Newly published telemetry data collected by the researchers at Bitdefender suggests that U.S. reports of coronavirus-themed malware threat activity have been heaviest in states where testing has increased and the total number of confirmed infections has grown.

Among U.S. states, California reported the most threats in both March and April, followed by Texas. New York was third in March, but fell to fourth in April, supplanted by Florida. Ohio rounded out the top five.

These highly affected states are home to large populations, so it is not entirely surprising they would be subjected to larger numbers of COVID-19 incidents. Still, Bitdefender found the observation noteworthy.

"...[W]e noticed a correlation between the total number of new coronavirus tests for each state and our coronavirus-themed malware telemetry. It may or may not be a coincidence," states a Bitdefender blog post report authored by Senior Cybersecurity Analyst Liviu Arsene. "But we can safely infer that people who get tested are interested in learning more about potential treatments, medicine, medical best practices and maybe even other patients' experiences. Therefore, those spending more time online looking for information about COVID-19 are more likely to fall prey to scams and malware related to coronavirus."

Overall, reports of coronavirus-themed cyber threats increased from March to April, the report continued, with the U.S. leading among the most affected countries and retail tops among the most targeted industries.

After the U.S., the countries next most affected by COVID-19 cyber threats in April (based on unique IP addresses) were South Africa, Italy, Canada and the UK. In March, the top five fell in this order: the U.S., Italy, the UK, Spain and South Africa.

"Countries that have reported the largest number of coronavirus-themed reports seem to have also been those hit hardest by the pandemic," concludes Arsene.

Over March and April, retail has been the sector most targeted by COVID-19 threats, according to Bitdefender, followed by transportation and manufacturing. Health care did not make the top 10 of impacted sectors.

"While the number of attacks against health care has definitely increased during the pandemic compared to what they traditionally used to be, it cannot compete in terms of sheer numbers and volume" of the other industries," wrote Arsene.

COVID-19-linked threat reports observed by Bitdefender telemetry peaked on March 18 and 19, with a total of 14,350 reports and 10516 reports on those two days, respectively. Then from March 20 through April 18, the number of reports fluctuated anywhere from the low thousands to as high as nearly 7,000.

Bitdefender found that more reports tend to flow in during the the work week, then things slow down on weekends.