The cybercriminal organization behind Ryuk ransomware – believed to be an eastern European hacking group known as Wizard Spider – has stepped up attacks on hospitals and health systems in the United States. This week has seen a wave of attacks on hospitals from the Californian coast to the eastern seaboard, with 6 Ryuk ransomware attacks on hospitals reported in a single day.
Ryuk ransomware causes widespread file encryption across entire networks, crippling systems and preventing clinicians from accessing patient data. Even when the attacks are detected quickly, systems must be shut down to prevent the spread of the ransomware. While hospitals have disaster protocols for exactly this kind of scenario and patient data can be recorded using pen and paper, the disruption caused is considerable. Non-essential surgeries and appointments often need to be cancelled and, in some cases, hospitals have been forced to divert patients to alternative medical facilities.
It is unclear if any ransomware attacks on U.S. hospitals have resulted in fatalities, but there was recently a fatality in an attack in Germany, where a patient was rerouted to a different hospital and died before lifesaving treatment could be provided. Had the ransomware attack not occurred, treatment could have been provided in time to save the patient’s life. The attacks in the United States also have the potential to result in loss of life, especially in such as large-scale, coordinated campaign.
Earlier in the week, the U.S. Cybersecurity and Infrastructure Security Agency (CISA), the FBI, and the Department of Health and Human Services (HHS) issued an advisory after credible evidence emerged indicating Ryuk ransomware attacks on U.S. hospitals and healthcare providers were about to increase.
It is unclear why the attacks have increased now and the exact motives behind the current campaign, but recently Microsoft and U.S. Cyber Command, in conjunction with several cybersecurity firms, disrupted the TrickBot botnet – A network of devices infected with the TrickBot Trojan. The TrickBot Trojan is operated by a different cybercriminal group to Ryuk, but it was extensively used to deliver Ryuk ransomware. The botnet is back up and running, with the threat actors switching to alternative infrastructure, but there have been suggestions that this could be a response to the takedown.
The Ryuk ransomware attacks on hospitals come at a time when healthcare providers are battling the coronavirus pandemic. In the United States the number of new cases is higher than at any time since the start of the pandemic. Hospitals cannot afford to have systems taken out of action and patient care disrupted. The timing of the attacks is such that hospitals may feel there is little alternative other than paying the ransom to ensure that disruption is kept to a minimum. Ransomware gangs are known to time their attacks to cause maximum disruption.
Ryuk ransomware attacks on hospitals have been steadily increasing in the United States prior to the latest spike. Figures released by Check Point Research in the past few days show ransomware attacks on hospitals increased 71% from September, with healthcare the most targeted industry sector, not only in October, but also Q3, 2020. Ryuk ransomware attacks account for 75% of all ransomware attacks on hospitals in the United States.
There is concern that the latest attacks will be just the tip of the iceberg. Some security experts suggest the gang is looking to target hundreds of hospitals and health systems in the United States in this campaign. Each attack on a health system could see several hospitals affected. The attack this week on the University of Vermont Health Network impacted 7 hospitals.
Defending against ransomware attacks can be a challenge, as multiple methods are used to gain access to healthcare networks. Ryuk ransomware is commonly delivered by the TrickBot Trojan, which is delivered as a secondary payload by the Emotet Trojan. The Buer loader and BazarLoader are also being used to deliver Ryuk ransomware. These malware downloaders are delivered via phishing emails so a good spam filter is therefore important.
Employees should be made aware of the increased threat of attack and advised to exercise extra caution with emails. Software updates need to be applied promptly and all systems kept fully patched and up to date. Default passwords should be changed, and complex passwords used, with multi-factor authentication implemented where possible. If it is not necessary for systems to be connected to the Internet, they should be disconnected, and RDP should be disabled where possible.
It is also essential for regular backups of critical data to be made and for those backups to be stored securely on non-networked devices to ensure that in the event of an attack hospitals have the option to recover their data without having to pay the ransom.
Further information on indicators of compromise and other mitigations are available in the CISA Ryuk ransomware advisory.