<!-- Copyright (c) 2026 defconxt. All rights reserved. -->
<!-- Licensed under AGPL-3.0 — see LICENSE file for details. -->
<!-- NERF is a trademark of defconxt. -->
---
name: reverse-engineering-network-protocols
description: >-
  Reverse engineer proprietary and undocumented network protocols through traffic capture, message format analysis, and behavioral modeling.
domain: cybersecurity
subdomain: reverse-engineering
tags:
  - protocol-analysis
  - wireshark
  - network-reversing
  - pcap
  - dissector
version: "1.0"
author: defconxt
license: AGPL-3.0
metadata:
  mitre-attack: ["T1071"]
  cwe: ["CWE-327"]
  tools: ["Wireshark", "tshark", "Scapy", "mitmproxy", "ncrack"]
---

# Reverse Engineering Network Protocols

## Overview

Reverse engineer proprietary and undocumented network protocols through traffic capture, message format analysis, and behavioral modeling.

## Prerequisites

| Tool / Requirement | Details |
|---|---|
| `Wireshark` | Security tooling |
| `tshark` | Security tooling |
| `Scapy` | Security tooling |
| `mitmproxy` | Security tooling |
| `ncrack` | Security tooling |
| Isolated lab environment for testing | Environment requirement |
| Authorization and signed Rules of Engagement (RoE) | Environment requirement |
| Relevant target samples or systems acquired through authorized channels | Environment requirement |

## Quick Reference

```bash
# Capture protocol traffic
tshark -i eth0 -f "port 4444" -w capture.pcap

# Analyze with Wireshark dissector
tshark -r capture.pcap -T fields -e data.data

# Scapy protocol analysis
python3 -c "
from scapy.all import *
pkts = rdpcap('capture.pcap')
for p in pkts:
    if Raw in p:
        print(p[Raw].load.hex())
"
```

## Workflow

### Step 1: Preparation and Reconnaissance

```bash
# Identify target and gather initial intelligence
file ./target_sample
wireshark --version 2>/dev/null || echo "Install Wireshark"

# Set up working directory
mkdir -p /tmp/reverse-engineering-network-protocols/{output,logs,artifacts}
```

### Step 2: Primary Analysis

```bash
# Execute primary analysis with Wireshark
# Refer to Quick Reference above for detailed commands
echo "[*] Running Reverse Engineering Network Protocols with Wireshark..."

# Log all operations
script -q /tmp/reverse-engineering-network-protocols/logs/session.log
```

### Step 3: Deep Investigation

```bash
# Apply tshark for secondary analysis
echo "[*] Deep investigation with tshark..."

# Cross-reference findings
diff /tmp/reverse-engineering-network-protocols/output/primary.json /tmp/reverse-engineering-network-protocols/output/secondary.json
```

### Step 4: Documentation and Reporting

```bash
# Generate structured findings report
cat <<'EOF' > /tmp/reverse-engineering-network-protocols/output/report.json
{
  "technique": "reverse-engineering-network-protocols",
  "domain": "reverse-engineering",
  "tools_used": ["Wireshark", "tshark"],
  "findings": [],
  "recommendations": []
}
EOF
```

## Detection

```yaml
title: Reverse Engineering Network Protocols Detection
id: 1e1ef3c4-99c8-4c5c-8d6b-a93fcc1ed424
status: experimental
description: Detects suspicious activity related to reverse engineering network protocols techniques in reverse engineering context
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    CommandLine: "*reverse*engineering*"
  condition: selection
level: medium
tags:
  - attack.t1071
  - attack.defense_evasion
falsepositives:
  - Malware analysis sandbox performing automated binary inspection
```


**Detection Opportunities**

| Indicator | Source | Detection Logic |
|---|---|---|
| Reverse Engineering Network Protocols Detection | windows/process_creation | Sigma rule (medium) |
| ATT&CK Coverage | MITRE ATT&CK | T1071 |

## Verification

- [ ] Environment and tools verified and operational
- [ ] Target samples acquired through authorized channels
- [ ] Primary analysis completed with findings documented
- [ ] Secondary validation performed with independent tooling
- [ ] All artifacts preserved in structured output directory
- [ ] Detection opportunities documented for blue team

## References

- [MITRE ATT&CK T1071](https://attack.mitre.org/techniques/T1071) — Related technique
- [Wireshark Documentation](https://wireshark.org/) — Primary tooling
- [tshark Reference](https://tshark.org/) — Secondary tooling
