Proactive Vulnerability Management with Nuclei-Templates

projectdiscovery/nuclei-templates

From a software engineer's perspective, this project is an invaluable tool for several reasons

Proactive Vulnerability Scanning
You can integrate nuclei and its templates into your Continuous Integration/Continuous Deployment (CI/CD) pipeline. This allows you to automatically scan your code and deployed applications for known vulnerabilities before they reach production.

Security Debt Management
Regularly running nuclei scans against your applications helps you identify and track security issues, which is crucial for managing your security debt.

Knowledge Transfer
The templates themselves serve as a great learning resource. By examining them, you can gain a deeper understanding of how specific vulnerabilities, like Cross-Site Scripting (XSS) or Server-Side Request Forgery (SSRF), are exploited and detected.

Threat Intelligence
The community continuously updates the templates to cover newly discovered vulnerabilities (CVEs), zero-day exploits, and common misconfigurations. This keeps your security scanning up-to-date with the latest threats.

To start using nuclei-templates, you first need to install the nuclei engine.

The easiest way to install nuclei is to use the go programming language. If you have Go installed, run this command

go install -v github.com/projectdiscovery/nuclei/v3/cmd/nuclei@latest

Alternatively, you can download pre-compiled binaries for your operating system from the ProjectDiscovery GitHub Releases page.

Once nuclei is installed, you can perform a basic scan. The nuclei tool automatically downloads and updates the nuclei-templates repository for you.

To scan a single target, simply specify the URL

nuclei -target https://example.com

To scan a list of targets from a file, use the -list flag

nuclei -list targets.txt

Let's say you want to scan for accidentally exposed .git folders, which could leak your application's source code. The nuclei-templates repository has a template for this.

You can explore the templates by cloning the nuclei-templates repository directly

git clone https://github.com/projectdiscovery/nuclei-templates.git

Inside the cloned directory, you'll find templates organized by category. The template for .git exposure is typically found under exposures/git-exposed.yaml.

You can run nuclei with this specific template using the -t flag

nuclei -target https://my-awesome-app.com -t exposures/git-exposed.yaml

If nuclei finds a vulnerable .git folder on your target, it will output the results, helping you to quickly fix the issue.

To see what a template looks like, here's a simplified example. This YAML file checks for the presence of the robots.txt file, which is a very basic "fingerprint" of a website.

id: robots-txt-file

info:
  name: robots.txt file
  author: ProjectDiscovery
  severity: info
  description: Checks for the presence of a robots.txt file.

http:
  - method: GET
    path:
      - "{{BaseURL}}/robots.txt"

    matchers:
      - type: status
        status:
          - 200

id and info
These fields provide a unique ID and a human-readable description for the template.

http
This section defines the HTTP request to be sent.

path
Specifies the endpoint to check, using {{BaseURL}} as a placeholder for the target URL.

matchers
This is where nuclei determines if the scan was successful. In this case, it checks if the server responds with a 200 OK status code.