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| DoS, DoS attacks and security |
□ What is DoS?
DoS stands for Denial of Service. It is a type of cyber attack that aims to disrupt the normal functioning of a network, system or service, making it inaccessible to the intended user. The goal of a DoS attack is to overwhelm the target with illegitimate requests or excessive traffic, thereby depleting resources and making them unavailable to legitimate users.
□ Techniques used in DoS attacks
There are several techniques used to perform DoS attacks, including:
▶ Flooding Attack
This includes sending large amounts of traffic, such as Internet Control Message Protocol (ICMP) packets, to a target network or system, overwhelming its ability to handle legitimate requests.
▶ SYN flood attack
In this type of attack, the attacker sends a large number of SYN (synchronization) requests to the target server, but does not respond to the server's SYN-ACK (synchronization acknowledgment) response. This causes the server to allocate resources while waiting for final acknowledgment, eventually exhausting its capacity to handle new connections.
▶ Smurf attack
These attacks include attacks that exploit network broadcast addresses. An attacker sends multiple ICMP echo requests (pings) to an IP broadcast address, and the source address is spoofed to appear as the IP address of the target. This causes all hosts on the network to respond simultaneously, flooding the target with more traffic than it can handle.
▶ DDoS (Distributed Denial of Service) attack
DDoS attacks involve multiple compromised computers known as botnets, which are coordinated to simultaneously send large amounts of traffic or requests to the target. This distributed approach blocks a single source, making attacks difficult to mitigate.
□ DoS attack security
Mitigating a DoS attack usually requires the implementation of various security measures, such as:
▶ Traffic filtering
Filtering and blocking suspicious or malicious traffic at the network perimeter can help reduce the impact of DoS attacks.
▶ Intrusion Detection and Prevention System (IDPS)
These systems can detect and block DoS attack patterns, preventing them from reaching the target network or system.
▶ Load Balancing
Distributing network or system load across multiple servers or resources can mitigate the effects of a DoS attack by ensuring that no single component is overloaded.
▶ Speed limit
Implementing rate limiting measures limits the number of requests or connections from a single source, preventing individual attackers from overwhelming their targets.
DoS attacks are illegal and unethical when conducted without authorization, but organizations and security professionals should note that controlled testing called “penetration testing” or “ethical hacking” identifies vulnerabilities and strengthens defenses against such attacks. do.
□ Difference between DoS and DDoS
The difference between a DDoS attack and a DoS attack is that because a DDoS attack originates from multiple locations, it can spread much faster than a DoS attack originating from a single location.
Denial of Service (DoS) and Distributed Denial of Service (DDoS) both refer to denial of service attacks, but there are important differences between them.
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| Difference between DoS and DDoS |
▶ DoS (Denial of Service)
A DoS attack is an attack in which an attacker sends a large amount of traffic or requests to a specific target using a single computer or network to paralyze the service. These attacks usually proceed from a single source IP address, and the target of the attack is usually a single system or network. The impact of a DoS attack is limited because the attacker is targeting one device or computer at a time.
▶ DDoS (Distributed Denial of Service)
A DDoS attack is an advanced form of DoS attack, in which multiple computers or devices cooperate to carry out an attack. These devices are usually distributed around the world, and an attacker can manipulate them to simultaneously send large amounts of traffic or requests to the target. The attack can have far more powerful and devastating effects than a single-device DoS attack. Attackers usually use malware, or zombie networks (botnets), to take control of these devices.
