An attacker has tricked a user into executing content he placed on a social networking site. The malicious content executes in the victim's browser and allows the attacker to determine if machines behind the user's firewall are up and running. What type of attack is this?
The attack described involves executing content in the victim's browser after tricking them into clicking on a malicious link or executing content. This is characteristic of Cross Site Scripting (XSS). XSS attacks enable the attacker to run scripts in the context of the user's browser, potentially probing machines behind the user's firewall. SQL Injection, Account Harvesting, and Session Hijacking do not match the description of the attack in question as precisely as Cross Site Scripting.
This is a definition of XSS, correct answer is A