Largest DDoS Attack by Packet Volume Unleashed

Largest DDoS Attack by Packet Volume Unleashed

Cybersecurity software company Imperva recently uncovered the largest distributed denial-of-service (DDoS) attack by packet volume.

According to Imperva, in early January, this year, the company’s DDoS protection service mitigated a DDoS attack against one of its clients which unleashed more than 500 million packets per second. This DDoS attack unleashed the most packets per second ever recorded.

What Is Packets Per Second (PPS)?

Packets per second (PPS) measures the forwarding rate – referring to the number of network packets that can be processed by networking equipment such as a router. Forwarding rate is often confused with throughput rate, also known as bandwidth.

Throughput rate refers to the amount of data that can travel through your internet connection. While forwarding rate is measured by PPS, throughput rate is measured by bits per second (bps) or Gigabits per second (Gbps).

In layman’s terms, throughput rate can be likened to the weight capacity of an elevator, while the forwarding rate can be likened to the maximum number of people permitted inside the elevator. Similar to humans, network packets come in different sizes and shapes. Similar to the difficulty of knowing how many people will fit into an elevator due to the differences in sizes and shapes, there are no real means of knowing how many network packets make a gigabit.

Protocol DDoS Attacks versus Volumetric DDoS Attacks

For years, DDoS protection service providers and clients have focused on throughput attacks, also known as volumetric DDoS attacks or bandwidth-intensive attacks. Forwarding attacks, also known as protocol DDoS attacks or PPS attacks, meanwhile, are given less attention.

Protocol DDoS Attacks 

Protocol DDoS attack is a type of attack that goes after server resources directly. This type of attack is measured by packets per second (PPS). If the packets-per-second rate is large enough, the server will crash.

One of the ways by which attackers crash servers in a protocol DDoS attack is through syn flood. In a syn flood DDoS, an attacker exploits part of the normal TCP three-way handshake, consuming resources on the targeted server and rendering it unresponsive.

TCP, which stands for transmission control protocol, refers to the protocol which defines how computers send packets of data to each other. The attacker in syn flood DDoS sends TCP connection requests faster than the targeted computer can process them, causing network saturation.

According to Imperva, the syn flood DDoS that the company’s DDoS protection service mitigated in early January, this year was “augmented by a large syn flood (packets of 800-900 bytes)”. Imperva added, “The source ports and addresses of the traffic sent to our customer’s server were highly randomized and probably spoofed.”

Volumetric DDoS Attacks

In a volumetric DDoS attack, an attacker sends voluminous traffic to a site to overwhelm its bandwidth. The DDoS attacks proliferated by Mirai are examples of volumetric DDoS attacks.

Mirai is a malicious software (malware) that infects computers, in particular, internet of things (IoT) devices such as routers, using factory default login and password combinations. The first version of Mirai infected hundreds of thousands of IoT devices using factory default login and password combinations.

Once infected with Mirai malware, these compromised IoT devices are then turned into a botnet – an army of infected IoT devices controlled by an attacker or attackers to conduct malicious activities such as DDoS attacks. The creator of Mirai made the source code of this malware publicly available, enabling others to use this malware for their own means.

According to the UK National Crime Agency (NCA), Daniel Kaye from Egham, Surrey operated his own Mirai botnet, composed of a network of infected Dahua security cameras, to carry out DDoS attacks on Lonestar, the largest Liberian internet provider. The NCA said that the traffic from Kaye’s Mirai botnet was so high in volume that it disabled internet access all over Liberia in November 2016. A UK court recently sentenced Kay to 2 years and 8 months for this cybercrime.

Another way by which attackers launch volumetric DDoS attack is through memcached – a database caching system for speeding up websites and networks. Memcached isn’t supposed to be exposed to the public internet. Arbor Networks, however, reported on February 27, 2018 that many memcached had been deployed worldwide with no authentication protection, leaving them vulnerable for attackers to exploit.

On February 28, 2018, popular code repository GitHubreported that its site was unavailable for few minutes as a result of a memcached-based DDoS attack which peaked at 1.35Tbps via 126.9 million packets per second.

Memcached attack works by sending spoofed requests to vulnerable servers. These vulnerable servers then respond with a larger amount of data than the spoofed requests, magnifying the volume of traffic.

Unlike Mirai which needs to infect vulnerable devices, DDoS attacks using the memcached approach only need to spoof the IP address of their victim and send small queries to multiple memcached servers. According to Akamai, memcached can have an amplification factor of over 500,000, which means that a 203 byte request results in a 100 megabyte response.

How to Prevent DDoS Attacks

While PPS and bandwidth-intensive DDoS attacks are both highly destructive or damaging to victims, in terms of mitigation, these two differ.

In the case of the GitHub DDoS attack, while it was considered as the largest DDoS attack ever at the time, which peaked at 1.35Tbps; the unleashed packets per second, meanwhile, was only 126.9 million – 4 times lesser than the volume of packets in the recent DDoS attack uncovered by Imperva.

"For a DDoS protection or mitigation service, mitigating a high PPS attack can be its Achilles heel, while a bandwidth-intensive attack can be much easier to handle, even with hundreds of gigabits per second, if it is composed of a smaller number of large-sized packets,” Imperva said.

The Driz Group is Imperva’s partner and can help your organization to mitigate DDoS attacks in a matter of minutes. Contact ustoday and protect your infrastructure and sensitive information.