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Bug Hunting Methodology

Passive Recon

# https://github.com/glennzw/shodan-hq-nse
nmap --script shodan-hq.nse --script-args 'apikey=<yourShodanAPIKey>,target=<hackme>'

python3 favUp.py --favicon-file favicon.ico -sc
python3 favUp.py --favicon-url https://domain.behind.cloudflare/assets/favicon.ico -sc
python3 favUp.py --web domain.behind.cloudflare -s

urlhunter --keywords keywords.txt --date 2020-11-20

# Look for JS files, old links
curl -sX GET "http://web.archive.org/cdx/search/cdx?url=<targetDomain.com>&output=text&fl=original&collapse=urlkey&matchType=prefix"

python theHarvester.py -b all -d domain.com

gitrob analyze johndoe --site=https://github.acme.com --endpoint=https://github.acme.com/api/v3 --access-tokens=token1,token2

site: *.example.com -www
intext:"dhcpd.conf" "index of"
intitle:"SSL Network Extender Login" -checkpoint.com
  • Enumerate subdomains using HackerTarget
curl --silent 'https://api.hackertarget.com/hostsearch/?q=targetdomain.com' | grep -o '\w.*targetdomain.com'
  • Enumerate endpoints using CommonCrawl
echo "targetdomain.com" | xargs -I domain curl -s "http://index.commoncrawl.org/CC-MAIN-2018-22-index?url=*.targetdomain.com&output=json" | jq -r .url | sort -u

Active Recon

Network Discovery

host -t ns domain.local
domain.local name server master.domain.local.

host master.domain.local        
master.domain.local has address 192.168.1.1

dig axfr domain.local @192.168.1.1

Web Discovery

Common Files

  • security.txt: A file that provides contact info for reporting security issues with your site (like an email or PGP key).
Contact: mailto:security@example.com
  • sitemap.xml: Lists all the important URLs of your site so search engines can index them efficiently.
<urlset>
  <url><loc>https://example.com/</loc></url>
  <url><loc>https://example.com/about</loc></url>
</urlset>
  • robots.txt: Tells search engine crawlers which pages or files they can or cannot access on your site.
User-agent: *
Disallow: /admin/

Enumerate Files and Folders

Enumerate all accessible files and subdirectories. Once the underlying technology has been identified, prioritize the use of targeted wordlists rather than generic ones. Technology specific wordlists such as those provided by Assetnote (https://wordlists.assetnote.io), significantly improve coverage and efficiency. Examples include httparchive_parameters_top_1m_2026_01_27.txt, httparchive_directories_1m_2026_01_27.txt, and httparchive_php_2026_01_27.txt.

ffuf -H 'User-Agent: Mozilla' -v -t 30 -w mydirfilelist.txt -b 'NAME1=VALUE1; NAME2=VALUE2' -u 'https://example.com/FUZZ'
gobuster dir -a 'Mozilla' -e -k -l -t 30 -w mydirfilelist.txt -c 'NAME1=VALUE1; NAME2=VALUE2' -u 'https://example.com/'

Identify and enumerate backup and temporary files that may have been unintentionally exposed. These files often contain source code, credentials, or sensitive configuration data and are commonly created by editors, deployment processes, or manual backups.

bfac --url http://example.com/test.php --level 4
bfac --list testing_list.txt

Crawl the website's pages and resources to identify additional attack surface and expand the assessment perimeter.

katana -u https://tesla.com
echo https://google.com | hakrawler

Next.js Endpoints

In Next.js, window.__BUILD_MANIFEST is a runtime global variable that the framework automatically injects into the client-side JavaScript bundle.

Go to DevTools->Console and execute this JavaScript code:

console.log(window.__BUILD_MANIFEST)
console.log(__BUILD_MANIFEST.sortedPages)

If you inspect your app in the browser console (for a production build), you might see something like this:

{__rewrites: {…}, /: Array(10), /404: Array(8), /500: Array(4), /_error: Array(1), …}
/: (10) ['static/chunks/2852872c-b605aca0298c2109.js', 'static/chunks/3748-2a8cf394c7270ee0.js']
/404: (8) ['static/chunks/2852872c-b605aca0298c2109.js', 'static/chunks/3748-2a8cf394c7270ee0.js']
/500: (4) ['static/chunks/3748-2a8cf394c7270ee0.js', 'static/chunks/1221-b44c330d41258365.js']
/[slug]: (30) ['static/chunks/2852872c-b605aca0298c2109.js', 'static/chunks/29107295-4cc022cea922dbb4.js']
/_error: ['static/chunks/pages/_error-6ddff449d199572c.js']
/about/[slug]: (31) ['static/chunks/2852872c-b605aca0298c2109.js']

JS and HTML Comments

Retrieve comments in source code.

<!-- HTML Comment -->
// JS Comment

Internet Archive

Identify historical URLs and endpoints by reviewing archived content from sources such as the Wayback Machine and the Internet Archive.

gau --o example-urls.txt example.com
gau --blacklist png,jpg,gif example.com

Hidden Parameters

Search for hidden parameters:

x8 -u "https://example.com/?something=1" -w <wordlist>

Map Technologies

echo www.hackerone.com | cdncheck -resp
www.hackerone.com [waf] [cloudflare]

Manual Testing

Explore the website with a proxy:

Automated vulnerability scanners

nuclei -u https://example.com

./nikto.pl -h http://www.example.com

Looking for Web Vulnerabilities

  • Explore the website and look for vulnerabilities listed in this repository: SQL injection, XSS, CRLF, Cookies, ....
  • Test for Business Logic weaknesses
    • High or negative numerical values
    • Try all the features and click all the buttons

  • The Web Application Hacker's Handbook Checklist

  • Subscribe to the site and pay for the additional functionality to test

  • Inspect Payment functionality - @gwendallecoguic

    If the webapp you're testing uses an external payment gateway, check the doc to find the test credit numbers, purchase something and if the webapp didn't disable the test mode, it will be free

From https://stripe.com/docs/testing : "Use any of the following test card numbers, a valid expiration date in the future, and any random CVC number, to create a successful payment. Each test card's billing country is set to U.S."

Test card numbers and tokens

NUMBER BRAND TOKEN
4242424242424242 Visa tok_visa
4000056655665556 Visa (debit) tok_visa_debit
5555555555554444 Mastercard tok_mastercard

International test card numbers and tokens

NUMBER TOKEN COUNTRY BRAND
4000000400000008 tok_at Austria (AT) Visa
4000000560000004 tok_be Belgium (BE) Visa
4000002080000001 tok_dk Denmark (DK) Visa
4000002460000001 tok_fi Finland (FI) Visa
4000002500000003 tok_fr France (FR) Visa

References