Attackers Wrapping New Tools In Old Malware To Target Medical Devices

Medical devices running outdated operating systems like Windows XP and Windows 7 are giving attackers safe harbors within hospital networks for carrying out data theft in a nearly undetectable manner, a new report from TrapX Security warned this week.

The report is based on the security vendor’s analysis of data associated with an ongoing series of attacks against three healthcare institutions that are its customers. All of the attacks involve equipment running older, non-supported versions of Windows installed within the hospital networks.

The most significant takeaway from the analysis, according to TrapX, is the manner in which the attackers in each case intentionally repackaged and embedded sophisticated new malware tools in extremely old malware wrappers in an apparent bid to avoid detection.

One of the malware samples used in the attack, for instance, was designed to take advantage of a remote code execution vulnerability in Microsoft Server Service dating back to 2008. The attackers used the worm to compromise a radiation oncology system running Windows XP and a fluoroscopy workstation also running Windows XP in one of the hospitals. That access then allowed the attackers to install backdoors and botnet connections within the hospital network in order to exfiltrate data, though they could have easily caused significant damage to the equipment as well.

Since endpoints running newer Windows versions are not vulnerable to the threat, they did not either detect the malware or ignored it completely. “This ensured that the worm would go undetected while it sought out older Windows systems,” TrapX said in its report.

In another hospital, the attackers compromised a Windows XP-based MRI system and installed a Remote Access Trojan on the device using malware tools packaged inside an out-of-date wrapper for network32.kido.ib. The malware sample is ignored by patched Windows 7 and Windows 8 platforms and newer operating system and therefor managed to evade detection, the security vendor said.

According to TrapX, its analysis showed clear evidence that attackers are intentionally packaging their tools in a manner so to target medical equipment running Windows XP, Windows 7 and other older operating systems.

“The most interesting approach we discovered was the utilization of self-spreading malware that use old exploits that would compromise medical devices only,” says Moshe Ben-Simon, co-founder and vice president of services at TrapX.

Medical devices provide a tempting target for attackers because many of them run old, no-longer supported operating systems. So long as the equipment works as intended, hospitals are often reluctant to update the operating systems on these devices, Ben-Simon says

“Also, they are closed turnkey systems and hospitals are generally not allowed to install cyber defense software on them because of legal and risk issues.” Unlike typical desktop systems, medical devices do not get updated often and some equipment can remain in place for years after their operating systems have become obsolete. As a result, the corrections and fixes that are available on newer operating systems are not present in these medical devices making them vulnerable to attacks, Ben-Simon says.

Even when an organization makes the effort to keep their systems patched, all it takes for an attacker to break into them is to repackage the malware slightly using easily available tools.

“Once a backdoor is established in one machine, they can move into other machines under the control of the human attacker,” Ben-Simon says. “These medical devices create a huge series of safe harbors within the hospital network, not easily detected, and very difficult to remediate and remove.”

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