What is a flood attack? Explanation of core principles and typical types

in the digital wave, cyber security threats are penetrating various scenarios in various forms, among which flooding attacks have become a common attack method for black industries with low cost and high destructive power. Such attacks do not require complex technical thresholds, but can easily paralyze small and medium-sized websites, Enterprise Services and even some public network nodes. This article will start from the dimensions of core principles and typical types, systematically explain the operation logic and defense direction of flooding attacks, and build a complete cognitive framework for readers.

What is the core principle of flood attack?

to understand the harm of flooding attacks, we must first clarify its underlying operating logic, which is the basis for identifying and defending against such attacks.

1, resource exhaustion core logic

flooding attack is resource exhaustion. The attacker uses the target's bandwidth, memory, CPU and other core resources by sending requests or data packets that far exceed its carrying capacity, resulting in the target being unable to process the legitimate requests of normal users. Unlike targeted exploits, flooding attacks rely on the accumulation of "volume" to achieve damage, even if the target system has no obvious vulnerabilities, it may be dragged down by such attacks.

2, fake source address covert feature

most flooding attacks use forged Internet Protocol Addresses to make it impossible for the target server to trace the true source of the attack, and to avoid the attack traffic being traced back to the source. Forged source addresses distract the target's defense attention, making it impossible to block the attack through simple IP blocking, further enhancing the stealth and continuous destructive power of flooding attacks.

What are the typical types of flooding attacks?

flood attack is not a single form, according to the different targets and technical means, can be divided into a variety of typical types, each type of attack scenarios and harm are also different.

1, UDP flooding attack

UDP flooding attack is a form of attack against connectionless protocol. The attacker sends a large number of forged data packets to the random UDP port of the target server. The server will try to respond to these data packets after receiving, but because the source address is forged, the response packet cannot be delivered. Eventually, the server's bandwidth and connection resources are continuously occupied. This type of attack is often used to attack nodes that rely on the UDP protocol such as DNS servers and video streaming servers.

2, TCP SYN flooding attack

TCP SYN flooding attack takes advantage of the design flaw of TCP three-way handshake. After the attacker sends a large number of SYN connection requests to the target, it does not respond to the server's SYN + ACK packets, resulting in the server maintaining a large number of semi-connected states, occupying system memory and connection queue resources. When the number of half-connections exceeds the upper limit of the server bearer, the connection request of normal users will be directly rejected, and eventually the server will be paralyzed.

3, HTTP flooding attack

HTTP flood attack is an application layer attack. The attacker sends a large number of legitimate HTTP requests to the target website by controlling a large number of puppet hosts, such as repeatedly refreshing pages and submitting forms. This kind of attack traffic is almost indistinguishable from normal user requests, and it is difficult to identify through traditional traffic cleaning equipment. It is often used to attack public-facing Web services such as e-commerce platforms and portals.

III. Main harms and effects of flood attacks?

flood attack is not only reflected in the system paralysis level, but also triggers a series of chain reactions, causing multiple losses to enterprises and users.

1, business interruption direct loss

flood attack the most direct harm is business interruption, for the e-commerce platform, the loss of orders during the attack, customer complaints will directly cause economic losses; for the internal system of the enterprise, the server paralysis will lead to stagnation of office processes, data processing interruption, affecting the normal operation of the enterprise. Some attacks will even last for hours or even days, bringing immeasurable losses to the enterprise.

2, brand reputation indirect damage

companies that are frequently subject to flooding attacks will make users question their cyber security capabilities, which in turn affects brand reputation. Especially in fields with extremely high security requirements such as finance and government affairs, the service interruption caused by a flooding attack may lead to a significant drop in user trust, and even trigger a chain reaction of user churn.

What are the basic defensive means of flood attack?

the characteristics of flooding attacks, the industry has formed a mature basic defense system, from traffic identification to resource optimization multi-dimensional construction of protective barriers.

1, flow cleaning and anomaly detection

deployment of professional traffic cleaning equipment is the core means to defend against flooding attacks. Such equipment can monitor network traffic in real time. By identifying abnormal traffic characteristics such as data packet frequency, source address distribution, etc., the attack traffic is separated from the legitimate traffic, and only the legitimate traffic is forwarded to the target server. At the same time, combined with the anomaly detection model of machine learning algorithms, flooding attacks disguised as legitimate requests can be more accurately identified.

2, resource expansion and protocol optimization

by expanding the server bandwidth, CPU, memory and other hardware resources, it can improve the carrying capacity of the target system for flooding attacks and gain time for traffic cleaning. In addition, for TCP SYN flooding attacks, protocol optimization methods such as adjusting the timeout time of TCP half connection and enabling SYN Cookies can reduce the occupation of system resources by half connection and improve the anti-attack ability of the system.

To sum up, flooding attack is a kind of network attack with resource exhaustion as the core, covering UDP, TCP SYN, HTTP and other typical types, which has the characteristics of strong concealment and destructive power. By understanding its core principle and harm, combined with traffic cleaning, resource expansion and other defense means, the risk of flooding attack can be effectively reduced. In the current cyber security situation is increasingly severe, mastering the cognition and defense points of such attacks is an important part of improving cyber security protection capabilities.