What it does. URLScan.io is a free service for scanning and analyzing suspicious URLs. Part of mukul975/Anthropic-Cybersecurity-Skills (817 security skills) (mukul975/Anthropic-Cybersecurity-Skills).
Install
npx skills add mukul975/Anthropic-Cybersecurity-Skills --skill analyzing-malicious-url-with-urlscan, or copy the skill folder into ~/.claude/skills/analyzing-malicious-url-with-urlscan/.- Raw file:
curl -sL https://raw.githubusercontent.com/mukul975/Anthropic-Cybersecurity-Skills/HEAD/skills/analyzing-malicious-url-with-urlscan/SKILL.md
SKILL.md (verbatim)
1 placeholder credential was shortened (for example to api_key=YOUR_KEY) to pass the site's secret filter.
name: analyzing-malicious-url-with-urlscan
description: URLScan.io is a free service for scanning and analyzing suspicious URLs.
It captures screenshots, DOM content, HTTP transactions, JavaScript behavior, and
network connections of web pages in an isolat
domain: cybersecurity
subdomain: phishing-defense
tags:
- phishing
- email-security
- social-engineering
- dmarc
- awareness
- url-analysis
- threat-intelligence
version: '1.0'
author: mahipal
license: Apache-2.0
atlas_techniques:
- AML.T0052
nist_csf:
- PR.AT-01
- DE.CM-09
- RS.CO-02
- DE.AE-02
mitre_attack:
- T1566.002
- T1204.001
- T1598.003
Analyzing Malicious URL with URLScan
Overview
URLScan.io is a free service for scanning and analyzing suspicious URLs. It captures screenshots, DOM content, HTTP transactions, JavaScript behavior, and network connections of web pages in an isolated environment. This skill covers using URLScan's web interface and API to investigate phishing URLs, credential harvesting pages, and malicious redirects without exposing the analyst's system to risk.
When to Use
- When investigating security incidents that require analyzing malicious url with urlscan
- When building detection rules or threat hunting queries for this domain
- When SOC analysts need structured procedures for this analysis type
- When validating security monitoring coverage for related attack techniques
Prerequisites
- URLScan.io account (free tier available, API key for automation)
- Python 3.8+ with requests library
- Understanding of HTTP protocols and web technologies
- Familiarity with phishing URL patterns
Key Concepts
URLScan Capabilities
- Safe browsing: Renders URLs in isolated Chromium instance
- Screenshot capture: Visual snapshot of the rendered page
- DOM analysis: Full HTML content after JavaScript execution
- Network log: All HTTP requests made by the page (HAR format)
- Certificate analysis: SSL/TLS certificate details
- Technology detection: Identifies web frameworks and libraries
- IP/ASN mapping: Infrastructure intelligence
- Verdict: Community and automated classification
Phishing URL Red Flags
- Newly registered domains (< 30 days)
- Free hosting services (Wix, GitHub Pages, Firebase)
- URL shorteners hiding final destination
- Excessive subdomain depth (login.microsoft.com.evil.com)
- Brand name in subdomain or path, not domain
- Non-standard ports
- Data URIs or base64-encoded content
- JavaScript-heavy pages with minimal HTML
Workflow
Step 1: Submit URL to URLScan
Web: Navigate to https://urlscan.io and submit the suspicious URL
API: POST https://urlscan.io/api/v1/scan/
Header: API-Key: YOUR_KEY
Body: {"url": "https://suspicious-url.com", "visibility": "private"}
Step 2: Analyze Results
- Review screenshot for brand impersonation
- Check redirects and final destination URL
- Examine DOM for credential input forms
- Review network requests for data exfiltration endpoints
- Check SSL certificate validity and issuer
- Domains and IPs contacted
- URLs in redirect chain
- SHA-256 hashes of page resources
- JavaScript file hashes
Step 4: Cross-Reference with Threat Intelligence
Use the scripts/process.py to automate URL scanning, extract IOCs, and cross-reference with VirusTotal, PhishTank, and Google Safe Browsing.
Validation
- Successfully scan a suspicious URL via API
- Extract screenshot and identify brand impersonation
- Document complete redirect chain
- Generate IOC list from scan results
- Cross-reference findings with at least 2 threat intelligence sources
Other files in this skill
assets/template.md (verbatim)
URL Analysis Report Template
- Analyst: [Name]
- Date: [YYYY-MM-DD]
- Case ID: [CASE-XXXX]
- Source: [User report / Email gateway / SIEM alert]
URL Details
| Field |
Value |
| Original URL |
|
| Defanged URL |
hxxps://... |
| Final URL (after redirects) |
|
| URLScan UUID |
|
| Scan visibility |
private/public |
Page Analysis
| Field |
Value |
| Page Title |
|
| HTTP Status |
|
| Server |
|
| Domain |
|
| IP Address |
|
| ASN |
|
| Country |
|
| Login Form Detected |
Yes/No |
TLS Certificate
| Field |
Value |
| Issuer |
|
| Subject |
|
| Valid From |
|
| Valid To |
|
| Certificate Age |
|
Redirect Chain
| # |
URL |
Status |
| 1 (original) |
|
|
| 2 |
|
|
| 3 (final) |
|
|
Threat Intelligence Cross-Reference
| Source |
Result |
Score |
| URLScan Verdict |
|
|
| VirusTotal |
/XX engines |
|
| PhishTank |
|
|
| Google Safe Browsing |
|
|
| AbuseIPDB |
|
|
Domains
IP Addresses
| IP |
ASN |
Country |
Reputation |
|
|
|
|
File Hashes
Classification
Recommended Actions
Notes
[Additional analysis observations]
references/api-reference.md (verbatim)
1 placeholder credential shortened to pass the site's secret filter.
API Reference: urlscan.io URL Analysis
Base URL
https://urlscan.io/api/v1
Authentication
API-Key: YOUR_KEY
Submit Scan
POST /scan/
{"url": "https://example.com", "visibility": "private"}
| Field |
Values |
Description |
url |
URL string |
URL to scan |
visibility |
public/unlisted/private |
Scan visibility |
Response: {"uuid": "...", "result": "https://urlscan.io/result/UUID/", "api": "..."}
Get Result
GET /result/{uuid}/
Returns 404 while scanning, 200 when complete.
Search
GET /search/?q=domain:example.com&size=100
Query fields: domain:, ip:, server:, country:, filename:, hash:
Result Structure
| Field |
Description |
page.url |
Final URL after redirects |
page.domain |
Domain name |
page.ip |
Resolved IP |
page.country |
Server country |
page.status |
HTTP status code |
page.title |
Page title |
page.server |
Server header |
page.tlsIssuer |
TLS certificate issuer |
verdicts.overall.malicious |
Boolean malicious verdict |
verdicts.overall.score |
Risk score (0-100) |
lists.ips |
List of contacted IPs |
lists.certificates |
TLS certificates observed |
stats.resourceStats |
Resource type statistics |
Screenshot
GET /screenshots/{uuid}.png
DOM Snapshot
GET /dom/{uuid}/
Rate Limits
- Free: 100 scans/day, 1000 searches/day
- Paid: Higher limits per plan
references/standards.md (verbatim)
Standards & References: Analyzing Malicious URLs with URLScan
MITRE ATT&CK References
- T1566.002: Phishing: Spearphishing Link
- T1204.001: User Execution: Malicious Link
- T1608.005: Stage Capabilities: Link Target
- T1071.001: Application Layer Protocol: Web Protocols
- T1102: Web Service (for C2 via web)
URLScan.io API Reference
| Endpoint |
Method |
Description |
/api/v1/scan/ |
POST |
Submit URL for scanning |
/api/v1/result/{uuid}/ |
GET |
Get scan results |
/api/v1/search/?q= |
GET |
Search scan database |
/api/v1/result/{uuid}/screenshot/ |
GET |
Get page screenshot |
/api/v1/result/{uuid}/dom/ |
GET |
Get rendered DOM |
Search Query Syntax
domain:example.com - Search by domainip:1.2.3.4 - Search by IPserver:nginx - Search by web serverfilename:login.php - Search by filenamehash:abc123 - Search by resource hashpage.domain:example.com AND date:>now-7d - Combined queries
Industry Standards
- NIST SP 800-83: Guide to Malware Incident Prevention and Handling
- NIST SP 800-86: Guide to Integrating Forensic Techniques into Incident Response
- RFC 3986: Uniform Resource Identifier (URI) syntax
URL Classification Indicators
| Indicator |
Risk Level |
Description |
| Domain age < 7 days |
Critical |
Very recently registered |
| Domain age < 30 days |
High |
Recently registered |
| Free TLS cert (Let's Encrypt) with brand impersonation |
High |
Common phishing pattern |
| URL shortener |
Medium |
Obfuscates destination |
| Credential input form on non-brand domain |
Critical |
Credential harvesting |
| JavaScript obfuscation |
High |
Evasion technique |
| Multiple redirects |
Medium |
Chain obfuscation |
| Data URI scheme |
High |
Inline content, hard to trace |
references/workflows.md (verbatim)
Workflows: Analyzing Malicious URLs with URLScan
Workflow 1: URL Triage Pipeline
Suspicious URL received (from user report / email gateway / SIEM)
|
v
[Step 1: Defang and document URL]
+-- Replace http with hxxp, . with [.]
+-- Record original context (email subject, sender, timestamp)
|
v
[Step 2: Submit to URLScan (private visibility)]
+-- POST to /api/v1/scan/
+-- Wait for scan completion (poll /api/v1/result/{uuid}/)
|
v
[Step 3: Analyze results]
+-- Review screenshot for brand impersonation
+-- Check redirect chain (original URL vs final URL)
+-- Examine DOM for login forms / credential inputs
+-- Review network requests for suspicious endpoints
+-- Check SSL certificate details
|
v
[Step 4: Classify]
+-- Phishing (credential harvesting)
+-- Malware delivery
+-- Scam / fraud
+-- Benign (false positive)
|
v
[Step 5: Action]
+-- If malicious: Extract IOCs, block domain/IP, update filters
+-- If benign: Document and close
+-- If uncertain: Escalate for deeper analysis
Workflow 2: Bulk URL Analysis
URL list from email gateway / threat feed
|
v
[Batch submit to URLScan API]
+-- Rate limit: 2 submissions/second (free tier)
+-- Use private visibility for sensitive URLs
|
v
[Collect all results]
+-- Poll each scan UUID for completion
+-- Download screenshots and DOM content
|
v
[Automated triage]
+-- Flag: credential input forms detected
+-- Flag: brand impersonation in screenshot
+-- Flag: known phishing infrastructure (IP/ASN)
+-- Flag: newly registered domains
|
v
[Generate report]
+-- Categorized URL list (malicious / suspicious / clean)
+-- IOC extract for blocking
+-- Statistics summary
Workflow 3: IOC Extraction and Enrichment
URLScan result available
|
v
[Extract from scan]
+-- All domains contacted
+-- All IPs contacted
+-- SSL certificate fingerprints
+-- JavaScript file hashes
+-- Page resource hashes
+-- Final redirect URL
|
v
[Cross-reference]
+-- VirusTotal: domain/IP/hash reputation
+-- PhishTank: known phishing URL database
+-- WHOIS: domain registration details
+-- AbuseIPDB: IP abuse reports
+-- Google Safe Browsing: malware/phishing flags
|
v
[Compile IOC package]
+-- STIX/TAXII format for TIP
+-- CSV for firewall/proxy rules
+-- JSON for SIEM enrichment
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