Detecting T1055 Process Injection With Sysmon

---
name: detecting-t1055-process-injection-with-sysmon
description: Use when detect process injection techniques (T1055) including classic
  DLL injection, process hollowing, and APC injection by analyzing Sysmon events for
  cross-process memory operations, remote thread creation, and anomalous DLL loading
  patterns. Use when detecting process injection techniques (t1055) including classic
  dll injection, process.
domain: cybersecurity
tags:
- threat-hunting
- process-injection
- sysmon
- mitre-t1055
- defense-evasion
- dll-injection
- process-hollowing
subdomain: threat-hunting
version: '1.0'
author: oyi77
license: Apache-2.0
d3fend_techniques:
- Executable Denylisting
- Execution Isolation
- File Metadata Consistency Validation
- Content Format Conversion
- File Content Analysis
nist_csf:
- DE.CM-01
- DE.AE-02
- DE.AE-07
- ID.RA-05
category: cybersecurity
---

# Detecting T1055 Process Injection With Sysmon

## Overview

Cybersecurity skill for detecting t1055 process injection with sysmon. Follows industry best practices and security standards.

## When to Use
**Trigger phrases:**
- "detecting t1055 process injection with sysmon"
- "Detect process injection techniques (T1055) including classic DLL injection, pro"


- When hunting for defense evasion techniques that hide malicious code inside legitimate processes
- After EDR alerts for suspicious cross-process memory access or remote thread creation
- When investigating malware that injects into svchost.exe, explorer.exe, or other system processes
- During purple team exercises testing detection of process injection variants
- When validating Sysmon configuration coverage for injection detection


## When NOT to Use

- When you lack proper authorization for testing
- For production systems without change management
- When the task requires legal or compliance expertise beyond technical scope


## Prerequisites

- Sysmon deployed with comprehensive configuration capturing Events 1, 7, 8, 10, 25
- Event ID 8 (CreateRemoteThread) enabled for remote thread detection
- Event ID 10 (ProcessAccess) configured with appropriate access mask filters
- Event ID 7 (ImageLoaded) for DLL injection detection
- Event ID 25 (ProcessTampering) for process hollowing on Sysmon 13+
- SIEM platform for correlation and alerting

## Workflow

```python
# Example: IOC detection
import re

IOC_PATTERNS = {
    "ip": r"\b(?:\d{1,3}\.){3}\d{1,3}\b",
    "domain": r"\b[a-z0-9-]+\.[a-z]{2,}\b",
    "hash_md5": r"\b[a-f0-9]{32}\b",
    "hash_sha256": r"\b[a-f0-9]{64}\b",
}

def extract_iocs(text: str) -> dict:
    return {k: re.findall(v, text) for k, v in IOC_PATTERNS.items()}
```

1. **Define Detection Scope** — Identify the specific t1055 process injection techniques or indicators to hunt. Map to MITRE ATT&CK tactics/techniques where applicable.
2. **Collect Baseline Data** — Gather historical logs and establish normal behavior patterns for t1055 process injection.
3. **Build Detection Queries** — Write sysmon queries targeting t1055 process injection indicators. Use platform-specific query language for optimal performance.
4. **Execute Hunts** — Run queries against the collected data, starting with broad filters and narrowing down.
5. **Triage Results** — Investigate alerts, filter false positives, and validate findings against known-good behavior.
6. **Document Findings** — Record confirmed detections, IOCs, and affected systems. Update detection rules based on findings.

## Tools

- **sysmon** — Primary tool for this skill
- **SIEM Platform** — Central log aggregation and query execution
- **Sigma Rules** — Vendor-agnostic detection rule format
- **MITRE ATT&CK Navigator** — Technique mapping and coverage analysis


## Process

1. **Reconnaissance** — Gather target information, identify attack surface, enumerate services
1. **Analysis/Exploitation** — Execute the technique, analyze results, document findings
1. **Reporting** — Document IOCs, write findings, provide remediation recommendations

## Verification

- [ ] All t1055 process injection procedures executed completely and documented
- [ ] Findings validated against multiple data sources
- [ ] False positives identified and filtered
- [ ] Results documented with evidence and timestamps
- [ ] Recommendations provided with risk-based prioritization

## Anti-Rationalization Table

| Rationalization | Reality |
|---|---|
| "We are too small to be targeted" | Automated attacks target everyone. Size does not matter. |
| "Security slows us down" | A breach slows you down 100x more. Build security in from the start. |
| "We will fix it after launch" | Vulnerabilities in production are exploited within hours. Fix before deploy. |