Many of us have been affected by cyberattacks that disrupt a website or network. This results in lost revenue and a damaged reputation and can cost substantial sums for security and service recovery. The most common such attacks are DoS and DDoS. Fortunately, there are ways to identify such incidents quickly.
Denial of Service (DoS) Attacks
Understanding the distinction between DOS vs DDOS attacks is crucial for implementing effective defense strategies against different scales of disruptive cyber threats. DoS attacks clog a server’s resources so that it can no longer handle legitimate traffic. These attacks can last for hours, days, or even months, depriving online users of the necessary information and services. DoS attackers range from hacktivists seeking to make a political statement or champion a cause to profit-motivated cybercriminals and nation-states. The attack type and scale can vary, but all types of DoS attacks rely on the same principle of overwhelming the target with more data than it can handle. This can happen in several ways, including launching a massive flood of traffic that drowns out legitimate requests or triggering vulnerabilities that lead to a website crash. A 13-year-old can claim credit for the first DoS attack in 1974, which forced computers at a university research lab to power down. Today, more sophisticated attacks use distributed networks of malware-infected computers or devices to coordinate a barrage of meaningless traffic against the targeted server. These coordinated assaults are DDoS attacks and can be much harder to stop than single-machine DoS attacks. Another type of DoS attack is the reflected DoS (RDoS) attack, which spoofs the device’s IP address. This attack can send hundreds or thousands of “introduction” messages to a server, each taking up to a minute for the server to respond.
Distributed Denial of Service (DDoS) Attacks
DoS attacks force web servers and online systems to shut down by flooding traffic. The attack can be as simple as a single computer sending an overwhelming flux of incoming messages, connection requests, or malformed packets. As the attack chokes the targeted system, legitimate users are denied access to the network or application. In a more sophisticated variation of a DoS attack, hackers enlist armies of compromised computers to conduct the denial of service. These attackers, often called bots, are connected to the internet using malware, enabling them to execute multiple tasks simultaneously. For example, the bots in a DDoS attack could be commanded to scan for vulnerable devices and then infect them with a Trojan virus. Once a bot is infected, it will send an overwhelming flood of bogus data to a server or network.
A DDoS attack can last from a few seconds to weeks, depending on the complexity of the attack. During this time, your business may experience loss of revenues, lost customers, eroded consumer confidence, and long-term reputation damage. Fortunately, there are tried and true approaches to prevent DDoS attacks. A well-established security infrastructure will detect any abnormal increase in network traffic to a specific endpoint (e.g., a website). It can also identify traffic patterns that look suspiciously like a DDoS attack.
Defending Against DoS Attacks
DoS attacks can have various apparent effects, depending on the target. For example, a retail site might suddenly stop displaying its content; an online marketplace could lose its ability to process transactions or make available inventory. If the attack targets industrial control systems, it may fail to retrieve sensor data or halt critical processes. Dos attacks can target networks, services, and applications at the network or application layers. Overload-based attacks at the network layer attempt to consume capacity on a service’s underlying networking infrastructure by opening up too many connections or taxing server resources with compute-expensive functionality. For example, in a SYN flood attack, an attacker opens multiple connections to a server and never closes them, overwhelming the server with requests and draining its resources. Application-layer DoS attacks are more complex to detect and mitigate but can still be damaging. The good news is that both kinds of DoS attacks can be mitigated with a combination of network security and monitoring solutions and a plan for what to do when an attack occurs. It’s essential to establish a baseline for regular network activity and then be alerted when significant changes might signal an attack, such as surges in traffic from the same source or a noticeable reduction in service availability.
Protecting Against DDoS Attacks
A DDoS attack starts with an influx of traffic beyond the targeted system’s capacity, slowing it down or causing it to stop working altogether. The hacker may seek monetary compensation for their actions or make a political statement. Regardless of the motivation, it’s essential to know how to defend against DDoS attacks and to identify the signs. The most common way to identify a DDoS attack is by monitoring internet and network traffic. Firewall monitoring tools, cloud usage solutions, and other monitoring systems can catch surges in traffic that look suspicious and provide early warning of potential issues. Often, these systems will also be able to identify the type of DDoS attack that has occurred and provide valuable forensic information about the attacker. Whether running a small business or a large enterprise, you must invest in solutions blocking DDoS attacks. Many of these attacks are powered by botnets or networks of hijacked devices (such as PCs, cellphones, and unsecured IoT gadgets) controlled remotely from a command center. The hackers in the botnets can then use them to flood websites, servers, and other systems with overwhelming amounts of data packets they can no longer process. DDoS attack protection solutions typically include a combination of techniques, including bandwidth-saturating floods and layer seven attacks that target application services. They may also include a mitigation service that leverages DNS to reduce the impact of attacks on networks and end systems.