DDoS attacks are common nowadays—the most recently known being the 1.3Tbps DDoS attack on GitHub in 2018. Botnets are the primary causal agents of a DDoS attack. They accomplish this by hitting a server with voluminous traffic that its bandwidth cannot withstand. Before focusing on the various mitigation techniques to layer 7 DDoS attacks, let us consider two factors that make it hard to defend against layer 7 DDoS attacks.
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Factors that exacerbate effective defense buildup against layer 7 DDoS attacks
Lack or minimal knowledge on the matter
Some IT experts are inexperienced on this matter. Therefore, they end up making inappropriate and dubious measures for protection against the attack. When dealing with application-layer DDoS, over-provisioning the bandwidth is not effective.
Low budgets and rushes to completion of application developments
Application development is often hectic, especially when the developer is in a hurry to finish. It does not leave much time for the developer to conduct tests to know where the issues may lie. The other issue is low budgets that do not provide room for better application development methods and the installation of security mechanisms. Therefore, the quality of the application delivered by the developer has defects.
The above factors combined with several others lead to weak applications that the attackers exploit to the detriment of the application owner.
Detection of layer 7 DDoS attacks
Detecting layer 7 attacks is difficult because of a range of factors. Let us consider the factors that make it hard to detect layer 7 DDoS attacks.
- TCP anomaly can not detect application layer attacks through HTTP requests because there can be a successful TCP connection.
- Since Network DDoS detection techniques belong to another type of layer, they cannot successfully detect layer 7 DDoS attacks.
- To establish a TCP connection, you require a legit Ip address and packets of IP. It effectively handicaps the detection of anomalies.
- Because layer 7 DDoS attacks look like regular web traffic, their traffic is minimal, and they mimic the behavior of an actual user.
How can you distinguish between real traffic and layer 7 DDoS attacks?
The key to unlocking or detecting a layer 7 attack is distinguishing between malicious requests and legitimate traffic. When you differentiate two correctly, you can make a positive DDoS detection. Hence, you can take the proper mitigation measures. Usually, you can start comprehensive monitoring of traffic based on pre-defined behavior profiles for the traffic. You create these profiles from repeated measures of website interactions that are stored and shaped as statistical data.
These measures include:
Every server can collect and follow the information that belongs to several units of measure. These units are called statistical attributes. These attributes include:
Uptime and downtime
Uptime refers to the duration that a user has a connection to the server until they end the connection. The interval that a user is in latent mode until they connect to the server. To fill out the profiles and determine if it is a DDoS attack or legitimate traffic, statistical data showing the length of the session, the dissemination of frequency of the TCP flags is helpful.
Request and download rate
The other pointer to differentiate between a DDoS attack and legitimate user traffic is by monitoring the number of bytes a user has downloaded within a time interval.
The other statistical attribute that can be used in differentiating between the traffic is the browsing behaviors. This value depends on the behavior of the users and the structure of the website. Therefore, it is crucial to look at the page’s popularity when you are performing the evaluations.
Services and equipment for layer 7 DDoS mitigation
Installing a firewall on your computer system is an effective way of preventing intrusion. Through such, the probability of a DDoS attack happening becomes minimal. To effectively mitigate DDoS attacks, a process or software should be capable of tracking and analyzing all the sessions. Because we deploy them near the server, they can suffer resource exhaustion. Firewalls like IPS and IDPS open a new connection on their connection table for every malicious packet that can cause a DDoS attack.
Bot management solution
As we figured out above, the causal agent for most DDoS attacks is the botnet. Hence, when you invest in a bot protection mechanism, you can effectively block any layer 7 DDoS attacks that can come your way. Such tools use the latest technologies like artificial intelligence, behavioral analysis, and machine learning for real-time detection and layer 7 DDoS attack mitigation.
How can you mitigate specific layer 7 DDoS attacks?
HTTP POST DDOS
You can enforce rate limiting through classification and monitoring each request’s speed, performance, and size. If there are extremely slow connections within each CPU or above the highest allowed, their amount should be limited.
Low orbit ion cannon (LOIC) is a tool that attackers use to effect layer 7 DDoS attacks. Its users have to use anonymizers because it passes on a user’s actual IP address. Therefore, as a mitigating option, you can block all the nodes associated with anonymization, for instance, TOR. This blocks other attacks besides the. Because they can reuse the Mobile LIOC page, ensure that you have a list of referrers who are malicious.
We know this type of DDoS attack has a long period between the headers and has low rates. You can counter Slowloris by switching to a server platform based on Microsoft and using load balancers. Under normal circumstances, for instance, Microsoft IIS is not vulnerable to attacks from Slowloris.
HTTP GET DDOS
Servers with timeout limits for HTTP headers like MS IIS web servers are usually not prone to GET DDoS attacks. Using apache modules like mod_antiloris and other measures like reverse proxies and the load balancer usually thwart these attacks. Other workable alternatives are TCP splicing or delayed binding.
Despite all the above measures for detecting and mitigating layer 7 DDoS attacks, there is no universal way of mitigating the attack. We recommend a combination of several measures enumerated above to ensure favorable results. It is crucial, depending on your needs to enlist for a bot mitigation solution. They stop various botnet-caused DDoS attacks and other forms of bot-caused attacks from affecting your online infrastructure.