exploiting-broken-link-hijacking

name	exploiting-broken-link-hijacking
description	Discover and exploit broken link hijacking vulnerabilities by identifying references to expired domains, decommissioned cloud resources, and dead external services that can be claimed by an attacker.
domain	cybersecurity
subdomain	web-application-security
tags	["broken-link-hijacking","blh","subdomain-takeover","dead-link","expired-domain","supply-chain","external-resource"]
version	1.0
author	mahipal
license	Apache-2.0
nist_csf	["PR.PS-01","ID.RA-01","PR.DS-10","DE.CM-01"]
mitre_attack	["T1190","T1059.007","T1505.003","T1083","T1195"]
source	https://github.com/mukul975/Anthropic-Cybersecurity-Skills
source_commit	04450304b12645cb2b974ab96d28c0664758a88d

Exploiting Broken Link Hijacking

When to Use

• When auditing web applications for references to expired or unclaimed external resources
• During supply chain security assessments of third-party script and resource dependencies
• When testing for subdomain takeover opportunities via dangling CNAME records
• During bug bounty hunting for broken link hijacking vulnerabilities
• When assessing the security of external resource dependencies in production applications

Prerequisites

• Web crawler or spider for discovering all external links (Burp Suite Spider, Scrapy)
• DNS lookup tools for checking CNAME records and domain availability
• Domain registrar access for claiming expired domains (as proof of concept)
• Understanding of CDN and cloud service provisioning (S3, Azure Blob, GitHub Pages)
• blc (broken-link-checker) or similar tool for automated link validation
• Knowledge of services vulnerable to subdomain takeover (can-i-take-over-xyz)

Legal Notice: This skill is for authorized security testing and educational purposes only. Unauthorized use against systems you do not own or have written permission to test is illegal and may violate computer fraud laws.

Workflow

Step 1 — Crawl and Extract All External References

# Use broken-link-checker to find dead links
npx broken-link-checker http://target.com --recursive --ordered \
  --exclude-internal --filter-level 3 -o broken_links.txt

# Extract all external links from page source
curl -s http://target.com | grep -oP 'https?://[^"'"'"'\s>]+' | sort -u > all_links.txt

# Extract JavaScript sources
curl -s http://target.com | grep -oP 'src="[^"]*"' | grep -v target.com > external_scripts.txt

# Extract CSS references
curl -s http://target.com | grep -oP 'href="[^"]*\.css"' | grep -v target.com > external_css.txt

# Use wayback machine for historical external references
curl -s "https://web.archive.org/web/timemap/link/http://target.com" | \
  grep -oP 'https?://[^>]+' | sort -u > historical_links.txt

# Spider with Burp Suite