How to Detect DDoS Attacks?

September 9, 2022

7 Min Read

Cybersecurity has been a worldwide threat, and DDoS attacks remain a major concern. Infotech-driven businesses, small companies, and mega corporations are all potential targets of such cyberattacks, which can bring operations to a screeching halt.

What is a DDoS attack?

It’s a cyberattack aimed at overwhelming a server with malicious traffic, causing a website to shut down temporarily or permanently.

It’s typically executed using malware-infected devices called bots, and their cluster is referred to as a botnet. These bots include laptops, smartphones, smart TVs, wearable devices, thermometers, security cameras, in-vehicle infotainment systems, etc.

So, what industries do DDoS attackers target? They commonly target the gaming, software and technology, media and entertainment, finance, and internet and telecom industries.

Some popular tools used during a DDoS attack include LOIC, HULK, Tor’s Hammer, RUDY, DDoSISM, Slowloris, Golden Eye, and HOK.

Early and Accurate Detection is Key

Early detection and traffic monitoring are critical in DDoS attack prevention. You can manage, monitor, and filter malicious traffic, requests, and data packets through smart scanning programs and firewalls.

A firewall is a network security element used to refine incoming and outgoing network traffic according to the security standards and protocols selected.

It’ll help you automatically or manually distinguish between normal and dangerous requests based on behaviours, patterns, and signature analysis. Moreover, these intelligent tools allow you to block malicious requests, averting DDoS attacks.

These days firewalls are powered by artificial intelligence to scan vulnerabilities and remediate them in the first place. However, DDoS attack detection techniques extend far beyond firewalls alone.

DDoS Attack Indicators

You should be aware of the following indicators to identify a DDoS attack. You can use these signals to automate DDoS attack detection tools for timeous notifications.

Too Many Unexpected Requests for a Particular IP

This indicator can be used to temporarily command your router to send traffic to blackhole routes from a certain IP address. A blackhole is a network spot where incoming or outgoing traffic is disposed of.

Directing the router will take an attacking IP to a dead-end, thus protecting your servers. However, this isn’t recommended, as you’ll block any non-malicious traffic.

With this indicator, you can’t set alerts on DDoS attack prevention and detection programs as they’ll highlight legitimate bots too.

So, how can you stop different types of DDoS attacks by detecting unusual traffic? The answer is simple: You can set alerts for when a particular IP address sends too many requests within a short time. This works best with the allow listing method as there’ll be exceptions like Google bots.

Server Displaying ‘Error 503’

The HTTP Error 503 indicates that a website’s server is unavailable or unable to handle any requests, which could be due to a DDoS attack.

You can set up alerts whenever a certain event takes place. In Windows, you can do this in the Event Viewer. Attach a task to any event deemed worthy of investigating, such as ‘Error 503.’

An issue can be attached in two simple steps:

Open Event Viewer and right-click on the event.
A configuration screen will open. Fill in the columns to send notification emails to selected personnel.

TTL Times Out

TTL is short for Time to Live—the time a packet is set to exist in a network before a router repudiates it. You can automate ping alerts, and several service providers do that. This way, your website will be monitored around the clock. Ping time is the duration taken by small datasets to be transmitted from a device to a server.

This works on the principle that DDoS or DoS attacks consume undue bandwidth, so the ping time will be too long or time out altogether.

In-Line vs. Out-Of-Band Monitoring

In-line packet examination and out-of-band monitoring are DDoS attack detection methods for both cloud and on-premises.

Once you know how a DDoS attack works, you can use tools placed in the main data path, called in-line, or set outside the path, called out-of-band. Let’s learn more about these detection techniques.

In-Line DDoS Protection

In-line DDoS protection tools work within the data center or in-line as a DDoS attack prevention and detection layer set up above your infrastructure.

Such tools monitor affected and unaffected traffic where malicious requests are filtered, allowing only incoming and outgoing legitimate traffic.

The tools learn standard traffic patterns, thereby detecting abnormal activities.

Advantages of In-Line DDoS Protection Tools

Quickly detects malicious traffic, mitigating an attack.
No indeterminate network hiccups.
Uses learning mechanisms to self-adjust to protection configurations.
Knows how to identify a DDoS attack that isn’t based on volumes.
No extra hardware like flow analyzers and BGP tools are required.
This DDoS attack detection technique can use real Layer 7 security services.

Disadvantages of In-Line DDoS Protection

High possibility of false positives with abnormal IP use.
Increased latency.

Out-of-Band DDoS Protection

Out-of-band tools passively process packet data to evaluate certain aspects of live data streams. IDS, or Intrusion Detection System, is an out-of-band protection tool for monitoring and filtering traffic.

Advantages of Out-of-Band DDoS Protection

It can be used to detect and avert volume-based attacks.
No increased latency in un-attack mode as the traffic isn’t inspected.
Low probability of false alarms.

Disadvantages of Out-of-Band DDoS Protection

Slow detection.
Mitigation takes time due to indeterminate network hiccups.
It can’t automatically adjust to the protection configuration.
Slow Layer 7 security services aren’t possible.
Requires additional hardware like analyzers and BGP tools.

More Tips

Compared to 2020, 2021 saw an uptick of 11% in the number of DDoS attacks, reaching almost 5.4 million. Data like this makes it even more important to understand what motivates DDoS attacks and how to detect them timeously.

Here are some more useful tips on how to identify a DDoS attack.

Web Scanners, WAF, and Traffic Anomaly Detection

Web scanners, web application firewall (WAF), and traffic anomaly DDoS attack detection tools can help reduce damage and traffic profiling. Web scanners monitor web applications regularly, especially after an attack, while WAF filters traffic using machine learning algorithms.

They work by noticing unusual activities, identifying and blocking bots, and sending the data to a scrubbing centre for analysis and further action.

Build DDoS Detection Into Your Infrastructure

Your IT structure must be backed up by a robust shield, averting volumetric and protocol DDoS attacks. Never ignore any software updates as they may contain code capable of combating new techniques used by threat actors.

DDoS-resilient infrastructure manages excessive traffic when a server is hit. Such solutions can direct traffic to scrubbing centres to check network requests, filter legitimate traffic, and apply rules and policies to mitigate future attacks.

Summary

DDoS attacks overwhelm servers with malicious traffic, causing a website to shut down temporarily or permanently. Companies can prevent and detect such threats using in-line or out-of-band protection tools.

You can also set alerts for too many unexpected requests from a specific server. In this scenario, they can start filtering the malicious requests using tools.

Web scanners and firewalls can help mitigate the after-effects of an attack or even prevent one in the first place. They can observe unusual network-related activities and generate alerts too.

A DDoS-resilient infrastructure and the right DDoS attack detection tools can mitigate such attacks effectively.