Researchers at TrapX have observed several hospital attacks where malicious actors disguised their sophisticated tools as old pieces of malware in an effort to avoid detection.
Last year, the security firm published a report detailing medical device hijacking, or Medjack, attacks. Experts described several operations that went undetected for months after attackers leveraged medical devices found in the targeted hospital’s network as key pivot points.
In a report published on Monday, the company described three new Medjack attacks where attackers used malware specifically designed to target old and unpatched versions of Windows, which often run on medical devices. In these operations, malicious actors packaged new and highly sophisticated tools in old and outdated pieces of malware.
Since medical devices running old versions of Windows often don’t have any additional protections, and since the malware had not targeted any newer Windows releases that might detect malicious activity, the attackers could operate for extended periods of time without raising suspicion.
One of the attacks observed by TrapX targeted a top 1,000 global hospital that had a centralized intrusion detection system (IDS), endpoint protection and next generation firewalls. Researchers discovered backdoors in radiation oncology, respiratory gating and fluoroscopy systems running Windows XP.
The attacker’s sophisticated tools, which allowed them to move between networks, were hidden inside an old variant of the notorious Conficker worm.
A different attack targeted a hospital’s picture archiving and communication system (PACS). The organization had been using IDS, firewalls and endpoint security products, but attackers managed to compromise the PACS network in search for vulnerable medical devices.
This threat actor also wrapped its sophisticated malware in an old version of the Conficker worm. The worm ignored patched Windows 7 and Windows 8 systems, and turned its attention to Windows XP machines, which it infected with a remote access tool (RAT).
The cybercriminals planted a backdoor on an MRI system and it took the hospital several weeks to remediate the attack due to the device being located in the urgent care unit.
In the third attack analyzed by the security firm, cybercriminals targeted a top 10,000 global hospital. The threat actor had managed to compromise an X-ray device using a piece of malware that was also wrapped inside an outdated worm.
“These old malware wrappers are bypassing modern endpoint solutions as the targeted vulnerabilities have long since been closed at the operating system level. So now the attackers, without generating any alert, can distribute their most sophisticated toolkits and establish backdoors within major healthcare institutions, completely without warning or alert,” TrapX said in its report. “Attackers have put considerable research and development into these new tools. This advanced malware can now hop laterally across networks to exploit virtually any information within the healthcare institution.”
Researchers believe that while they could have tampered with the operation of the infected medical devices, the attackers apparently focused on the theft of patient data, which can be highly valuable on the black market. The cybercriminals could have also leveraged the access to install ransomware – such attacks have been increasingly common in the past months.
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