The $500 Vulnerability: How Censys Search Led Me to a Quick Bug Bounty

Reconnaissance is the backbone of ethical hacking and bug bounty hunting — skip it, and you’re waving goodbye to easy payouts. Tools like Censys Search, Shodan, Nmap, and Burp Suite are the ultimate weapons for uncovering security vulnerabilities, from misconfigured servers and open ports to default credentials and exposed APIs. Recon isn’t just important — it’s how cybersecurity experts uncover zero-day vulnerabilities, authentication bypass flaws, and data exposure issues that organizations didn’t even know they had. Think of recon as your penetration testing prep — it’s where you find the breadcrumbs that lead to the treasure chest. Without it, you’re like a hacker at a buffet with no plate: overwhelmed, underprepared, and probably missing out on the good stuff. So, embrace the power of recon, master tools like Wireshark and Metasploit, and turn those overlooked vulnerabilities into your next big bug bounty payday.

I was diving into a bug bounty program where every asset was in scope — music to any hacker’s ears! As part of my reconnaissance, I used Censys Search to perform a live subdomain enumeration, leveraging my guide Live Subdomain Enumeration Using Censys. By searching for TLS certificate leaf data with the query :-

I quickly uncovered subdomains tied to the target asset. Then, curiosity got the better of me, and I decided to look for .dev domains linked to the same organization with the query :-

To my surprise, I found that these .dev domains also belonged to the target organization, revealing potential hidden development environments — a jackpot for penetration testers and ethical hackers hunting for security vulnerabilities.

Then, a light bulb went off — what if I crafted a Censys query to filter out results containing the keywords ‘login’ and ‘password’? This way, I could focus on IPs and subdomains without these common terms in their responses. My query looked like this:-

This clever trick narrowed down the results to just 10 entries. Skipping the tedious manual review, I uncovered one IP belonging to the target organization that exposed an unauthenticated dashboard. While the data on the dashboard wasn’t highly sensitive, it was still a security misconfiguration that earned me a $500 bug bounty reward. This highlights the power of customized queries in tools like Censys for discovering exposed assets and identifying vulnerabilities.

That’s all for today, folks! Keep hunting, keep learning, and remember — every small discovery counts in the world of bug bounty hunting. Bye-bye and happy hacking!