How to Use the Command 'katana' (with examples)

Katana is a powerful and fast web crawling tool designed primarily for execution within automation pipelines. Unlike traditional crawlers, Katana offers both headless and non-headless modes, supporting deep integrations with other tools and optimizing for performance in diverse environments. Whether for security testing, data gathering, or web indexing, Katana streamlines the process, ensuring efficient, thorough crawling of web resources.

Use case 1: Crawl a List of URLs

Code:

katana -list https://example.com,https://google.com,...

Motivation: Crawling a list of URLs is a foundational task in web data analysis, digital marketing, and SEO optimization. Whether performing security audits or competitive analysis, crawling multiple domains can unveil hidden insights and potential vulnerabilities.

Explanation:

• katana: The command tool used for crawling.
• -list: Specifies multiple URLs for Katana to crawl. This allows the user to include several websites in a single operation, which is useful for batch processing or comparative analysis.

Example Output: A comprehensive list of pages, scripts, and media resources associated with each provided URL, captured and displayed in a structured output format.

Use case 2: Crawl a URL Using Headless Mode with Chromium

Code:

katana -u https://example.com -headless

Motivation: Using the headless mode improves crawling performance by not rendering a full visual output. Headless browsing is efficient, making it a staple in automated testing environments and continuous integration pipelines where GUI is unnecessary.

Explanation:

• -u https://example.com: Defines the Uniform Resource Locator to be crawled.
• -headless: Enables headless browsing, using Chromium to perform tasks without opening a graphical interface, thus increasing speed and minimizing resource usage.

Example Output: A list of all resources (e.g., JavaScript files, CSS assets, links) fetched from the specified URL, all processed without loading a visible browser window.

Use case 3: Use subfinder for URL Discovery from Subdomains and Passive Sources

Code:

subfinder -list path/to/domains.txt | katana -passive

Motivation: Security professionals often need to identify every possible entry point on a domain, including subdomains. This command pipeline provides a comprehensive enumeration of URLs using both subdomain discovery and passive source aggregation, crucial for vulnerability assessment.

Explanation:

• subfinder -list path/to/domains.txt: Uses Subfinder to find subdomains from the domains listed in the specified file.
• |: Pipes the output of subfinder as input to the next command.
• -passive: Instructs Katana to utilize passive sources such as the Wayback Machine, fetching historical URLs that might not be immediately apparent.

Example Output: A detailed compilation of subdomains and URLs sourced passively, offering a broader spectrum for analysis or penetration testing.

Use case 4: Pass Requests Through a Proxy with Custom Headers

Code:

katana -proxy http://127.0.0.1:8080 -headers path/to/headers.txt -u https://example.com

Motivation: Using proxies is essential for anonymity, bypassing geo-restrictions, or inspecting traffic through a controlled environment. Adding custom headers allows for simulating various client requests, testing certain application behaviors, or modifying user-agent strings for compliance or obfuscation.

Explanation:

• -proxy http://127.0.0.1:8080: Redirects the requests through a specified proxy, useful for monitoring traffic or bypassing network restrictions.
• -headers path/to/headers.txt: Reads and applies custom headers from a file, providing flexibility in request modifications.
• -u https://example.com: States the target URL for crawling.

Example Output: A log of media, HTML, and script files requested through the specified proxy, modified by any custom headers applied, capturing server responses and transaction details.

Use case 5: Specify Crawling Strategy, Depth, and Rate Limiting

Code:

katana -strategy depth-first|breadth-first -depth value -rate-limit value -u https://example.com

Motivation: Fine-tuning the crawling strategy allows for more tailored approaches to information gathering. The depth-first search prioritizes deep exploration of a single branch, while breadth-first offers level-wise coverage. Rate limiting is critical to respect crawling politeness policies and prevent server overload.

Explanation:

• -strategy depth-first|breadth-first: Chooses between depth-first or breadth-first crawling strategy depending on the desired page hierarchy traversal.
• -depth value: Limits how deep the crawler should go in terms of subdirectory levels.
• -rate-limit value: Specifies the number of requests Katana should issue per second, controlling the crawling speed to adhere to ethical web scraping practices.
• -u https://example.com: The starting point for crawling, openly accepting any valid web page URL.

Example Output: A sequentially collected assortment of links and resources in the order determined by the specified strategy, observed at set levels of depth and controlled by request frequency constraints.

Use case 6: Find Subdomains and Crawl Each for a Limited Time

Code:

subfinder -list path/to/domains.txt | katana -crawl-duration value -output path/to/output.txt

Motivation: Time-boxed crawling is utilized to manage resources effectively and prevent excessively long operations. This approach is beneficial when prioritizing tasks with strict deadlines or when verifying behavior in a live environment during limited testing windows.

Explanation:

• subfinder -list path/to/domains.txt: Input subdomains discovered by Subfinder from the provided domains file.
• |: Directly passes the subfinder output into the katana command.
• -crawl-duration value: Caps the time allotted for crawling each URL, enhancing resource management.
• -output path/to/output.txt: Directs the crawler to store results in a designated text file, preserving findings for further analysis.

Example Output: A time-bound crawl of each subdomain with results written to a file, featuring URL endpoints, discovered links, and metadata, enabling quick turnarounds in continuous analysis settings.

Conclusion:

Katana’s versatility makes it a standout tool for automated web crawling, tailored to fit diverse scenarios from security testing to digital marketing optimization. Its ability to integrate with other utilities like Subfinder and support for advanced configurations underlines its capacity as a comprehensive solution for script-based web interactions. By following these command examples, users can effectively harness Katana’s full suite of functionalities.