Which type of attack occurs when malware is hidden within an application and infects the...

A trojan is malware disguised as legitimate or useful software. It tricks the user or system into running it, then performs malicious actions such as installing backdoors, stealing data, downloading additional payloads, or giving attackers remote access. The key characteristic is deception: the malware is hidden inside or presented as a trusted application. A botnet is a network of compromised devices controlled by an attacker, often through command-and-control infrastructure. Ransomware encrypts or locks systems and demands payment. A virus is malware that attaches to files or programs and replicates when executed, but the scenario specifically describes malicious code hidden within an application to avoid detection, which fits a trojan. Trojans are common because they exploit user trust and can bypass purely technical controls if users install unauthorized software. Endpoint protection, application control, user training, and least privilege help reduce trojan risk. Reference/topics: Cybersecurity 1.3, malware types; Endpoint Security 4.3, antivirus.