Analyzing Malicious URL with URLScan

What Is This Skill?

The "Analyzing Malicious URL with URLScan" skill focuses on leveraging URLScan.io, a web-based service designed for the safe analysis of suspicious URLs. URLScan.io enables security professionals to submit URLs for investigation in an isolated environment, capturing crucial artifacts such as screenshots, DOM content, HTTP transactions, JavaScript execution, and external network connections. This skill guides users on how to utilize both the URLScan web interface and its API to efficiently analyze potentially malicious URLs without risking exposure to their local systems.

URLScan.io is particularly powerful for identifying phishing attempts, credential harvesting pages, drive-by downloads, and other web-based threats. By using this skill, analysts can gain actionable intelligence about how a suspicious URL behaves, what resources it loads, and whether it exhibits characteristics of known attack campaigns.

Why Use URLScan for Malicious URL Analysis?

Traditional URL analysis can expose analysts to risk if performed directly on their machines. Malicious URLs may deliver payloads, exploit browser vulnerabilities, or redirect to additional harmful domains. URLScan.io mitigates these risks by providing a cloud-based, sandboxed environment for execution and observation of URL behavior.

Key reasons to use URLScan.io for malicious URL analysis include:

• Isolation: Ensures the analyst’s workstation is never directly exposed to the potentially harmful content of the URL.
• Comprehensive Data Collection: Automatically collects screenshots, DOM structure, HTTP request and response data, network connections, and JavaScript activity.
• Threat Intelligence Integration: Enriches results with threat feeds, blocklists, and community reports, helping analysts quickly assess risk.
• Automation Support: Offers an API for integrating URL analysis into security operations workflows or SIEM/SOAR platforms.
• Incident Response: Provides structured reports that are easily shareable among incident response teams.

How to Use URLScan for Malicious URL Analysis

Prerequisites

• A free URLScan.io account (API key required for API submissions)
• Python 3.8+ with the requests library installed (for scripting)
• Basic understanding of HTTP and web technologies

Submitting a URL via Web Interface

1. Navigate to the URLScan.io Website
   Visit https://urlscan.io/.

2. Submit the Suspicious URL
   Enter the URL you wish to analyze in the search bar and select "Public Scan" or "Private Scan" as appropriate.

3. Review the Results
   After submission, URLScan processes the URL and presents a scan result page. This includes:

   • A screenshot of the page rendered in a sandbox
   • DOM content and resource loading details
   • HTTP request and response timelines
   • Outbound network connections
   • Community and threat intelligence annotations

4. Investigate Artifacts
   Use the provided data to inspect for phishing forms, suspicious scripts, or anomalous network activity.

Submitting a URL via the API

Automating URL submissions and retrieving results is straightforward using Python and the URLScan API.

Example: Submitting a URL for Scanning

import requests

API_KEY = 'YOUR_URLSCAN_API_KEY'
URL_TO_SCAN = 'http://suspicious.example.com/'

headers = {
    'API-Key': API_KEY,
    'Content-Type': 'application/json'
}

data = {
    'url': URL_TO_SCAN,
    'public': 'on'  # Use 'off' for private scans
}

response = requests.post('https://urlscan.io/api/v1/scan/', headers=headers, json=data)
result = response.json()
print('Scan UUID:', result.get('uuid'))
print('Result URL:', result.get('result'))

Example: Retrieving Scan Results

import requests

SCAN_UUID = 'your-scan-uuid'

response = requests.get(f'https://urlscan.io/api/v1/result/{SCAN_UUID}/')
scan_data = response.json()

## Example:

Print the page title and main verdict
print('Page Title:', scan_data.get('page', {}).get('title'))
print('Verdicts:', scan_data.get('verdicts', {}))

Interpreting Results

• Screenshots: Quickly identify phishing page design or look-alike branding.
• HTTP Transactions: Examine suspicious redirects, credential POST requests, or malicious file downloads.
• Network Connections: Spot connections to known bad infrastructure or unusual domains.
• DOM and JavaScript: Detect obfuscated scripts or injected content commonly used in attacks.

When to Use This Skill

• During Incident Response: When a user reports a suspicious link in an email, chat message, or document.
• Threat Hunting and Intelligence: To enrich indicators of compromise (IOCs) and uncover attacker infrastructure.
• Email and Web Security Testing: To validate detection rules or simulate attack scenarios in a controlled way.
• Security Operations Center (SOC) Playbooks: As part of structured response procedures for phishing and social engineering campaigns.
• Red and Blue Team Exercises: To analyze simulated or real malicious URLs in tabletop or live fire drills.

Important Notes

• Privacy and Data Sharing: Public scans are visible to all URLScan.io users. Use private scans for sensitive investigations.
• API Usage Limits: The free API tier has rate limits. Review URLScan.io documentation for quotas and upgrade options.
• False Positives/Negatives: Automated analysis may sometimes misclassify benign or malicious behavior. Always corroborate with manual review.
• Legal and Ethical Use: Only submit URLs that you are authorized to investigate. Avoid scanning personal or confidential URLs without proper consent.
• Continuous Learning: URLScan evolves with new features and integrations. Stay updated with their documentation and community insights.

By mastering this skill, analysts can safely and effectively analyze suspicious URLs, improve threat detection capabilities, and reduce the risk of compromise from phishing and web-based attacks.