問56
頻出度★★★
PC 内のファイルを暗号化して使用不能にし，復号するためのキーと引換えに金品を要求するソフトウェアを何と呼ぶか。
平成29年度 秋期 ITパスポート試験 問56
テクノロジ系セキュリティ › 情報セキュリティ
This question's explanation and your answers so far.
解説
問 56
Incorrectア
A keylogger is software that records what is typed on the keyboard and sends it to an outside party; it is used to steal passwords, credit card numbers, and the like. It does not encrypt files or demand money, so it is incorrect.
- イ
正解 The correct answer is “イ Ransomware.” Ransomware is a coined word combining “ransom” and “software”; it is malware that, without permission, encrypts the files on an infected PC so they cannot be opened, and demands money (a ransom) in exchange for the key needed to restore (decrypt) them. This matches exactly the question’s description of software that encrypts files to make them unusable and demands money in exchange for a decryption key.
Incorrectウ
A rootkit is a set of tools that an attacker uses after breaking in to conceal their own presence and illicit activity and to maintain the intrusion with administrator privileges. Its purpose is concealment; it does not encrypt files or demand money, so it is incorrect.
Incorrectエ
A worm is malware that self-replicates and spreads infection from one computer to the next across a network. Its defining trait is replication and propagation, which differs from the question’s description of demanding a ransom through encryption, so it is incorrect.
ここがポイント
- Master the definition of ransomware: malware that encrypts files to hold them hostage and demands a ransom (money) in exchange for the decryption key.
- Distinguish the representative types of malware: keylogger (eavesdropping on input), rootkit (concealing intrusion and activity), and worm (self-replication and propagation); tell them apart by their purpose and method.
用語