Comcast Business 2021 DDoS Threat Report: DDoS Becomes a Bigger Priority as Multi-vector Attacks are on the Rise

Comcast Business mitigated 24,845 multi-vector DDoS attacks in 2021, a 47 percent increase over 2020

PHILADELPHIA – APRIL 20, 2022 – Comcast Business today published results from its 2021 Comcast Business DDoS Threat Report. The report provides an overview of the Distributed Denial of Service (DDoS) attack landscape, trends experienced by Comcast Business customers and insights for measuring and mitigating risks. The report found that mulit-vector DDoS attacks targeting Layers 3, 4, and 7 simultaneously represent a 47 percent increase from the record number set in 2020.

“DDoS attacks, when they occur, can be costly and difficult to defend. The risk of losing network, server and application availability is higher than ever,” said Shena Seneca Tharnish, Vice President, Cybersecurity Products, Comcast Business. “With threat actors constantly innovating, organizations must stay vigilant to help protect their infrastructure from bad actors determined to cause financial and reputational damage."

The report indicates that 2021 was another record year for DDoS attacks, as Comcast Business DDoS Mitigation Services successfully identified and helped defend 24,845 multi-vector attacks targeting Layers 3,4, and 7 simultaneously. Overall, 69 percent of Comcast Business customers experienced DDoS attacks, a 41 percent increase over 2020, while 55 percent were targets of mulit-vector attacks, as opposed to in 2020 where most customers experienced single vector attacks.

The data also shows that DDoS attackers were indiscriminate and persistent as no verticals were spared and everyone was fair game – from tow truck drivers to churches, government, utilities, IT companies, online gambling sites, and manufacturing operations. However, the healthcare and education sectors remain favorite targets.

Seventy-three percent of all multi-vector attacks targeted the education, finance, government and healthcare sectors, likely due to vulnerabilities brought on by the COVID-19 pandemic. Threat actors also used industry-specific seasonal trends and activities to guide attacks and maximize impact.

Attacks on education customers followed the cadence of a typical school year, starting strong in January before taking a significant dip over the summer when schools were out, while the financial sector experienced a 3X uptick in attacks during November and December compared to the rest of the year.

Other key findings from the 2021 Comcast Business DDoS Threat report include:

  • Attacks on information technology customers grew steadily, ending the year at 10X the January numbers.
  • 98 percent of all multi-vector attacks were under 5 Gbps, as bad actors often strike at low volumes to avoid detection, degrade site performance and map out network vulnerabilities for reconnaissance.
  • 69 percent of all multi-vector attacks lasted under 10 minutes, as short duration attacks are harder to detect and give IT organizations less time to respond, quickly overwhelming defenses.
  • The number of vectors deployed in a single multi-vector attack increased from five to 15, while the number of amplification protocols used in multi-vector attacks increased from three to nine.
  • 99 percent of customers experienced repeat attacks, while the largest and most severe attack was delivered at a rate of 242 Gbps.

The 2021 Comcast Business DDoS threat report focuses on multi-vector attacks that target Layers 3, 4, and 7 simultaneously. To download the report, please visit:

About Comcast Business
Comcast Business offers a suite of Connectivity, Communications, Networking, Cybersecurity, Wireless, and Managed Solutions to help organizations of different sizes prepare for what’s next. Powered by the nation’s largest Gig-speed broadband network, and backed by 24/7 customer support, Comcast Business is the nation’s largest cable provider to small and mid-size businesses and one of the leading service providers to the Enterprise market. Comcast Business has been consistently recognized by industry analysts and associations as a leader and innovator, and one of the fastest growing providers of Ethernet services.  

For more information, call 866-429-3085. Follow on Twitter @ComcastBusiness and on other social media networks at

About Comcast Corporation 

Comcast Corporation (Nasdaq: CMCSA) is a global media and technology company that connects people to moments that matter. We are principally focused on broadband, aggregation, and streaming with 57 million customer relationships across the United States and Europe. We deliver broadband, wireless, and video through our Xfinity, Comcast Business, and Sky brands; create, distribute, and stream leading entertainment, sports, and news through Universal Filmed Entertainment Group, Universal Studio Group, Sky Studios, the NBC and Telemundo broadcast networks, multiple cable networks, Peacock, NBCUniversal News Group, NBC Sports, Sky News, and Sky Sports; and provide memorable experiences at Universal Parks and Resorts in the United States and Asia. Visit for more information.

Media Contacts:

Matt Helmke, Corporate Communications
Comcast Corporation