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Introduction:
The bug bounty landscape is evolving, and automation is king. Nuclei, a fast and customizable vulnerability scanner, has become an indispensable tool for security researchers. This article provides a comprehensive guide to contributing Nuclei templates, a direct path to earning bounties by enhancing the security community’s arsenal.
Learning Objectives:
- Understand the structure and syntax of a Nuclei template.
- Learn how to identify and replicate vulnerabilities for template creation.
- Master the process of finding, claiming, and contributing to bounty-assigned template issues on GitHub.
You Should Know:
1. Finding Open Bounty Opportunities
The first step is locating open issues that offer financial rewards for template development.
Navigate to the project-nuclei GitHub repository issues page Use the GitHub search filter to find open bounty issues is:issue is:open label:"💎 Bounty"
This GitHub search query filters the issues list to only show open tickets that have been tagged with the “Bounty” label. Researchers must regularly monitor this list, as high-value bounties are claimed quickly. The filter ensures you are only viewing opportunities that offer financial compensation for your development efforts.
2. The Basic Structure of a Nuclei Template
Every Nuclei template is a YAML file defining the vulnerability check.
id: example-cve
info:
name: Test Vulnerability
author: your_name
severity: high
description: Description of the vulnerability.
http:
- method: GET
path:
- "{{BaseURL}}/vulnerable-endpoint"
matchers:
- type: word
words:
- "root:"
part: body
This YAML structure is the foundation of all Nuclei templates. The `id` field must be unique. The `info` section contains metadata for identification and classification. The `http` block defines the HTTP request to be made. Crucially, the `matchers` section contains the logic to determine a successful find based on the HTTP response, such as matching specific words in the response body.
3. Crafting a Simple GET Request Template
Templates often start with a straightforward GET request to detect exposed information.
id: exposed-aws-keys
info:
name: Exposed AWS Access Keys
author: researcher
severity: critical
reference: https://blog.yeswehack.com/yeswerhackers/how-to-find-exposed-aws-keys/
http:
- method: GET
path:
- "{{BaseURL}}/.env"
- "{{BaseURL}}/config.json"
matchers-condition: and
matchers:
- type: word
words:
- "AWS_ACCESS_KEY_ID"
- "AWS_SECRET_ACCESS_KEY"
condition: and
- type: status
status:
- 200
This template checks common files (.env, config.json) for the presence of AWS credential strings. The `matchers-condition: and` directive means all matchers must return true for the template to trigger a hit. It requires both the keywords to be present and the HTTP status code to be 200, reducing false positives.
4. Exploiting POST-Based Vulnerabilities
Many vulnerabilities, like SQLi, require sending data via POST.
id: sql-injection-auth-bypass
info:
name: SQL Injection Authentication Bypass
severity: high
author: researcher
http:
- method: POST
path:
- "{{BaseURL}}/login"
body: "username=admin' OR '1'='1&password=anypassword"
matchers:
- type: word
words:
- "Welcome, admin"
- "Dashboard"
condition: or
- type: status
status:
- 302
This template demonstrates testing for a classic SQL injection flaw. The `body` key contains the POST payload with the malicious SQL snippet. The matchers look for either a successful login message (Welcome, admin or Dashboard) or an HTTP 302 redirect, which is a common response after a successful login, making the check more robust.
5. Advanced Fuzzing with Race Conditions
Testing for race conditions requires sending multiple concurrent requests.
id: race-condition-coupon-claim
info:
name: Race Condition in Coupon Claim
severity: medium
author: researcher
http:
- raw:
- |
POST /api/coupon/claim HTTP/1.1
Host: {{Host}}
Content-Type: application/json
Authorization: Bearer {{token}}
{"coupon_code":"BLACKFRIDAY100"}
- |
POST /api/coupon/claim HTTP/1.1
Host: {{Host}}
Content-Type: application/json
Authorization: Bearer {{token}}
{"coupon_code":"BLACKFRIDAY100"}
attack: race
race-count: 50
matchers:
- type: word
words:
- "success"
count: 2
This advanced template uses the `raw` request mode and the `attack: race` directive. Nuclei will send the same request 50 times (race-count: 50) in parallel, attempting to claim the same coupon repeatedly. A successful hit is triggered if multiple “success” responses are found, indicating the race condition was exploited.
6. Leveraging Dynamic Variables and Payloads
Nuclei can integrate with external payload files for comprehensive testing.
Create a file `ssrf-payloads.txt` with common SSRF targets admin.local localhost 169.254.169.254 metadata.google.internal
id: ssrf-internal-network
info:
name: SSRF to Internal Network
severity: high
http:
- method: GET
path:
- "{{BaseURL}}/fetch?url=http://{{payload}}"
payloads:
payload: ssrf-payloads.txt
matchers:
- type: word
words:
- "root:"
- "AWS"
- "metadata"
This template uses an external payload file (ssrf-payloads.txt) to fuzz a parameter. For each target in the file, Nuclei will send a new request. This is efficient for testing Server-Side Request Forgery (SSRF) flaws against a list of known internal IPs or domains. The matchers then check the response for indicators of success.
7. Validating the Template Before Contribution
Before submitting a pull request, test your template rigorously.
Test a single template against a specific target nuclei -t /path/to/my-template.yaml -u https://example.com -v Run a template against a list of targets to check for false positives nuclei -t /path/to/my-template.yaml -l list-of-targets.txt -silent Validate the template's YAML syntax using the Nuclei CLI nuclei -validate -t /path/to/my-template.yaml
Testing is critical. The `-v` (verbose) flag provides detailed output for debugging. Running the template against a list of targets (-l) helps identify false positives. Finally, the `-validate` flag checks the YAML syntax for errors, ensuring your contribution is not rejected for a simple formatting mistake.
What Undercode Say:
- The Democratization of Security Research: Nuclei’s template system lowers the barrier to entry for bug bounty hunting. You don’t need to be an elite programmer; you need to understand a vulnerability and be able to replicate it in a YAML file. This empowers a wider range of researchers to contribute meaningfully and earn rewards.
- Quality Over Quantity: The most lucrative and respected bounty hunters are those who contribute high-quality, low-false-positive templates for novel or complex vulnerabilities. A single, well-crafted template for a critical, hard-to-find flaw is infinitely more valuable than a dozen templates for common low-hanging fruit.
The shift towards bounty-backed template development represents a maturation of the crowdsourced security model. It incentivizes not just the finding of bugs, but the creation of tools that automate their discovery at scale. This creates a powerful positive feedback loop: more templates lead to more bugs found, which leads to more secure software, which in turn forces researchers to develop even more sophisticated templates. The organizations funding these bounties are effectively investing in a permanent, self-improving security automation system, making it one of the most efficient allocations of cybersecurity spending.
Prediction:
The success of Nuclei’s bounty program will catalyze a broader industry trend where open-source security tools adopt similar incentivized contribution models. We will see platforms for fuzzing, SAST, and DAST tools integrate bounty markets directly into their ecosystems. This will professionalize the vulnerability research economy, creating a new class of security professionals who earn a living primarily by writing detection logic rather than manually testing individual applications, ultimately leading to a more automated and proactive cybersecurity posture globally.
🎯Let’s Practice For Free:
IT/Security Reporter URL:
Reported By: Abhirup Konwar – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
