ID 8: CreateRemoteThread
# Detect when one process creates a thread in another
wevtutil qe "Microsoft-Windows-Sysmon/Operational" \
  /q:"*[System[EventID=8]]" /f:text /c:20

# Sysmon Event ID 10: ProcessAccess
# Detect suspicious access rights to other processes

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