CompTIA Security Plus Mock Test Q750

Which of the following is the BEST way to prevent Cross-Site Request Forgery (XSRF) attacks?

A. Check the referrer field in the HTTP header
B. Disable Flash content
C. Use only cookies for authentication
D. Use only HTTPS URLs

Correct Answer: A
Section: Application, Data and Host Security

XSRF or cross-site request forgery applies to web applications and is an attack that exploits the web application’s trust of a user who known or is supposed to have been
authenticated. This is accomplished by changing values in the HTTP header and even in the user’s cookie to falsify access. It can be prevented by embedding additional authentication
data into requests that allows the web application to detect requests from unauthorized locations. Examples are synchronizer token patterns, cookie-to-header tokens, and checking
the HTTP Referrer header and the HTTP Origin header.

Incorrect Answers:
B: Flash content is not used on Cross-Site Request Forgery (XSRF) attacks. Disabling flash content would thus not prevent Cross-Site Request Forgery (XSRF) attacks.
C: Cookies are plain-text files that a browser stores on a user’s hard disk to provide a persistent, customized web experience for each visit to a web site. It typically contains
information about the user but is not used for authentication.
D: HTTP Secure (HTTPS) combines HTTP with SSL/TLS to provide encrypted communication. This does not prevent XSRF.

Dulaney, Emmett and Chuck Eastton, CompTIA Security+ Study Guide, 6th Edition, Sybex, Indianapolis, 2014, pp. 75, 335, 339, 340-341