js-files-and-signup

JavaScript files are often rich in hidden endpoints, tokens, API calls, and logic. During recon, they can reveal:

• Hidden API endpoints

• Functionality not exposed in the UI

• Secrets (rare but possible: API keys, tokens)

• Third-party service usage

• JS logic flaws

Tools & Commands:

# 1. Download JS files (manually or automated)
wget -r -l2 -nd -A js https://target.com

# 2. Use LinkFinder to find endpoints
python3 linkfinder.py -i target.js -o cli

# 3. Use SecretFinder to identify secrets
python3 SecretFinder.py -i target.js -o cli

# 4. Grep manually for common patterns
grep -Eo "(https?:\/\/[^\"]+|api\/[^\"]+|key|token|auth)" target.js

# 5. Use JSParser
python3 JSParser.py -u https://target.com -o js_endpoints.txt

# 6. Use `subjs` to gather JS links from a domain
subjs -i domains.txt -o jsfiles.txt

Signup Page Recon

Signup forms can be abused or misconfigured, revealing issues like:

• User Enumeration

• Invite Code Leaks

• Role Escalation

• Password Policy Weaknesses

• Rate Limiting / CAPTCHA issues

Things to Check:

1. Check for Email/Username Enumeration:

   • Different error messages for existing vs new users

   • Use tools like ffuf or Burp Intruder

2. Test for Weak Password Policy:

   • Try simple passwords: 123456, password, etc.

   • Try long input to test length limit.

3. Check Rate Limiting / CAPTCHA:

   • Use ffuf/hydra for brute force attempts

   • Check if rate limits or WAF triggers exist

4. Check for Role/Invite Bypass:

   • Try to sign up with special email patterns ([e-mail]

   • Check if changing parameters (role=admin) works in POST request

5. Tamper Signup POST Data:

   • Use Burp to intercept & modify fields

   • Look for hidden role, referral, or invite_code fields

Automated Tools & Scripts

• JSRecon.sh – Custom script to automate JS scraping and parsing

• waymore, gau, waybackurls – Pull archived JS files

gau target.com | grep '\.js' | tee jsurls.txt

Notes to Keep in Mind

• Always check JavaScript files loaded from subdomains as well.

• Check third-party integrations — sometimes dev/test keys are exposed.

• Signup page misconfigs are a gold mine for business logic issues.

• Combine with tools like Burp Suite, ffuf, and qsreplace.