What common attack can be identified by accessing a URL with '../' sequences in it?

The correct answer is a directory traversal attack. This type of attack involves manipulating the URL or file paths to navigate the server's file system beyond the web application's root directory. By using sequences like '../', an attacker can attempt to access files and directories that are outside the intended scope of the web server, potentially allowing access to sensitive information, configuration files, or system files.

In a directory traversal attack, the '../' sequences are specifically used to move up the directory structure. Web applications that do not properly validate or sanitize input can be vulnerable to such attacks, making it possible for an attacker to exploit this flaw to gain unauthorized access to restricted files.

In contrast, SQL injection attacks target database entries through malicious SQL code embedded in input fields, and cross-site scripting (XSS) attacks involve injecting malicious scripts into webpages viewed by users. Phishing attacks focus on deceiving users into providing sensitive information, typically through fraudulent websites or emails. Each of these attacks operates on different principles and attack vectors than directory traversal.