Robots.txt

robots.txt is a text file webmasters create to instruct web robots (typically [[Search Engine Crawlers]]) how to crawl and index pages on their website. It is part of the [[Robots Exclusion Protocol (REP)]], a group of web standards that regulate how robots crawl the web, access and index content, and serve that content up to users.

The file is placed in the root directory of the website (e.g., http://example.com/robots.txt). It contains directives for user agents (crawlers), specifying which parts of the site should or should not be crawled. Common directives include "[[User-agent]]" (the type of crawler the rule applies to), "Disallow" (paths that should not be crawled), and "Allow" (paths that can be crawled, typically used to override a Disallow rule).

robots.txt can be a valuable resource during the reconnaissance phase of a penetration test. It can reveal the structure of a website and expose hidden or sensitive directories and files that are not intended for public viewing but are not properly secured.

The file might list directories the web administrator wants to keep away from crawlers. These could include admin panels, login pages, or directories containing sensitive data, which could be potential targets for further investigation.

It helps in understanding the application's structure, which is crucial for a comprehensive penetration test. It might reveal areas of the site that are less likely to be exposed to regular traffic and potentially less secure.

While robots.txt can provide useful information, it's important to note that not all webmasters accurately or thoroughly document the structure of their site in this file. Some might intentionally put misleading information in robots.txt.

robots.txt is a request, not an enforcement. Malicious bots are not likely to honor this file, so sensitive directories and files listed in robots.txt should also be protected through proper security measures.

If sensitive paths are listed in robots.txt, it could inadvertently act as a guide for malicious actors. Therefore, it's a best practice not to rely on robots.txt to protect sensitive areas of a website.