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

Tools & Systems

Common Scenarios

1. Svchost.exe Hollowing: Malware creates svchost.exe suspended, hollows it, injects backdoor code - process appears legitimate but behaves maliciously.
2. Explorer.exe Hollowing: Attacker hollows explorer.exe to inherit its network permissions and trusted process context.
3. Rundll32 Hollowing: Malicious loader creates rundll32.exe, replaces its memory with implant code for C2 beaconing.
4. Multi-Stage Hollowing: Loader uses process hollowing as first stage, then performs additional injection into services.

Output Format

Hunt ID: TH-HOLLOW-[DATE]-[SEQ]
Technique: T1055.012
Hollowed Process: [Process name and PID]
Original Binary: [Expected on-disk path]
Parent Process: [Parent name and PID]
Memory Mismatch: [Yes/No]
Suspicious APIs: [NtUnmapViewOfSection, WriteProcessMemory, etc.]
Network Activity: [C2 connections if any]
Host: [Hostname]
User: [Account context]
Risk Level: [Critical/High/Medium/Low]

Verification Criteria

Confirm successful execution by validating:

• [ ] All prerequisite tools and access requirements are satisfied
• [ ] Each workflow step completed without errors
• [ ] Output matches expected format and contains expected data
• [ ] No security warnings or misconfigurations detected
• [ ] Results are documented and evidence is preserved for audit

Compliance Framework Mapping

This skill supports compliance evidence collection across multiple frameworks:

• SOC 2: CC7.2 (Anomaly Detection), CC7.3 (Incident Identification)
• ISO 27001: A.12.4 (Logging & Monitoring), A.16.1 (Security Incident Management)
• NIST 800-53: SI-4 (System Monitoring), IR-4 (Incident Handling), RA-5 (Vulnerability Scanning)
• NIST CSF: DE.AE (Anomalies & Events), DE.CM (Continuous Monitoring), DE.DP (Detection Processes)

Claw GRC Tip: When this skill is executed by a registered agent, compliance evidence is automatically captured and mapped to the relevant controls in your active frameworks.

Deploying This Skill with Claw GRC

Agent Execution

Register this skill with your Claw GRC agent for automated execution:

# Install via CLI
npx claw-grc skills add detecting-process-hollowing-technique

# Or load dynamically via MCP
grc.load_skill("detecting-process-hollowing-technique")

Audit Trail Integration

When executed through Claw GRC, every step of this skill generates tamper-evident audit records:

• SHA-256 chain hashing ensures no step can be modified after execution
• Evidence artifacts (configs, scan results, logs) are automatically attached to relevant controls
• Trust score impact — successful execution increases your agent's trust score

Continuous Compliance

Schedule this skill for recurring execution to maintain continuous compliance posture. Claw GRC monitors for drift and alerts when re-execution is needed.