Hey there!😁
The other day I realized something: Hackers are like people standing in a buffet line… loudly discussing which dish tastes bad. Most people are busy eating. A few smart ones are listening to the complaints.
That's how I found one of my favorite bugs.
Watching the Hunters Before Hunting 🕵️♂️
Most bug bounty write-ups start like this:
"I opened the target, ran recon, found a bug."
Mine started differently.
I wasn't looking at the target first. I was watching attackers.
If you spend enough time in public threat-intel feeds, breach forums, and security research channels, you start noticing patterns:
- What techniques attackers are discussing
- Which misconfigurations are trending
- Which frameworks are being targeted that month
- Which headers, CDNs, and caching layers are failing in the wild
That week, one topic kept popping up everywhere:
Cache key confusion in modern CDNs.
Not the old-school tricks. Newer edge-layer behaviors.
That caught my attention.
The Darkweb Signal That Started It 📡
One night while reviewing breach discussions and OSINT feeds, I noticed chatter about:
- Exposed internal APIs cached unintentionally
- Cache poisoning through uncommon request variations
- Sensitive JSON responses being cached at edge nodes
Around the same time, several public reports and news articles were discussing major incidents where:
- Configuration files were indexed by search engines
- API responses were cached publicly
- Debug endpoints leaked environment data
Nothing groundbreaking individually. But together? A pattern.
And patterns are where bugs live.
Phase 1 — Mass Recon (The Quiet Grind) 🔍
I started wide.
Typical recon stack:
- Subdomain enumeration
- Historical URL collection
- Endpoint discovery
- Response fingerprinting
But this time I added something different:
Cache behavior mapping
Instead of just asking:
"Does this endpoint exist?"
I asked:
"Does this endpoint behave differently under variation?"
That's a powerful shift in mindset.
Phase 2 — Finding Something Interesting
Eventually I found an endpoint that:
- Returned structured JSON
- Contained metadata fields
- Responded slightly differently based on request context
More interestingly:
- Response headers suggested caching
- The cache control policy wasn't strict
- The response varied under specific request conditions
That combination is always worth investigating.
Phase 3 — Studying the Cache Behavior 🧠
Before touching payloads, I mapped behavior:
Things worth testing in cache research:
- Header influence
- Protocol variations
- Content negotiation behavior
- Host or origin interpretation
- Edge node normalization
I wasn't trying to break anything yet.
I was trying to understand how the system thought.
That's the real skill in bug bounty.
Phase 4 — The Breakthrough Moment ⚡
While observing responses, I noticed something subtle:
The backend generated dynamic content. But the edge layer didn't always treat requests uniquely.
That's the danger zone.
A dynamic response + weak cache key logic = potential sensitive exposure.
Phase 5 — Proof of Concept (Safely and Responsibly)
To confirm the behavior, I performed controlled testing:
- Request variation
- Response comparison
- Cache hit analysis
What I observed:
- A response generated in one context was served in another
- Metadata fields appeared that should not be public
- Debug identifiers were visible
No destructive testing. No aggressive payloads. Just controlled verification.
That's important.
Techniques That Help in These Scenarios 🛠️
These approaches consistently help when hunting for sensitive data exposure:
1. Response Diffing
Compare small variations in requests and study output differences.
2. Header Influence Testing
Some infrastructures still trust headers more than they should.
3. Behavior Timing
Caching layers often reveal themselves through timing patterns.
4. Content-Type and Negotiation Testing
Sometimes APIs behave differently depending on expected formats.
5. Debug Surface Discovery
Look for:
- Trace IDs
- Version banners
- Internal service names
- Environment indicators
These often lead to deeper findings.
Darkweb Trends Hunters Should Watch 👁️
If you want an edge in bug bounty, watch what attackers are discussing.
Common recurring themes lately:
- Misconfigured storage buckets
- Internal APIs exposed via mobile apps
- Cache leaks in edge platforms
- Debug endpoints left in production
Attackers follow efficiency.
Bug hunters should too.
A Lesson Most People Miss
Tools are useful. Recon is essential.
But observation is powerful.
The real advantage comes from:
Understanding what attackers are trying today.
Not last year. Not five years ago.
Today.
Final Thoughts (From One Hunter to Another)
Bug bounty isn't about:
Running more tools Sending more payloads Scanning more targets
It's about thinking differently.
Sometimes the best recon target isn't the application…
It's the attackers themselves.
Connect with Me!
- Instagram: @rev_shinchan
- Gmail: rev30102001@gmail.com