How Simple RECON Earned Me ₹XX,000 at Zerodha
作者通过Shodan搜索发现Zerodha的一个子域名未受Cloudflare保护,导致原IP暴露。该漏洞使攻击者可绕过防护措施进行攻击。作者报告后获得高额赏金,展示了安全配置错误的重要性。 2025-6-6 05:5:8 Author: infosecwriteups.com(查看原文) 阅读量:10 收藏

Swarnim Bandekar

Security bugs aren’t always flashy. Sometimes, you don’t need to pop a shell or find an RCE to make an impact.
Sometimes… all you need is a little curiosity and a lot of recon.

This is how I stumbled upon an exposed origin IP at Zerodha, India’s largest stock brokerage, and how that led to an unexpected ₹XX,000 bounty — all without writing a single exploit.

Like most bug bounty hunters, I was doing my usual late-night stroll across a domain — Zerodha’s public-facing assets.
WAF? Cloudflare.
Endpoints? Mostly locked.
But I had a hunch.

Out came Shodan, my favorite search engine for all the things you shouldn’t see.

One quick dork later:

Ssl.cert.subject.CN:"domain.com" 200

And boom — I landed on an IP:
0x.0.xxx.00

An Amazon EC2 instance quietly serving traffic… and not a trace of Cloudflare in sight.

I typed in:
https://0x.0.xxx.00/login

It loaded.
No 403. No timeout. Just a clean login page staring right back at me.

I double-checked with tools: no WAF, no CDN headers, and the cert? Signed for domain.com.

Bingo.

Here’s where it got interesting. Zerodha uses Cloudflare for protection — rate limiting, WAF, DDoS, the works.
But this subdomain — sub.domain.com — wasn’t behind it.

At first glance, that might seem like a non-issue. Maybe internal, maybe forgotten.

But to an attacker?
It’s an open door.
Direct origin access means you can:

  • Bypass rate limits
  • Fuzz without detection
  • Brute force at full throttle
  • Even launch DDoS attacks — because there’s no shield in place

And it all stems from one thing: security misconfiguration.

I reported it privately through ComOlho, their bug bounty platform.
Soon after, Zerodha got back:

“Hey Swarnim, we discussed this internally… it’s not behind Cloudflare for some internal reasons. But because of your report, we’re now discussing whether to fix it. Please repost publicly — we’ll process your bounty.”

I wasn’t expecting a big payout — just happy they took it seriously.

But then…

₹XX,000 dropped into my account.

No exploit. No shell. Just impact.

  • Bug bounties aren’t about breaking things — they’re about finding things that are broken.
  • Even “boring” bugs matter — origin IP exposure can change the threat model completely.
  • If it feels too quiet… dig deeper — sometimes the loudest vulnerabilities whisper.

Don’t chase just the CVEs.
Don’t underestimate the power of recon, curiosity, and context.

This was one IP. One misconfiguration.
And it paid off — literally and figuratively.

Thanks, Zerodha. And shoutout to platforms like ComOlho for making security collaborative and rewarding.

Time to go hunting again. 🔍💻

Connect with me on LinkedIn | GitHub | Portfolio
If you liked this story, give it a 👏 and share it with fellow hackers.

Stay safe. Stay curious.
Swarnim Bandekar


文章来源: https://infosecwriteups.com/how-simple-recon-earned-me-xx-000-at-zerodha-3172aea39c3e?source=rss----7b722bfd1b8d--bug_bounty
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