To answer this question, you need to understand the various techniques used for securing web applications against authenticated users. Let's go through each option to understand why it is correct or incorrect:
Option A) Client-side data validation - This option is NOT recommended for securing web applications against authenticated users. Client-side data validation can easily be bypassed by attackers, as they have complete control over the client-side code. The validation should always be performed on the server-side to ensure the integrity and security of the application.
Option B) Running the application under least privileges necessary - This option is recommended for securing web applications against authenticated users. By running the application under the least privileges necessary, you limit the potential damage an attacker can do if they gain access to the application. This principle is known as the principle of least privilege.
Option C) Filtering data with a default deny regular expression - This option is recommended for securing web applications against authenticated users. By using a default deny regular expression, you ensure that only the allowed characters and patterns are accepted, while rejecting everything else. This helps prevent attacks such as SQL injection, cross-site scripting (XSS), and other input validation vulnerabilities.
Option D) Using parameterized queries to access a database - This option is recommended for securing web applications against authenticated users. Parameterized queries help prevent SQL injection attacks by separating the SQL code from the user-supplied input. This ensures that the input is treated as data and not as part of the SQL code.
The correct answer is A) Client-side data validation. This option is NOT recommended for securing web applications against authenticated users because it can easily be bypassed by attackers. Server-side validation is essential for ensuring the security and integrity of the application.