問66
頻出度★★★
PC で電子メールの本文に記載されていた URL にアクセスしたところ, 画面に図のメッセージが表示され, PC がロックされてしまった。これは, 何による攻撃か。
平成30年度 春期 ITパスポート試験 問66
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 66
Incorrectア
A keylogger is malware that secretly records keyboard input to steal entered passwords, credit card numbers, and the like. Its purpose is stealing information; it does not lock the PC on screen and demand a ransom. This does not match the message in the figure.
Incorrectイ
Spyware is malware that collects personal information and activity history without the user noticing and sends it to an outside attacker. Its defining trait is running covertly; it does not display a lock screen of its own to demand money. It does not carry out open threats like the one in the figure.
Incorrectウ
A bot is malware that lets an attacker remotely control an infected PC; many bots bundled together form a botnet, which is used as a stepping stone for DDoS attacks or sending spam email. Its action is not to lock the PC and demand an unlocking fee, so it does not match the message in the figure.
- エ
正解 Choice エ, ransomware. The message in the figure says the PC has been locked, that a password is required to unlock it, that a payment must be made within 48 hours, and that unlocking will become impossible if no payment is made. In other words, the malware locks (or encrypts) the PC so it cannot be used and demands money (a ransom) in exchange for unlocking and recovering it. This behavior of holding data or a system hostage in order to demand a ransom is the very definition of ransomware, and the fact that the infection route is accessing a URL in an email body also fits a typical example. Therefore エ is correct.
ここがポイント
- Ransomware = malware that encrypts the files on an infected PC or locks the system so it cannot be used, and demands a ransom (money) in exchange for recovery. It is named after ransom.
- The main infection routes are malicious URLs or files in the body of an email or in attachments; what distinguishes it from the keylogger, spyware, and bot in the other choices is that it holds data or a system hostage in order to demand money.
用語