Exploiting the Unseen: Mastering 0day Discovery with Nuclei Templates in Bug Bounty Hunting


Creating and using Nuclei templates for identifying potential 0day vulnerabilities requires a deep understanding of vulnerability research and the specific software or systems being targeted. It’s crucial to approach this with a strong ethical framework and always engage in responsible disclosure.

Below is a hypothetical example to illustrate the process. Remember, this is purely educational and should not be used for unauthorized testing. Always get permission before testing a target.

Example Nuclei Template for a Hypothetical 0day

Let’s say you’ve identified a potential 0day in a web application’s API where a specific endpoint is vulnerable to a SQL injection. Here’s a basic Nuclei template that might be used to detect this vulnerability:

id: potential-0day-sql-injection

  name: Potential 0day SQL Injection
  author: yourname
  severity: critical
  description: Detects a potential SQL injection vulnerability in XYZ API.
  tags: 0day,sqlinjection

  - method: POST
      - "{{BaseURL}}/vulnerable/endpoint"
    body: "parameter=susceptibleToInjection"
      - type: word
          - "SQL syntax error"
          - "ORA-00933"
        part: body

Domain Reconnaissance Script

Before running Nuclei, you would perform domain reconnaissance. Below is a simple script using the tool subfinder to find subdomains:

subfinder -d example.com -o subdomains.txt

This command will list subdomains of example.com and save them to subdomains.txt.

Running Nuclei with the Template

After conducting domain reconnaissance and obtaining a list of subdomains, you would run Nuclei with your custom template:

nuclei -l subdomains.txt -t potential-0day-sql-injection.yaml -o results.txt

This command tells Nuclei to test each subdomain listed in subdomains.txt with your potential-0day-sql-injection template and output the results to results.txt.

Hypothetical Result

Imagine you find that api.subdomain.example.com is vulnerable:

[2023-12-25] [critical] api.subdomain.example.com Potential 0day SQL Injection

Next Steps

If you legitimately discover a vulnerability:

  1. Verify and Document: Make sure the finding is accurate and document all relevant details.
  2. Responsible Disclosure: Contact the company owning the domain, preferably through their vulnerability disclosure program, and provide them with your findings.
  3. Do Not Disclose Publicly: Until the company has had a chance to fix the issue and has agreed to disclosure.


This example is purely illustrative. Real-world 0day hunting requires extensive knowledge and should always be conducted ethically and legally. Always seek permission and adhere to legal and ethical guidelines in cybersecurity research.

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