Hunting For Process Injection Techniques

Hunting for Process Injection Techniques

Overview

Process injection (MITRE ATT&CK T1055) allows adversaries to execute code in the address space of another process, enabling defense evasion and privilege escalation. This skill detects injection techniques via Sysmon Event ID 8 (CreateRemoteThread), Event ID 10 (ProcessAccess with suspicious access rights), and analysis of source-target process relationships to distinguish legitimate from malicious injection.

When to Use

• When investigating security incidents that require hunting for process injection techniques
• When building detection rules or threat hunting queries for this domain
• When SOC analysts need structured procedures for this analysis type
• When validating security monitoring coverage for related attack techniques

Detection Gaps & Validation

• Evasions that produce NO Sysmon EID 8: thread hijacking (SetThreadContext), APC injection (QueueUserAPC/NtQueueApcThread, early-bird), mapping injection (NtMapViewOfSection), and process hollowing (NtUnmapViewOfSection + WriteProcessMemory) all skip CreateRemoteThread. They surface only as EID 10 ProcessAccess with PROCESS_VM_WRITE|PROCESS_VM_OPERATION|PROCESS_CREATE_THREAD.
• Userland-hook bypass: indirect/direct syscalls and unhooked NTDLL defeat EDR inline hooks, leaving little or no telemetry — corroborate with EID 7 (ImageLoad of unbacked/floating modules) and kernel ETW.
• EID 10 noise: CSRSS, lsass, AV/EDR, and debuggers legitimately open high-access handles. Tune to cross-process opens where GrantedAccess masks 0x1F0FFF/0x1FFFFF AND the source is unsigned or unusual; treat 0x1000/0x1400 read-only as benign.
• Validate the hunt fires: run Atomic Red Team T1055.001 (process hollowing), T1055.002, and mavinject.exe APC, then confirm EID 8 GrantedAccess and EID 10 access masks are captured.
• FP tuning: allowlist known injector→target pairs (e.g., MsMpEng.exe, vmtoolsd) by signer, not by image name alone.

Prerequisites

• Sysmon installed with Event IDs 8 and 10 enabled
• Process creation logs (Sysmon Event ID 1 or Windows 4688)
• Python 3.8+ with standard library
• JSON-formatted Sysmon event logs

Steps

1. Parse Sysmon Events — Ingest Event IDs 1, 8, and 10 from JSON log files
2. Detect CreateRemoteThread — Flag Event ID 8 with suspicious source-target process pairs
3. Analyze ProcessAccess Rights — Identify Event ID 10 with dangerous access masks (PROCESS_VM_WRITE, PROCESS_CREATE_THREAD)
4. Build Process Relationship Graph — Map source-to-target injection relationships
5. Filter Known Legitimate Pairs — Exclude known benign injection patterns (AV, debuggers, system processes)
6. Score Injection Severity — Apply risk scoring based on source process, target process, and access rights
7. Generate Hunt Report — Produce structured report with MITRE sub-technique mapping

Expected Output

• JSON report of detected injection events with severity scores
• Process injection relationship graph
• MITRE ATT&CK sub-technique mapping (T1055.001-T1055.012)
• False positive exclusion recommendations