CeWL (Custom Word List generator) is a versatile open-source tool written in Ruby that’s indispensable for penetration testers. It crawls a target website to extract unique words and phrases, helping you create tailor-made dictionaries for password cracking or brute-force attacks. In this post, we explore what CeWL is, its standout features, and how you can integrate it into your testing workflow.

What is CeWL?

CeWL is designed to build custom wordlists by crawling web pages and harvesting content. Instead of relying on generic dictionaries, CeWL allows you to capture words that are contextually relevant to your target. This custom approach can significantly improve your success rate when targeting passwords derived from a website’s unique content.

Key Features

• Deep Crawling: Recursively scans web pages to gather words from visible text, meta tags, and other elements.
• Customizable Parameters: Set options such as recursion depth, minimum word length, and output file location to fine-tune your wordlist.
• Efficient Filtering: Automatically removes duplicates and irrelevant content, resulting in a focused dictionary for your tests.
• Integration Ready: Easily combine CeWL with other security tools like password crackers and brute-force utilities to enhance your overall testing workflow.

Using CeWL in Your Workflow

Integrating CeWL into your penetration testing process is straightforward. Here’s an example command to get you started:

cewl https://target-website.com -w target_wordlist.txt -d 2 -m 5

This command instructs CeWL to:

• Crawl https://target-website.com with a recursion depth of 2.
• Capture words with a minimum length of 5 characters.
• Save the output to target_wordlist.txt.

Best Practices

• Fine-Tune Parameters: Adjust recursion depth and minimum word length to match the complexity and content of the target site.
• Complement Existing Dictionaries: Use CeWL-generated lists to enhance and customize traditional wordlists.
• Use Ethically: Always ensure you have explicit authorization to scan and test a target website.
• Automate When Possible: Incorporate CeWL into your reconnaissance pipelines for automated, regular wordlist generation.

Advanced Usage and Tips

Beyond basic word extraction, CeWL offers options to harvest email addresses and additional metadata, which can provide further insights during engagements. For a full list of capabilities and advanced parameters, check out the CeWL GitHub repository.

Final Thoughts

CeWL stands out as a powerful tool for creating custom wordlists tailored to the unique characteristics of your target. By leveraging its deep crawling and customization features, you can significantly enhance your penetration testing efforts. Whether you’re a seasoned professional or a budding pentester, incorporating CeWL into your toolkit is a smart move—just remember to use it responsibly and with the proper permissions.