問100
頻出度★★★
脆弱性のある IoT 機器が幾つかの企業に多数設置されていた。その機器の1台にマルウェアが感染し，他の多数の IoT 機器にマルウェア感染が拡大した。ある日のある時刻に，マルウェアに感染した多数の IoT 機器が特定の Web サイトへ一斉に大量のアクセスを行い，Web サイトのサービスを停止に追い込んだ。この Web サイトが受けた攻撃はどれか。
令和元年度 秋期 ITパスポート試験 問100
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 100
- ア
正解 The correct answer is ア 'DDoS attack'. DDoS (Distributed Denial of Service) is an attack that uses a large number of devices that have been infected with malware and taken over (a botnet) as stepping stones, sending a massive volume of accesses or packets from them to a target server all at once to saturate its processing capacity and network line, thereby forcing the service for legitimate users to shut down. This question states that vulnerable IoT devices became infected with malware, the infection spread, and many infected devices simultaneously sent a massive volume of accesses to a specific website and shut the service down — which perfectly matches the DDoS characteristics of 'from many distributed devices', 'a massive volume of accesses all at once', and 'service shutdown'.
Incorrectイ
Cross-Site Scripting (XSS) is an attack that abuses input fields and the like on a vulnerable website to embed a malicious script, causing the script to run in the browser of a user who views that page, aiming at stealing Cookies, impersonation, and so on. It is not an attack that shuts down a service through a massive volume of accesses.
Incorrectウ
A dictionary attack is an unauthorized-login technique that tries, one after another, words listed in a dictionary or commonly used character strings in an attempt to crack a password. Its purpose is to crack a password, which differs from the situation in this question of stopping a service through a massive volume of accesses from many devices.
Incorrectエ
Social engineering is a non-technical technique that steals confidential information by exploiting human psychological gaps or behavioral mistakes, such as impersonation phone calls or shoulder surfing. It has nothing to do with a technical attack in the form of a massive volume of accesses by IoT devices.
ここがポイント
- DDoS attack = an attack that uses a large number of devices taken over via malware infection (a botnet) as stepping stones, sending a massive volume of accesses to a target from many distributed locations all at once, thereby shutting down the service.
- An attack from a single device is called a DoS attack, while one distributed across a large number of devices is called a DDoS attack — the two are distinguished. 'Many IoT devices acting all at once' is the decisive clue for DDoS.
用語