Suspected North Korean hackers have recently tried to break into at least nine health organizations, including pharmaceutical giant Johnson & Johnson and vaccine developer Novavax Inc, revealing a broader effort to target key players in the race to develop treatments for Covid-19.
Four people who have investigated the attacks said the spate of hacking attempts began in September and used web domains mimicking online login portals to try and trick staff at the targeted organisations into revealing their passwords.
The hacking attempts included a bid to get inside British drugmaker and vaccine developer AstraZeneca, which Reuters first reported last week was in Pyongyang's crosshairs.
North Korea has not confirmed any coronavirus infections, but South Korea's National Intelligence Service has said an outbreak there cannot be ruled out as the country had trade and people-to-people exchanges with China - the source of the pandemic - before shutting the border in late January.
A Reuters review of publicly-available Internet records shows that web domains and servers used by the attackers have previously been identified by the US government and security researchers as part of a North Korean hacking campaign.
Other targets identified by the sources, most of whom spoke on condition of anonymity due to the sensitivity of the matter, including the Beth Israel Deaconess Medical Center in Boston, the University of Tuebingen in Germany, and four South Korean pharmaceutical firms: Genexine Inc, Boryung Pharma Co Ltd, Shin Poong Pharm Co Ltd and Celltrion Inc.
Reuters was not able to determine if any of the hacking attempts, some of which were reported by the Wall Street Journal earlier on Wednesday, were successful.
North Korea's mission to the United Nations in New York did not immediately respond to a request for comment. A message sent to an email address used by the hackers was not returned. Pyongyang, which has no direct line of contact for foreign media, has previously denied carrying out cyberattacks.
Novavax spokeswoman Amy Speak said her company was "aware of this threat" and was coordinating with government agencies and private cybersecurity experts.
"We are confident we can continue to progress with our Covid-19 vaccine candidate without disruption and that these incursions do not pose a risk to the integrity of our data," she said.
A spokeswoman for the University of Tuebingen said staff were repeatedly targeted by hackers but all recent attacks "were detected and blocked by our IT-Team at a very early stage, no damage occurred."
Genexine said it was aware of a malicious website impersonating a company login portal but had not recorded any direct attacks against its staff. Celltrion said it had recently identified and successfully blocked a number of hacking attempts as part of its regular security work.
Johnson & Johnson, Beth Israel, and Shin Poong declined to comment. Boryung did not immediately respond to a request for comment.
Simon Choi, an expert at South Korean cybersecurity group IssueMakersLab, said he had attributed the hacking attempts to North Korea and it was clear the attackers were specifically hunting for information about Covid-19.
In the case of South Korea's Celltrion, for example, he said the spies tried to break into an email account set up to field queries about Remsima, a monoclonal antibody which is being studied as a treatment for severe cases of the disease.
A person familiar with the matter said that some of the fake login pages had been spotted by security experts at Microsoft Corp, helping prompt an alert the company issued last month about the threat of North Korean espionage to Covid-19 researchers.
Microsoft stopped short of naming the targeted organizations in its Nov. 13 blog post but said they were "leading pharmaceutical companies and vaccine researchers" in countries including the United States and South Korea.
Lawmakers in South Korea also appear to have alluded to the digital espionage campaign, saying last week that its intelligence service thwarted attempts by Pyongyang to hack into South Korean companies developing coronavirus vaccines, although they provided no further details.
Officially, North Korean authorities have reported no cases of coronavirus in their country, making it the only non-island nation - aside from Turkmenistan - to do so. But North Korean leader Kim Jong Un raised eyebrows last month when he was quoted by state media as ordering officials to intensify their anti-coronavirus work.
Digital espionage against health bodies, vaccine scientists and drugmakers has intensified during the Covid-19 pandemic as state-backed hacking groups scramble to obtain the latest research and information about the outbreak.
Reuters has previously documented how hackers linked to Iran, Vietnam, South Korea, China and Russia have on separate occasions been accused of trying to steal information about the virus and its potential treatments.
Western officials say any stolen information could give foreign governments a valuable strategic advantage as they fight to contain the disease.