2025年7月9日、フロリダ州マイアミのABCファイナンシャルサービスでセキュリティ侵入テストが行われていた際、倫理ハッカーのハビエル・モラレスが同社のオンラインバンキングポータルを標的にし、その耐性を評価しました。数時間後、ポータルのウェブサーバーが不安定になり始め、正規ユーザーからログインや取引の完了ができなくなるという報告がありました。ITチームは、ネットワークトラフィック全体に大きな急増は見られなかったものの、サーバーが新規接続の受け入れに苦戦していることに気付きました。ハビエルが安全なシステムから実行した制御テストでは、実際の攻撃をシミュレートするためにインタラクションを記録し、ITチームの脅威識別能力を評価することを目指しました。
Javier の演習では、主にどのような DoS または DDoS 攻撃手法をシミュレートしていますか?
正解:A
The symptoms point directly to a Slowloris attack, which CEH materials classify as an application-layer denial-of-service technique that targets web servers by exhausting their available concurrent connection slots rather than saturating bandwidth. In a Slowloris attack, the attacker opens many HTTP or HTTPS connections to the server and then keeps them alive as long as possible by sending partial, incomplete HTTP requests or very slow header transmissions at timed intervals. Because the requests are never fully completed, the server keeps the connections open, waiting for the remainder of the request. Over time, the server's maximum connection limit is consumed, and legitimate users cannot establish new sessions, even though overall network traffic may remain relatively low.
That exact pattern is described in the scenario: the server is "struggling to accept new connections," the
"maximum connection limit is nearly reached," and there is "no significant spike in overall network traffic." This is a classic indicator of low-and-slow DoS behavior, which can be harder to detect because it does not resemble a high-volume flood.
A SYN Flood attack can also exhaust connection resources, but it typically creates a large number of half- open TCP connections and is usually more apparent in network-level telemetry and SYN backlog behavior. A UDP Flood generally causes a noticeable traffic spike. "Peer-to-Peer Attack" describes a botnet architecture style, not the specific technique used here. Therefore, the attack being simulated is Slowloris.