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DoS
A Denial-of-Service (DoS) attack occurs when attackers overload a system with excessive requests, making it unavailable to intended users. DoS attacks often originate from a single source, and can be identified by sudden network slowdowns, connectivity loss, and access issues.
What is a Denial-of-Service (DoS) attack?
A Denial-of-Service (DoS) attack is a type of cyber threat in which culprits aim to make a computer or a network resource unavailable to intended users by disrupting its regular operations. DoS attacks operate through inundating the targeted system with excessive requests to such an extent that it can no longer respond to normal traffic. This causes a denial of service to other users. One distinguishing characteristic of a DoS attack is its origin from a single system.
Distributed Denial-of-Service (DDoS) attacks, however, emanate from various diverse sources, often in the form of a botnet.
What happens during a DoS attack?
The primary objective of a DoS attack is to exceed the processing capabilities of a targeted system, resulting in denial of service for subsequent requests. These attacks can originate through various techniques, often grouped according to their similarities.
DoS attacks mainly fall under two categories:
Buffer overflow attacks
This type of attack involves overwhelming a computer’s memory buffer to such an extent that it consumes all available disk space, memory, or CPU time. The consequential effects usually include slowed system performance, system crashes, and other negative impacts on server functionality – resulting in denial-of-service.
Flood attacks
These attacks involve bombing a targeted server with an excessive amount of packets. The invasion succeeds if the attacker has higher bandwidth than the target, resulting in overwhelming the server’s capacity and causing a service denial.
Which are some common forms of DoS attacks?
Some of common forms of DoS attacks include:
- Ping Flood: This simple yet effective DoS attack overwhelms a target with an avalanche of ICMP (ping) packets. If the target cannot handle this pressure efficiently, a service denial can occur. It can also be a DDoS attack.
- Ping of Death: Often confused with a Ping Flood, this attack sends a distorted packet to a target system, resulting in a system crash.
- Smurf Attack: This attack exploits a network’s vulnerability by sending spoofed packets, leading to a flood of a targeted IP address.
Historically, DoS attacks were more common, exploiting vulnerabilities in network, software, and hardware design. However, DDoS attacks have now taken the lead, given their greater disruptive capacity and relative ease in execution. Any DoS attack can evolve into a DDoS attack.
How can you identify a DoS attack?
While it’s challenging to distinguish between an attack and typical network issues or high bandwidth consumption, certain indicators can hint at an ongoing attack.
Warning signs for a DoS attack include:
- Sudden loss of network connectivity on multiple systems
- Unusually slow network performance leading to delays in loading files or websites
- An unexpected inability to access certain websites
What’s the difference between a DoS and DDoS attack?
The key difference between DoS and DDoS attacks lies in the volume of connections exploited. DoS attacks, in contrast to DDoS, operate from a single connection. DDoS attacks harness multiple sources of illegitimate traffic, often utilizing a botnet.
Fundamentally, regardless of the number of sources, most attacks share the same process and can be initiated using one or more sources of malicious traffic.
