Cross-Site Scripting (XSS) Vulnerabilities

A.

Cross-site scripting attacks inject malformed input.

Attackers who exploit weak application authentication controls can gain unauthorized access to applications and this has little to do with cross-site scripting vulnerabilities.

Attackers who exploit flawed cryptographic secure sockets layer (SSI.) implementations and short key lengths can sniff network traffic and crack keys to gain unauthorized access to information.

This has little to do with cross-site scripting vulnerabilities.

Web application trust relationships do not relate directly to the attack.

Cross-site scripting (XSS) attacks occur when an attacker injects malicious code, typically in the form of a script, into a web application that is then executed by unsuspecting users who view the web page. These attacks are possible due to a vulnerability in the web application that allows the attacker to inject the code.

The correct answer to the question is A. a lack of proper input validation controls.

Input validation is the process of checking the user's input to ensure that it meets the expected format and is safe to use within the web application. In the case of XSS attacks, the attacker is able to inject malicious code into the web application because the input validation controls are not properly implemented or are completely absent.

For example, an attacker could exploit an XSS vulnerability by submitting a form with malicious JavaScript code embedded in one of the fields. If the web application does not properly validate the input, the code will be executed when the page is loaded by another user.

Answer B, weak authentication controls in the web application layer, is incorrect because authentication controls relate to verifying the identity of a user, not validating input.

Answer C, flawed cryptographic SSL implementations and short key lengths, is also incorrect because XSS attacks do not typically involve cryptographic vulnerabilities.

Answer D, implicit web application trust relationships, is incorrect because trust relationships are not directly related to XSS attacks. Trust relationships relate to how different components of a system interact with each other, and are typically established through authentication and authorization mechanisms.

In summary, XSS attacks are possible when a web application does not properly validate user input, allowing an attacker to inject malicious code into the application.