Hey there!😁

At 2 AM, normal people are asleep. Developers are "just pushing one small fix" to production. And I'm sitting there with cold coffee, scrolling through a forum that looks like it hasn't been redesigned since 2006.

This is my nightlife.

And honestly? Some of my highest-severity bugs didn't start with Burp. They started with gossip.

🌑 The Truth About Dark Web Recon

Let me say this clearly: the dark web is not some Hollywood hacker basement.

It's chaotic. Half the posts are scams. The other half are ego contests. But hidden between "selling RDP access cheap" and "who has logs for X company?" — there's intelligence.

Real intelligence.

Attackers talk. Not because they want to teach. Because they want to flex.

And when they flex, they leak patterns.

🔥 The 2:13 AM Post

One random night, I saw a thread mentioning a fintech company that happened to be in scope for a bug bounty program.

The post was short:

"Their CDN caching private API responses lol."

No PoC. No explanation. Just arrogance.

Most people would ignore that.

I didn't.

Because attackers rarely describe the bug correctly — but they usually describe the symptom.

And "CDN caching private API responses" is not a beginner mistake.

🧠 Step 1: OSINT Before Touching the Target

Before sending a single request to the application, I pivoted.

I checked:

• Recent breach disclosures
• Credential dump samples floating in underground markets
• Leaked employee emails
• Subdomain references inside old JavaScript files
• Historical DNS records
• Wayback snapshots of staging endpoints

Recent breach patterns like those seen after the MOVEit exploitation wave showed how quickly attackers pivot from one SaaS misconfiguration to similar targets.

And after credential abuse incidents involving Snowflake, attackers became extremely focused on API endpoints and token reuse.

That context matters.

Because vulnerabilities don't exist in isolation. They follow trends.

🛰️ Step 2: Infrastructure Mapping

From recon, I identified:

• api.target.com
• gateway.target.com
• assets.targetcdn.com

Headers revealed Cloudflare in front.

Most endpoints returned:

cf-cache-status: DYNAMIC

Which is expected for authenticated APIs.

But one endpoint caught my attention:

GET /v2/account/summary

The response headers:

Cache-Control: public, max-age=600
X-Cache: HIT

Public?

On an account endpoint?

That's not a parameter issue. That's architectural.

🧪 Step 3: Testing Cache Key Behavior (The Right Way)

I didn't waste time adding ?test=1.

Instead, I tested how the CDN built its cache key.

Static Suffix Confusion

GET /v2/account/summary/profile.css

The response came back:

200 OK
Content-Type: application/json
Cache-Control: public, max-age=600
X-Cache: MISS

That was strange.

The CDN interpreted /profile.css as a static file. But the backend ignored the suffix and served JSON.

That mismatch is where bugs live.

💣 Step 4: Authenticated Cache Priming

Now I logged in as my test account.

GET /v2/account/summary/profile.css
Cookie: session=VALID_SESSION

Response body:

{
  "user_id": "48291",
  "email": "victim@company.com",
  "kyc_status": "verified",
  "wallet_balance": 14892.77,
  "api_token": "sk_live_xxx"
}

Response headers:

Cache-Control: public, max-age=600
X-Cache: MISS

Refresh.

X-Cache: HIT

Now the important test.

Remove the cookie.

Replay the request.

Same endpoint.

Same path.

No authentication.

And I received the same JSON response.

Publicly cached.

🧨 Why This Was Serious

This wasn't just user email leakage.

The response included:

• Live API token
• Internal user ID
• Financial balance
• KYC verification state

That API token worked against other internal endpoints.

From there, the impact expanded to:

• Token reuse abuse
• Accessing transaction history
• Pulling additional sensitive data
• Potential account takeover

This escalated quickly from "misconfigured cache header" to high-severity sensitive data exposure.

And it all started because someone at 2 AM wanted to brag.

🌚 Why Underground Chatter Matters

Dark web monitoring isn't about copying exploits.

It's about pattern recognition.

When attackers complain about:

• "CDN acting weird"
• "Private API cached"
• "GraphQL open in prod"
• "S3 bucket misconfig"

They are indirectly telling you where companies are making systemic mistakes.

And systemic mistakes are where high-impact bugs hide.

🛠️ Practical Techniques You Should Actually Use

Here's what I genuinely do now as part of my workflow:

1️⃣ Monitor Mentions of In-Scope Companies

Not for "buy access" posts.

But for:

• Infrastructure complaints
• CDN behavior discussions
• Credential reuse chatter

2️⃣ Test Path Confusion

Try:

/endpoint.css
/endpoint.json
/endpoint/anything.js
/endpoint%2ejson

Watch how CDN and backend interpret them differently.

3️⃣ Compare Authenticated vs Unauthenticated Cache Behavior

1. Send authenticated request
2. Confirm cache storage
3. Remove session
4. Replay

If the response persists — that's real impact.

4️⃣ Read Headers Like a Forensic Analyst

Look carefully at:

Cache-Control
s-maxage
Vary
X-Cache
Age

The vulnerability is often in one misused directive.

📰 What I'm Seeing Lately in Underground Spaces

Recent chatter revolves around:

• Session replay tokens leaking via CDNs
• Misconfigured GraphQL introspection
• API key exposure in cached JS files
• Log marketplaces selling fresh SaaS credentials

After large-scale incidents in the SaaS ecosystem, attackers now hunt horizontally. They look for one misconfiguration that affects thousands of users at once.

Cache bugs are perfect for that.

🏁 Final Thoughts

Bug bounty is not just about sending more requests.

It's about thinking like someone who already broke in.

Some of my best findings didn't start with a scanner. They started with curiosity.

At 2 AM, while most people are sleeping, someone is complaining on a forum about a broken CDN.

And if you're paying attention, that complaint might just turn into your next high-severity report.

Stay curious. Stay patient. And maybe… keep some coffee ready. ☕

Connect with Me!

• Instagram: @rev_shinchan
• Gmail: rev30102001@gmail.com

#EnnamPolVazhlkai😇

#BugBounty, #CyberSecurity, #InfoSec, #Hacking, #WebSecurity, #CTF