The past two months have seen a number of healthcare organizations attacked by cybercriminals; however, the MedStar Health ransomware attack discovered on Monday this week must rank as one of the most severe.

The MedStar Health ransomware attack is the latest in a string of attacks on U.S. healthcare organizations, as hackers up the ante and go for much bigger targets where the potential rewards are greater. It would appear that the 10-hospital health system will not need to pay a ransom to regain access to its data, but for three days MedStar Health has been forced to work without access to some of its computer systems after they were shut down to prevent the spread of the infection.

MedStar Health Ransomware Attack Affects 10 Hospitals and More than 250 Outpatient Facilities

MedStar Health is a large U.S health system operating more than 250 outpatient facilities and ten hospitals in the Washington D.C., area. On Monday morning, a virus was discovered to have been installed. The infection triggered emergency IT procedures and rapid action taken to limit the spread of the virus. Three clinical information systems were shut down, including email and the electronic health record system used to record and view patient data.

Without access to email and patient data, services at the hospital were slowed although business continued as close to normal as possible. No facilities closed their door to patients. However, in the 48 hours since the virus was discovered, IT security teams have been working around the clock to bring systems back online. Yesterday, MedStar Health reported that systems were being brought back online with enhanced functionality added bit by bit.

MedStar Health has kept the media and patients notified of progress via social media. The health system reported that “The malicious malware attack has created many inconveniences and operational challenges for our patients and associates.”

While no information was initially released on the exact nature of the computer virus that was discovered to have infiltrated its systems, a number of sources indicate the malicious software was ransomware. It has since emerged that the MedStar Health ransomware attack involved a ransomware from the Samsam family. The ransomware is also known as MSIL and Samas. The attack occurred at the Union Memorial Hospital in Baltimore.

Some computer users were presented with a message demanding a ransom to unlock files. The Baltimore Sun reported that the MedStar Health ransomware attack saw attackers demand a ransom of 45 Bitcoin (approximately $18,500) to unlock all 18 computers that were infected, with an offer to unlock one machine for 3 Bitcoin (approximately $1233).

FBI Issued Warning About Samsam Ransomware on March 25

The FBI reached out to businesses for assistance dealing with the latest ransomware threat from Samsam. While many ransomware infections use email as the vector, Samsam is installed via a tool called JexBoss. JexBoss is used to discover a vulnerability that exists in JBOSS systems. This attack is not conducted using phishing or website exploit kits, instead it works by compromising servers and spreading the infection laterally.

The vulnerability exploited is in the default configuration of the Boss Management Console (JMX) which is used to control JBoss application servers. In its default state, JMX allows unsecured access from external parties and this is used to gain shell access to install the ransomware.

Once a web application server has been infected, the ransomware does not communicate with a command and control server, but will spread laterally and to infect Windows machines, hence the need to shut down systems. The MedStar Health ransomware attack could have been much more severe had rapid action not been taken.

This attack highlights just how important it is to ensure that all systems are patched and default software configurations are changed. Other attacks recently reported by healthcare organizations in the United States have involved Locky ransomware, which is spread via exploit kits on compromised websites and via email spam. Healthcare organizations can protect against those attacks by using web filtering and anti-spam solutions. However, it is also essential to train staff never to open email attachments from unknown sources.