ITPEC IP October 2025 Question 45

It encrypts the files of a PC and demands money for the decryption key — ransomware holds the victim's data to ransom.

Ransomware, once it infects a PC, encrypts the files on it (and often on the file servers it can reach) without permission and displays a demand for payment, usually in cryptocurrency, in exchange for the key to decrypt them. Paying does not guarantee the files come back, so the defence is prevention plus backups kept offline, where the ransomware cannot encrypt them too.

Answer (b)

Why not others:

• •(a) — secretly creating an entry route so an attacker can log in from outside later is a backdoor
• •(c) — taking over the web browser to alter online-banking traffic and send money elsewhere is a man-in-the-browser (MITB) attack
• •(d) — spreading itself over a network without a host program is the defining feature of a worm

Key rule: Name malware by what it does: ransomware encrypts and extorts, a backdoor opens a hidden way in, MITB alters transactions in the browser, and a worm copies itself across networks.

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