DDoS mitigation is a set of network management techniques and/or tools for resisting or mitigating the impact of distributed denial-of-service (DDoS) attacks on networks attached to the Internet by protecting the target and relay networks. DDoS attacks are a constant threat to businesses and organizations, delaying service performance or shutting down websites entirely. [1]
DDoS mitigation works by identifying baseline conditions for network traffic by analyzing "traffic patterns" to allow threat detection and alerting. [2] DDoS mitigation also requires identifying incoming traffic to separate human traffic from human-like bots and hijacked web browsers. This process involves comparing signatures and examining different attributes of the traffic, including IP addresses, cookie variations, HTTP headers, and browser fingerprints.
After the attack is detected, the next process is filtering. Filtering can be done through anti-DDoS technology like connection tracking, IP reputation lists, deep packet inspection, blacklisting/whitelisting, or rate limiting. [3] [4]
One technique is to pass network traffic addressed to a potential target network through high-capacity networks, with "traffic scrubbing" filters. [2]
Manual DDoS mitigation is no longer recommended due to the size of attacks often outstripping the human resources available in many firms/organizations. [5] Other methods to prevent DDoS attacks can be implemented, such as on-premises and/or cloud-based solution providers. On-premises mitigation technology (most commonly a hardware device) is often placed in front of the network. This would limit the maximum bandwidth available to what is provided by the Internet service provider. [6] Common methods involve hybrid solutions, by combining on-premises filtering with cloud-based solutions. [7]
DDoS attacks are executed against websites and networks of selected victims. A number of vendors offer "DDoS-resistant" hosting services, mostly based on techniques similar to content delivery networks. Distribution avoids a single point of congestion and prevents the DDoS attack from concentrating on a single target.
One technique of DDoS attacks is to use misconfigured third-party networks, allowing the amplification [8] of spoofed UDP packets. Proper configuration of network equipment, enabling ingress filtering and egress filtering, as documented in BCP 38 [9] and RFC 6959, [10] prevents amplification and spoofing, thus reducing the number of relay networks available to attackers.
In computing, a denial-of-service 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 a network. 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. The range of attacks varies widely, spanning from inundating a server with millions of requests to slow its performance, overwhelming a server with a substantial amount of invalid data, to submitting requests with an illegitimate IP address.
In computer networking, IP address spoofing or IP spoofing is the creation of Internet Protocol (IP) packets with a false source IP address, for the purpose of impersonating another computing system.
A Smurf attack is a distributed denial-of-service attack in which large numbers of Internet Control Message Protocol (ICMP) packets with the intended victim's spoofed source IP are broadcast to a computer network using an IP broadcast address. Most devices on a network will, by default, respond to this by sending a reply to the source IP address. If the number of machines on the network that receive and respond to these packets is very large, the victim's computer will be flooded with traffic. This can slow down the victim's computer to the point where it becomes impossible to work on.
Deep packet inspection (DPI) is a type of data processing that inspects in detail the data being sent over a computer network, and may take actions such as alerting, blocking, re-routing, or logging it accordingly. Deep packet inspection is often used for baselining application behavior, analyzing network usage, troubleshooting network performance, ensuring that data is in the correct format, checking for malicious code, eavesdropping, and internet censorship, among other purposes. There are multiple headers for IP packets; network equipment only needs to use the first of these for normal operation, but use of the second header is normally considered to be shallow packet inspection despite this definition.
A Martian packet is an IP packet seen on the public Internet that contains a source or destination address that is reserved for special use by the Internet Assigned Numbers Authority (IANA) as defined in RFC 1812, Appendix B Glossary. On the public Internet, such a packet either has a spoofed source address, and it cannot actually originate as claimed, or the packet cannot be delivered. The requirement to filter these packets is found in RFC 1812, Section 5.3.7.
Internet security is a branch of computer security. It encompasses the Internet, browser security, web site security, and network security as it applies to other applications or operating systems as a whole. Its objective is to establish rules and measures to use against attacks over the Internet. The Internet is an inherently insecure channel for information exchange, with high risk of intrusion or fraud, such as phishing, online viruses, trojans, ransomware and worms.
In computer networking, port knocking is a method of externally opening ports on a firewall by generating a connection attempt on a set of prespecified closed ports. Once a correct sequence of connection attempts is received, the firewall rules are dynamically modified to allow the host which sent the connection attempts to connect over specific port(s). A variant called single packet authorization (SPA) exists, where only a single "knock" is needed, consisting of an encrypted packet.
The Spamhaus Project is an international organisation based in the Principality of Andorra, founded in 1998 by Steve Linford to track email spammers and spam-related activity. The name spamhaus, a pseudo-German expression, was coined by Linford to refer to an internet service provider, or other firm, which spams or knowingly provides service to spammers.
Distributed denial-of-service attacks on root nameservers are Internet events in which distributed denial-of-service attacks target one or more of the thirteen Domain Name System root nameserver clusters. The root nameservers are critical infrastructure components of the Internet, mapping domain names to IP addresses and other resource record (RR) data.
IP traceback is any method for reliably determining the origin of a packet on the Internet. The IP protocol does not provide for the authentication of the source IP address of an IP packet, enabling the source address to be falsified in a strategy called IP address spoofing, and creating potential internet security and stability problems.
A ping of death is a type of attack on a computer system that involves sending a malformed or otherwise malicious ping to a computer. In this attack, a host sends hundreds of ping requests with a packet size that is large or illegal to another host to try to take it offline or to keep it preoccupied responding with ICMP Echo replies.
Reverse-path forwarding (RPF) is a technique used in modern routers for the purposes of ensuring loop-free forwarding of multicast packets in multicast routing and to help prevent IP address spoofing in unicast routing.
In computer networking, ingress filtering is a technique used to ensure that incoming packets are actually from the networks from which they claim to originate. This can be used as a countermeasure against various spoofing attacks where the attacker's packets contain fake IP addresses. Spoofing is often used in denial-of-service attacks, and mitigating these is a primary application of ingress filtering.
In networking, a black hole refers to a place in the network where incoming or outgoing traffic is silently discarded, without informing the source that the data did not reach its intended recipient.
A forwarding information base (FIB), also known as a forwarding table or MAC table, is most commonly used in network bridging, routing, and similar functions to find the proper output network interface controller to which the input interface should forward a packet. It is a dynamic table that maps MAC addresses to ports. It is the essential mechanism that separates network switches from Ethernet hubs. Content-addressable memory (CAM) is typically used to efficiently implement the FIB, thus it is sometimes called a CAM table.
Network behavior anomaly detection (NBAD) is a security technique that provides network security threat detection. It is a complementary technology to systems that detect security threats based on packet signatures.
In computing, a firewall is a network security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules. A firewall typically establishes a barrier between a trusted network and an untrusted network, such as the Internet.
A next-generation firewall (NGFW) is a part of the third generation of firewall technology, combining a conventional firewall with other network device filtering functions, such as an application firewall using in-line deep packet inspection (DPI) and an intrusion prevention system (IPS). Other techniques might also be employed, such as TLS-encrypted traffic inspection, website filtering, QoS/bandwidth management, antivirus inspection, third-party identity management integration, and SSL decryption
The BlackNurse attack is a form of denial of service attack based on ICMP flooding. The attack is special because a modest bandwidth of 20 Mbit/s can be effective for disrupting a victim's network.
Data center security is the set of policies, precautions and practices adopted at a data center to avoid unauthorized access and manipulation of its resources. The data center houses the enterprise applications and data, hence why providing a proper security system is critical. Denial of service (DoS), theft of confidential information, data alteration, and data loss are some of the common security problems afflicting data center environments.
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