Hack Your Way to Success: 2025 Ethical Hacking Essentials Challenge – Level Up Your Skills!

The Agent Smith attack specifically describes a type of malicious activity where legitimate applications on a user's device are replaced with compromised versions that display unwanted advertisements. This form of attack operates stealthily, exploiting vulnerabilities in apps, typically focusing on popular applications to maximize its reach. The replaced apps become agents, promoting fraudulent activities such as ad fraud without the user’s consent or knowledge.

In contrast to other options, ad fraud more generally refers to fraudulent practices used to generate revenue from advertisements rather than the specific technique of replacing legitimate apps. Similarly, ad injection involves modifying legitimate ad content rather than substituting applications entirely. Lastly, spyware installation refers to software designed to gather information without the user’s knowledge, which is not primarily focused on advertisement generation. This distinction underscores why the Agent Smith attack is the correct answer in the context of replacing legitimate apps for advertising purposes.