What is a DDoS attack?
A distributed denial of service DDoS attack is a malicious attempt to disrupt regular traffic to a targeted server, service, or network by flooding the target or its surrounding infrastructure with Internet traffic.
DDoS assaults are effective because they use numerous compromised computer systems as attack traffic sources.
Computers and other networked resources, like as IoT devices, can all be exploited machines.
What is a ddos attack A DDoS attack is analogous to an unforeseen traffic jam filling up the roadway, preventing regular traffic from reaching its destination.
What is a DDoS attack and how does it work?
DDoS attack are carried out via networks of machines that are linked to the Internet.
These networks are made up of computers and other devices (such as IoT devices) that have been infected with malware, allowing an attacker to manage them remotely. Individual devices are known as bots (or zombies), while a network of bots is known as a botnet.
After establishing a botnet, the attacker can conduct an attack by sending remote commands to each bot.
When the botnet targets a victim’s server or network, each bot sends requests to the target’s IP address, potentially overloading the server or network and causing a denial-of-service to normal traffic.
Because each bot is a genuine Internet device, distinguishing between attack and normal traffic can be challenging.
How to Spot a DDoS Attack
The most visible indication of a DDoS attack is a site or service that becomes abruptly slow or unavailable. However, because a variety of causes, such as a legitimate spike in traffic, might result in identical performance concerns, further analysis is usually required. Some of these telltale signals of a DDoS attack can be detected using traffic analytics tools:
- Unusual quantities of traffic coming from a single IP address or IP range
- A flood of traffic from users with a common behavioral profile, such as device type, geography, or web browser version.
- An unexpected increase in the number of requests to a single page or destination
- Unusual traffic patterns, such as spikes at unusual times of day or patterns that appear to be abnormal (e.g. a spike every 10 minutes)
Other, more precise symptoms of a DDoS attack differ based on the sort of attack.
What are some of the most typical types of DDoS attacks?
DDoS attacks of various forms target different components of a network connection. To understand how various DDoS assaults work, it is crucial to first understand how a network connection is established.
A network link on the Internet is made up of numerous components or “layers.” Each layer in the model has a particular role, similar to how a house is built from the ground up.
The OSI model, depicted below, is a conceptual framework for describing network communication across seven distinct layers.
While nearly all DDoS assaults include flooding a target device or network with traffic, they can be classified into three types. In response to the target’s countermeasures, an attacker may utilize one or more alternative attack vectors, or cycle attack vectors.
Attacks on the application layer
The attack’s goal is:
The purpose of these attacks, sometimes referred to as layer 7 DDoS attacks (in reference to the 7th layer of the OSI model), is to exhaust the target’s resources in order to cause a denial-of-service.
The attacks target the layer on the server where web pages are created and delivered in response to HTTP requests. A single HTTP request is computationally cheap to execute on the client side, but it might be costly for the target server to respond to, because the server frequently loads numerous files and runs database queries to build a web page.
Layer 7 attacks are difficult to protect against since it can be difficult to distinguish between malicious and genuine traffic.
Example of an application layer attack:
This attack is analogous to repeatedly refreshing a web browser on multiple machines at the same time – massive amounts of HTTP requests flood the server, resulting in denial-of-service.
The complexity of this type of attack ranges from simple to sophisticated.
Simpler implementations may use the same range of attacking IP addresses, referrers, and user agents to reach the same URL. Complex variants may employ a huge number of attacking IP addresses and target random urls via random referrers and user agents.
Protocol attacks
The attack’s goal is:
Protocol assaults, also known as state-exhaustion attacks, disrupt service by consuming too much server resources and/or network equipment resources such as firewalls and load balancers.
Protocol attacks take use of flaws in the protocol stack’s layers 3 and 4 to render the target unreachable.
Example of a Protocol Attack:
SYN influx
A SYN Flood is akin to a supply room worker accepting requests from the front of the store.
The worker receives a request, goes to retrieve the package, and then waits for confirmation before delivering it out front. The worker then receives numerous further shipment requests without confirmation until they are unable to carry any more parcels, feel overwhelmed, and requests go unanswered.
This attack takes advantage of the TCP handshake — the series of contacts that two computers use to establish a network connection — by delivering a high number of TCP “Initial Connection Request” SYN packets to a target with spoofed source IP addresses.
The target computer answers to each connection request and then waits for the final step in the handshake, which never occurs, thus draining the target’s resources.
Volumetric attacks
The attack’s goal is:
This type of attack tries to cause congestion by absorbing all available bandwidth between the target and the rest of the Internet. Large amounts of data are transmitted to a destination via amplification or another method of creating massive traffic, such as botnet requests.
Example of amplification:
DNS Extensification
A DNS amplification is analogous to calling a restaurant and saying, “I’ll have one of everything, please call me back and repeat my entire order,” where the callback number belongs to the victim. A lengthy answer is generated and emailed to the victim with no effort.
The target IP address receives a response from the server after sending a request to an open DNS server with a faked IP address (the victim’s IP address).
What is the procedure for dealing with a DDoS attack?
The primary concern in mitigating a DDoS attack is distinguishing between attack and normal traffic.
For example, if a company’s website is inundated with excited customers as a result of a product launch, turning off all traffic is a bad idea. If the organization suddenly experiences a rise in traffic from known attackers, actions to mitigate an attack are likely to be required.
The challenge is distinguishing between legitimate clients and attack traffic.
DDoS traffic can take numerous forms on the modern Internet. The traffic can be designed in a variety of ways, ranging from un-spoofed single source attacks to intricate and adaptive multi-vector attacks.
A multi-vector DDoS attack employs numerous attack vectors to overwhelm a target in various ways, potentially confusing mitigation efforts on any one path.
A multi-vector DDoS assault is one that targets multiple layers of the protocol stack at the same time, such as DNS amplification (targeting layers 3/4) combined with an HTTP flood (targeting layer 7).
Mitigating a multi-vector DDoS attack necessitates a number of tactics to oppose various trajectories.
In general, the more complicated the attack, the more difficult it is to distinguish attack traffic from normal traffic – the attacker’s goal is to blend in as much as possible, making mitigation attempts as inefficient as possible.
Mitigation techniques that involve dropping or limiting traffic indiscriminately may mix in good and bad traffic, and the attack may also alter and adapt to avoid countermeasures. A layered approach will provide the most advantage in overcoming a complicated attempt at disruption.
Routing through a black hole
Creating a blackhole route and funneling traffic into it is one method available to almost all network administrators. When blackhole filtering is used without any restrictions, both valid and malicious network traffic is sent to a null route, or blackhole, and dropped from the network.
If an Internet property is under DDoS attack, the site’s Internet service provider (ISP) may divert all traffic through a blackhole as a protection. This is not a great option because it basically provides the attacker with their desired result: it renders the network unreachable.
Limiting the rate
Limiting the number of requests a server will take over a specific time period is another method of preventing denial-of-service attacks.
While rate limiting is useful for slowing down web scrapers and reducing brute force login attempts, it is likely insufficient to properly tackle a complicated DDoS attack.
Nonetheless, rate limiting is an important component of a successful DDoS mitigation scheme. Discover more about Cloudflare’s rate limitation.
Firewall for web applications
A Web Application Firewall (WAF) is a solution that can help prevent a layer 7 DDoS attack. When a WAF is placed between the Internet and an origin server, it can act as a reverse proxy, protecting the targeted server from certain types of harmful traffic.
Layer 7 attacks can be mitigated by filtering requests based on a set of rules used to identify DDoS tools. The ability to swiftly adopt custom rules in response to an attack is a crucial value of an effective WAF.
Diffusion of anycast networks
This mitigation strategy use an Anycast network to disperse attack traffic across a network of remote servers until it is absorbed by the network.
This strategy, similar to channeling a rushing river into smaller channels, distributes the impact of scattered attack traffic to the point where it becomes manageable, dispersing any disruptive capability.
The capacity of an Anycast network to mitigate a DDoS attack is dependent on the size of the attack as well as the network’s size and efficiency. The utilization of an Anycast distributed network is a key aspect of Cloudflare’s DDoS mitigation strategy.
techvibe. network has a capacity of 90 Tbps, which is an order of magnitude more than the greatest DDoS attack ever recorded.
If you are currently under attack, there are things you may take to relieve the stress. If you already use Cloudflare, you can reduce your assault by following these steps.
techvibe.org DDoS defense is complex in order to mitigate the numerous different attack vectors. Learn more about how Cloudflare’s DDoS prevention works.