Which type of attack involves accessing directories outside of the web root and can be mitigated by a web application firewall like ModSecurity?

The type of attack that involves accessing directories outside of the web root is known as a directory traversal attack. This method typically allows an attacker to navigate through the file system of a server by exploiting vulnerabilities in web applications. By sending specially crafted requests, an attacker can attempt to access sensitive files or directories that are not intended to be accessible via the web interface.

Using a web application firewall (WAF) like ModSecurity can help mitigate directory traversal attacks. WAFs analyze incoming traffic and can block malicious requests based on predefined rules. For instance, ModSecurity can be configured to identify patterns indicative of directory traversal attempts and prevent these requests from reaching the web application, thus safeguarding the server's file structure.

Understanding this type of attack is crucial for implementing effective security measures since accessing unauthorized directories can lead to significant data breaches or exposure of sensitive information. Properly configuring a WAF is an essential part of securing web applications against such vulnerabilities.