問68
頻出度★★★
サーバに対する DoS 攻撃のねらいはどれか。
平成21年度 春期 ITパスポート試験 問68
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 68
Incorrectア
Seizing the server administrator’s privileges is the aim of attacks that go after unauthorized access or privilege escalation (password cracking, intrusion that exploits a buffer overflow, and so on). A DoS attack merely makes the server unusable; it does not aim to have the attacker log in to the server and become the administrator.
- イ
正解 The correct answer is イ. A DoS attack (Denial of Service attack) sends a huge number of requests or packets to the target server, or exploits a vulnerability to make it perform abnormal processing, so that resources such as CPU, memory and line bandwidth are used up. As a result the server becomes extremely slow to respond or stops altogether, and the intended users can no longer receive the service. In other words, the aim of a DoS attack is not to obtain information inside the server but to disrupt the provision of the service itself and make it unusable — that is, to violate availability, one of the three elements of information security. Choice イ states exactly this, so it is correct. Remember it from the name: the attacker’s goal is to make the server “deny service”.
Incorrectウ
Tampering with data is the aim of attacks that violate the integrity of information, such as web page defacement or SQL injection. A DoS attack exhausts resources in order to stop the service; it does not aim to rewrite the content of stored data.
Incorrectエ
Stealing data is the aim of attacks such as eavesdropping (sniffing), phishing and information leakage, and it is an act that violates confidentiality. A DoS attack does not take information out; it aims to stop the service and make it unavailable, which is the difference.
ここがポイント
- DoS attack = Denial of Service attack. Its aim is to exhaust the server’s resources with a flood of requests or packets so that legitimate users are left unable to use the service. The form in which many hijacked machines are used as stepping stones to attack all at once is called a DDoS (Distributed Denial of Service) attack.
- It is easier to understand the aims of attacks by organizing them with the three elements of information security: eavesdropping and stealing information violate confidentiality, tampering violates integrity, and DoS / DDoS attacks violate availability.
用語