Denial-of-service attack

Stachledraht DDos Attack

Denial-of-service attack

A Denial-of-service attack (DoS attack) is a cyber-attack in which the perpetrator seeks to make a machine or network resource unavailable to its intended users by temporarily or indefinitely disrupting services of a host connected to the Internet. Denial-of-service is typically accomplished by flooding the targeted machine or resource with superfluous requests in an attempt to overload systems and prevent some or all legitimate requests from being fulfilled.

Types of Denial-of-service attacks

There are several types of DoS attacks, including:

• Distributed Denial-of-service attack (DDoS): This type of attack involves multiple compromised computer systems attacking a target, such as a server, website, or other network resource, and causing a denial of service for users of the targeted resource.
• Application layer attacks: These attacks target the application layer (Layer 7 in the OSI model) and are designed to crash the web server or database.
• Protocol attacks: These attacks exploit weaknesses in the protocols used by the target system, such as TCP/IP, to cause a denial of service.
• Volumetric attacks: These attacks involve overwhelming the target with a high volume of traffic, such as UDP floods or ICMP floods.

Common Techniques

Some common techniques used in DoS attacks include:

• Ping of Death: Sending malformed or oversized packets using the ping command.
• SYN flood: Exploiting the TCP handshake process by sending a succession of SYN requests to a target's system.
• Teardrop attack: Sending fragmented packets to a target machine, which cannot reassemble them due to a bug in the TCP/IP fragmentation reassembly code.
• Smurf attack: Sending large numbers of ICMP packets with the intended victim's spoofed source IP to a network's broadcast address.

Prevention and Mitigation

Preventing and mitigating DoS attacks involves several strategies, including:

• Firewalls: Configuring firewalls to block traffic from known malicious IP addresses.
• Intrusion detection systems (IDS): Using IDS to detect and respond to unusual traffic patterns.
• Rate limiting: Implementing rate limiting to control the amount of traffic a server will accept.
• Content delivery networks (CDNs): Using CDNs to distribute traffic and reduce the impact of an attack.

Notable Incidents

Several high-profile DoS attacks have occurred, including:

• The GitHub DDoS attack in 2018, which was one of the largest DDoS attacks recorded.
• The Dyn cyberattack in 2016, which affected major websites such as Twitter, Netflix, and Reddit.

See Also

• Cybersecurity
• Botnet
• Firewall (computing)
• Intrusion detection system
• Network security
• TCP/IP

Related Pages

• Distributed Denial-of-service attack
• Cyber-attack
• Firewall (computing)
• Intrusion detection system
• Network security