A malware, that looks like a legitimate software and once it tricks a user into installing it, acts pretty much like a virus or worm, is known as:

Question

UnlockIAS · Accepted Answer

Correct — C, Trojan. A Trojan (Trojan horse) is malware that disguises itself as legitimate, useful software — a free utility, a cracked application, a game, an email attachment or an installer — so that the user voluntarily runs it. Deception at the point of entry is its defining feature, which is exactly what the stem describes ('looks like a legitimate software and… tricks a user into installing it'). Once installed it delivers a payload — opening a backdoor for remote control, stealing data, or dropping further malware — so it then behaves much like a virus or worm. The one thing it does not do is replicate itself: a virus needs a host file, a worm spreads across a network on its own, while a Trojan needs a fooled human. The name comes from the wooden horse of Troy.

Why the other options are wrong — (a) A keylogger is defined by what it does after entry — it records keystrokes to capture passwords, PINs and card numbers. It is a surveillance payload, and is often delivered by a Trojan rather than being the disguise itself.  (b) Ransomware encrypts files or locks the device and then demands payment — it announces itself loudly, which is the opposite of the 'looks legitimate' behaviour described. It is a payload category, not a disguise.  (d) Spyware covertly monitors activity and exfiltrates data. Its defining trait is stealthy surveillance after it is already inside, not masquerading as legitimate software to get in.

Concept: Malware is classified on two independent axes, and mixing them up is what makes these questions look hard. The first axis is how it spreads: a virus attaches to a host file and travels when that file is run; a worm self-replicates and moves across networks by itself; a Trojan does not replicate at all — it relies on tricking the user into installing it. The second axis is what it does once inside — the payload: ransomware (encrypt and extort), spyware and keyloggers (covert surveillance), adware, botnet agents. A single piece of malware can be a Trojan on the first axis and ransomware on the second.

State PCS 2025 Q22 — Science & Technology PYQ with Answer

State PCS 2025 Q22 — Science & Technology PYQ with Answer