detecting-process-hollowing-technique

name	detecting-process-hollowing-technique
description	Detect process hollowing (MITRE T1055.012) by analyzing memory-mapped sections, hollowed process indicators, and parent-child anomalies using EDR telemetry, Volatility's malfind plugin, pe-sieve, Hollows Hunter, and Sysmon Event ID 25. Use when investigating a legitimate-looking process (svchost.exe, explorer.exe, rundll32.exe) suspected of hosting injected code via NtUnmapViewOfSection.
domain	cybersecurity
subdomain	threat-hunting
tags	["threat-hunting","mitre-attack","process-hollowing","process-injection","edr","t1055","proactive-detection"]
version	1.0
author	mahipal
license	Apache-2.0
d3fend_techniques	["Platform Monitoring","Process Code Segment Verification","Segment Address Offset Randomization","Process Analysis","Application Hardening"]
nist_csf	["DE.CM-01","DE.AE-02","DE.AE-07","ID.RA-05"]
mitre_attack	["T1046","T1057","T1082","T1083","T1055"]

Detecting Process Hollowing Technique

When to Use

• When investigating suspected fileless malware or in-memory threats
• After EDR alerts on process injection or suspicious memory operations
• When hunting for defense evasion techniques in a compromised environment
• When threat intel reports indicate process hollowing in active campaigns
• During purple team exercises validating T1055.012 detection coverage

Prerequisites

• EDR with memory protection monitoring (CrowdStrike, MDE, SentinelOne)
• Sysmon with Event IDs 1 (Process Create), 8 (CreateRemoteThread), 25 (ProcessTampering)
• Windows ETW providers for process hollowing (Microsoft-Windows-Kernel-Process)
• Memory forensics capabilities (Volatility, WinDbg)
• Process integrity monitoring tools

Workflow

1. Understand Hollowing Mechanics: Process hollowing involves creating a legitimate process in suspended state, unmapping its memory, writing malicious code, then resuming execution.
2. Monitor Suspended Process Creation: Hunt for processes created with CREATE_SUSPENDED flag followed by memory writes and thread resumption.
3. Detect Memory Section Anomalies: Identify processes where the in-memory image differs from the on-disk binary (image mismatch).
4. Analyze Parent-Child Process Trees: Flag processes whose behavior does not match their binary name (e.g., svchost.exe making unusual network connections).
5. Check Process Integrity: Compare process memory sections against the legitimate binary on disk.
6. Correlate with Network Activity: Hollowed processes often establish C2 connections - correlate suspicious process behavior with network logs.
7. Document and Contain: Report findings, isolate affected endpoints, and update detection rules.

Key Concepts

Concept	Description
T1055.012	Process Injection: Process Hollowing
T1055	Process Injection (parent technique)
T1055.001	DLL Injection
T1055.003	Thread Execution Hijacking
T1055.004	Asynchronous Procedure Call
CREATE_SUSPENDED	Windows flag to create a process in suspended state