問97
頻出度★★★
情報セキュリティにおいて, 可用性が損なわれた事象だけを全て挙げたものはどれか。 a 関連取引先との電子決済システムが DoS 攻撃を受け, 処理ができなくなった。 b 顧客情報管理システムの顧客情報が誤った内容のまま運用されていた。 c 社内のサーバに不正侵入されて, 社外秘の情報が漏えいした。
令和7年度 ITパスポート試験 問97
テクノロジ系セキュリティ › 情報セキュリティ管理
This question's explanation and your answers so far.
解説
問 97
- ア
正解 The three elements of information security are confidentiality, integrity, and availability. Availability means that authorized users can use systems or information whenever they need to. Among the three events, the only one in which availability was impaired is a. In a, the electronic settlement system was hit by a DoS attack and could no longer process transactions—that is, the system could not be used when needed—so it is a breach of availability. Event b is a breach of integrity and c of confidentiality; neither concerns availability. Only a lists an event where availability was impaired, so the correct answer is ア (a).
Incorrectイ
This adds b on top of a (availability), but b is the event where customer data was used with incorrect content, meaning the accuracy and consistency of the data could not be maintained—a breach of integrity, not availability. So this option, which includes b, is wrong.
Incorrectウ
This lists b and c, but b is a breach of integrity and c is the leak of confidential information—a breach of confidentiality; neither is a breach of availability. It omits a, which does concern availability, and lists only non-availability events, so it is wrong.
Incorrectエ
This lists only c, but c is the leak of confidential information caused by an intrusion—a breach of confidentiality, not availability. Because it does not include a, where availability was impaired, it is wrong.
ここがポイント
- The three elements of information security (CIA): confidentiality = only authorized persons can access the information; integrity = the information is accurate and free of tampering or errors; availability = the information or system can be used when needed.
- Typical examples of impaired availability are DoS attacks, failures, or outages that make something unusable. A leak is classified under confidentiality, and operating with incorrect content (lack of accuracy) under integrity.
用語