mitm-capture

name	mitm-capture
description	A mitmproxy-based tool for capturing mobile-app network traffic, detecting encrypted parameters, and analyzing APIs.

MITM Capture — Mobile App Traffic Capture and Analysis

An automated, mitmproxy-based capture tool for intercepting and analyzing a mobile app's network requests, detecting encrypted parameters, and generating a structured analysis report. Suited to API reverse-engineering of Android/iOS apps.

Tool Location

<mitm-capture-dir>/

Prerequisites

pip install mitmproxy rich pyyaml
# or
cd <mitm-capture-dir> && pip install -r requirements.txt

The device must be configured with a Wi-Fi proxy pointing to the IP:8080 of the machine running mitmproxy, and the mitmproxy CA certificate must be installed. Run bash setup.sh for the full configuration guide.

Command Reference

Start Capture

cd <mitm-capture-dir>

# Basic start (listens on 0.0.0.0:8080)
python cli.py start

# Specify the port and target domain
python cli.py start --port 9090 --domain api.example.com

# Transparent proxy mode
python cli.py start --transparent

Once started, the terminal displays a live, color-coded request log:

• HTTP methods are color-coded (GET=green, POST=cyan, DELETE=red)
• Status codes are colored (2xx=green, 3xx=yellow, 4xx/5xx=red)
• Auth headers are highlighted in yellow
• Encrypted parameters are flagged with a red warning

Data is saved automatically as JSONL files to output/{domain}/{timestamp}.jsonl.

Analysis Report

# Analyze and print to the terminal
python cli.py analyze output/

# Output to a Markdown file
python cli.py analyze output/ -o report.md

# Analyze data for a specific domain
python cli.py analyze output/api.example.com/ -o report.md

The report includes:

• Per-domain request statistics
• Authentication-method analysis
• API endpoint documentation (templated paths, e.g. /restaurants/{id})
• Encrypted-parameter detection results
• Frida hook suggestions

Export

# Export as cURL commands
python cli.py export output/ -f curl -o requests.sh

# Export as a HAR file
python cli.py export output/ -f har -o capture.har

# Export only a specific domain and method
python cli.py export output/ -f curl --domain api.example.com --method POST

Filter

# Filter by domain
python cli.py filter output/ --domain api.example.com

# Filter by method + path
python cli.py filter output/ --method POST --path "/api/v2"

# Show only requests with an auth header
python cli.py filter output/ --has-auth -o auth_requests.jsonl

# Filter by status code
python cli.py filter output/ --status 200

Configuration

Edit config.yaml to customize:

• Excluded domains: by default, noise domains such as googleapis, facebook, and analytics are excluded
• Whitelisted domains: set include_domains to capture only the listed domains
• Encryption-detection rules: suspicious parameter names (sign, token, encrypt, etc.) and value patterns (Base64, MD5, SHA256, JWT)
• Output settings: organize directories by domain, maximum body size

Agent Workflow

Standard Capture-and-Analyze Flow

1. Start capture: python cli.py start --domain <target>
2. Operate the app: exercise the target app's key features on the phone
3. Stop capture: stop with Ctrl+C; a session summary is generated automatically
4. Generate report: python cli.py analyze output/ -o report.md
5. Review the report: read report.md, focusing on encrypted parameters and authentication methods
6. Export to reproduce: python cli.py export output/ -f curl to generate reproducible cURL

Integration with Other Skills

MITM → Frida (tracing encrypted parameters)

When the report detects encrypted parameters:

1. Read the Frida Hook Suggestions section of the report
2. Use the resources/frida_crypto_hooks.js template
3. Combine with the frida-hooking skill to write a targeted hook script
4. Run the Frida hook and the MITM capture together to compare plaintext against ciphertext

Full JADX → MITM → Frida → IDA Chain

1. JADX: statically analyze to find the network-request classes and encryption methods
2. MITM: capture traffic to confirm the actual request format and encrypted parameters
3. Frida: hook the encryption methods found in JADX to capture their inputs and outputs
4. IDA: if the encryption is in native code, use the Frida offset to analyze the algorithm in IDA

MITM → web-api-analyzer Comparison

For platforms that have both an app and a web version:

1. Capture the app's traffic with mitm-capture
2. Capture the web version's traffic with web-api-analyzer
3. Compare the API differences and encryption-strategy differences between the two

JSONL Data Format

One JSON object per line:

{
  "timestamp": "2026-02-13T14:00:00.123456",
  "method": "POST",
  "url": "https://api.example.com/v2/search",
  "host": "api.example.com",
  "path": "/v2/search?sign=abc123",
  "request": {
    "headers": {"content-type": "application/json", "authorization": "Bearer xxx"},
    "body": "{\"keyword\": \"test\"}"
  },
  "response": {
    "status_code": 200,
    "headers": {"content-type": "application/json"},
    "body": "{\"results\": [...]}"
  }
}

Troubleshooting

Issue	Solution
The phone can't connect to the proxy	Confirm the phone and computer are on the same network; check the firewall
HTTPS requests show errors	Install the mitmproxy CA certificate on the device; Android 7+ requires a system-level certificate or a Frida-based SSL pinning bypass
Some requests aren't captured	Check the exclusion rules in config.yaml, or use the --domain parameter to specify the target
The output directory is empty	Confirm the proxy is configured correctly and the app is making network requests