What is analyzing-malicious-url-with-urlscan?

A guide to using URLScan.io, a service that opens suspicious web addresses in an isolated browser and records what they do. It captures page screenshots, HTML, network requests, and JavaScript activity.

Use it to investigate phishing and credential-stealing pages, inspect redirects, review page content, and automate URL checks through the service's API.

It lets investigators examine phishing pages and malicious redirects without loading them directly on their own computer. The recorded evidence makes suspicious web behaviour easier to review.

analyzing-malicious-url-with-urlscan — Skill for Claude Code by plurig

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent

npx skills add plurigrid/asi --skill analyzing-malicious-url-with-urlscan

Clone the repo

git clone --depth 1 https://github.com/plurigrid/asi

Made for: Claude Code.

Or install asi, the plugin that ships this one along with the rest of its 56 skills.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/plurigrid/asi/analyzing-malicious-url-with-urlscan/github.svg)](https://agentmods.dev/skills/plurigrid/asi/analyzing-malicious-url-with-urlscan)

Your own site

<a href="https://agentmods.dev/skills/plurigrid/asi/analyzing-malicious-url-with-urlscan"><img src="https://agentmods.dev/badge/skills/plurigrid/asi/analyzing-malicious-url-with-urlscan/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/plurigrid/asi/analyzing-malicious-url-with-urlscan"><img src="https://agentmods.dev/badge/skills/plurigrid/asi/analyzing-malicious-url-with-urlscan.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 48 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 884 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin 95% copy Near-identical to another mod in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.00048	$0.00884
Opus 5	$0.00024	$0.00442
Sonnet 5	$0.00010	$0.00177
Haiku 4.5	$0.00005	$0.00088

Measured 7d ago against content hash 6a0d047f1987, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

analyzing-malicious-url-with-urlscan scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 7d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

This is a copy

95% identical to analyzing-malicious-url-with-urlscan — 26 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

plugins/asi/skills/analyzing-malicious-url-with-urlscan/SKILL.md · 93 lines

How it starts

The opening of the file, as written. The whole thing — 93 lines — stays where its author put it; the contents beside it link to each section on GitHub.

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-api-key
     Body: {"url": "https://suspicious-url.com", "visibility": "private"}

Read the full file on GitHub · 93 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

7d ago First seen · 93 lines · 48 tokens per session scan A 6a0d047f1987

Subscribe to this mod's changes

analyzing-malicious-url-with-urlscan is a skill published in the GitHub repository plurigrid/asi (62 stars, last pushed 2mo ago), licensed MIT. It adds 48 tokens to every session and 884 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. It is 95% identical to analyzing-malicious-url-with-urlscan, differing in 26 lines, and is treated as a copy.

Browser automation Security awareness dmarc email-security phishing social-engineering threat-intelligence url-analysis

analyzing-malicious-url-with-urlscan

Getting it into your agent

Wrote this? Show the measurements

What it costs to keep this loaded

Grade A, and why

Nothing flagged

This is a copy

How it starts

Analyzing Malicious URL with URLScan

Overview

When to Use

Prerequisites

Key Concepts

URLScan Capabilities

Phishing URL Red Flags

Workflow

Step 1: Submit URL to URLScan

What this file has done since we first saw it

Other skills, from other repositories

analyzing-malicious-url-with-urlscan

analyzing-malicious-url-with-urlscan

analyzing-malicious-url-with-urlscan

analyzing-malicious-url-with-urlscan

analyzing-malicious-url-with-urlscan

analyzing-malicious-url-with-urlscan