Top eight DDoS attacks that organisations must avoid

Malware perils lurk in all directions, with DDoS attacks high on the danger list. According to a recent company report, the number of DDoS attacks increased by 37%, while DDoS attack volumes increased 26% between 2020 and 2021. In fact, early this year, Microsoft disclosed the largest DDoS attack ever recorded at 3.47Tbps.

Not only are DDoS attacks on the rise, but they are as diverse as they are sophisticated. They are weaponised as part of nation-state attacks and cyber warfare strategies; used by hacktivists to attract publicity for their political points of view; engineered by students to get out of final exams; and carefully disguised to fly under the radar, tricking even the biggest cloud providers.

To make matters even more complicated, attackers can now wreak havoc with little or no knowledge of networks and cyber attacks. Supported by an escalating array of online marketplaces, attack tools and services are easy to access, making the pool of possible assaults larger than ever.

As a result, it's more crucially important than ever to ensure that organisations' DDoS mitigation solutions provide comprehensive protection from a broad array of DDoS assaults.

Here are eight of the most common and sophisticated DDoS attacks that businesses should be prepared to stop.

#1 Burst attacks and advanced persistent denial-of-service (APDoS) campaigns include short bursts of high-volume attacks lasting 15-60 seconds at random intervals as well as attacks that can last weeks, involving multiple vectors aimed at all network layers simultaneously. This type of attack tends to cause frequent disruptions to network performance and SLAs, preventing legitimate users from accessing services.

Because attack vectors can change across individual bursts, signatures need to be constantly adapted — a process that can be labour intensive if not infeasible. A behavioural-based DDoS protection technology that utilises machine learning algorithms is required to adequately defend against burst attacks.

#2 DNS attacks are exploits in which an attacker takes advantage of vulnerabilities in a domain name system (DNS), a service run by third parties and therefore more difficult to protect than an organisation's assets. DNS attacks remain highly attractive to attackers as they require relatively few resources and can not only cause severe damage to DNS critical infrastructure but also threaten and cause outages for customers that rely on that infrastructure.

Because when there is no DNS, there is no service. Sophisticated attackers use DNS protocol weaknesses to generate more powerful attacks, including DNS water torture and DNS recursive attacks. Mitigating these attacks requires tools to learn and gain a deep knowledge of DNS traffic behaviour.

#3 Dynamic content and CDN-based attacks are insidious. Organisations use content delivery network (CDN) providers to support global site and application performance. Unfortunately, CDNs provide a particularly dangerous cover for attacks, as organisations cannot block traffic coming from the CDN's IP addresses.

Malicious actors have made an art form out of spoofing IP addresses to obfuscate their identity and masquerade as seemingly legitimate users based on geolocation or positive reputational information about the IP addresses they can compromise. Dynamic content attacks further exploit CDN-based protection by overloading origin servers with requests for noncached content that the CDN nodes simply pass along.

# 4 SSL/TLS and encrypted attacks use SSL protocols to mask and further complicate attack traffic in both network and application-level threats. Many security solutions use a passive engine for SSL attack protection, meaning they cannot effectively differentiate encrypted attack traffic from legitimate encrypted traffic while only limiting the rate of request.

# 5 IoT botnets can be helpful or otherwise. While robotic process automation and other good bots help accelerate productivity and business processes, such as data collection and decision-making, malicious bots can create a large-scale DDoS attack on your network and services. Organisations continue to rely on conventional security solutions to assess bot traffic, but today's sophisticated bad bots can mimic human behaviour and bypass CAPTCHAs and other older technologies and heuristics.

# 6 Layer 7 application DoS attacks target resource exhaustion by using the well-known Hypertext Transfer Protocol (HTTP) and HTTPS, SMTP, FTP, VOIP and other application protocols that possess exploitable weaknesses, allowing for DoS attacks. Much like attacks targeting network resources, attacks targeting application resources come in various flavours, including floods and 'low and slow' attacks.

# 7 Ransom DDoS attacks involve perpetrators who send an email threatening to attack an organisation, rendering its business, operations or capability unavailable unless a ransom is paid by the deadline. The number of these attacks is growing annually and typically takes the form of a volumetric DDoS attack. RDoS attacks are particularly insidious because they do not require the attacker to hack into the target's network or applications.

# 8 Reflection/amplification attacks take advantage of a disparity of request and response ratios in certain technical protocols. The attackers send packets to the reflector servers with a source IP address spoofed to their victim's IP, indirectly overwhelming the victim with the response packets.

At high rates, these responses have generated some of the largest volumetric DDoS attacks to date. A common example is a reflective DNS response attack.

Defending an organisation against these eight types of attack requires DDoS mitigation that combines automated, machine-learning based detection and mitigation capabilities with comprehensive protection for any infrastructure — on-premise, private cloud, and public cloud.