Application Layer DDoS (Distributed Denial of Service) attacks target the topmost layer in the OSI model of computer networking, the application layer. This layer is where end-user processes and applications operate, making it a critical point of interaction between users and network services.
Unlike lower-level DDoS attacks that target network infrastructure, Application Layer attacks are more nuanced. They focus on specific vulnerabilities or issues within the application itself. The goal is to disrupt the normal functioning of applications, ranging from web servers to other application services such as SIP (Session Initiation Protocol), voice services, and BGP (Border Gateway Protocol).
These attacks are insidious because they often mimic legitimate requests, making them harder to detect and mitigate. They exploit weaknesses in the application, causing it to fail in delivering content or services to the user. For example, an attacker might flood a web server with seemingly legitimate HTTP requests, which can overload the server and render it unable to process genuine user requests.
Application Layer DDoS attacks are typically low-to-mid volume in nature. This is because they need to conform to the specific protocol used by the application, which usually involves protocol handshakes and compliance with application norms. High-volume attacks at this layer are less common as they can be more easily detected and mitigated.
A distinctive aspect of these attacks is the use of discrete intelligent clients, often consisting of compromised Internet of Things (IoT) devices. These devices are utilized to launch coordinated attacks against targeted applications. Unlike some other forms of DDoS attacks, those at the application layer cannot usually be spoofed, meaning the attacking devices can be identified.
To counter these sophisticated attacks, solutions like NETSCOUT’s Omnis AED are employed. This tool is designed to provide robust hybrid DDoS protection. It operates on the network’s perimeter, protecting against various attacks, including those at the application layer. It uses a blend of on-premises and cloud-based defenses to detect and mitigate these attacks, ensuring the continuous availability of applications and services.
In summary, Application Layer DDoS attacks are a sophisticated form of cyber threat that targets the functional aspects of applications. They require specialized detection and mitigation strategies due to their compliance with standard protocols and the use of legitimate-looking requests.