Unfortunately, this seemingly positive trend does not reflect the actual threat landscape in the healthcare industry. Healthcare organizations subject to HIPAA only need to report breaches to HHS if 500 or more patient records are exposed. Many types of cyberattacks on hospitals, like ransomware, impact systems and possibly patient care, but do not result in breached records and hence are not reported to HHS (although there are currently opposing views on whether a ransomware attack should be reportable under HIPAA).
Ransomware is a type of malware that restricts access to files or systems with encryption until the victim (the hospital) pays the ransom for the key to unlock them. In a previous post I outlinedhow hospitals can track down the infected PC when an infected PC somewhere on the network encrypts the contents of an entire department shared drive.
As a former security operations lead for a hospital network, I responded to numerous ransomware infections firsthand as a result of targeted phishing campaigns against the hospital. The incident response team followed the same procedure for each incident: isolate the infected PC and restore the corrupted (encrypted) files on the department shared drive from backup. In such isolated instances, there was no impact to clinical operations and patient care. However, the story would have been different in the case of widespread infection on the network.
Several healthcare providers in Washington, California and Kentucky were publically impacted in 2016 by what appears to be widespread ransomware infection across many different devices in a short amount of time.
Prevent and Minimize the Impact of Ransomware
There are many things that your healthcare organization should be doing to minimize the impact of successful ransomware attacks. Here are a few tips to get you started:
Effectiveness
Mitigation Type
Activity
High
Minimize Impact
Develop and execute a plan for an end user awareness program
Yes, I know it’s difficult to get approval to send regular hospital-wide security advisories, but smarter end users will surely result in fewer ransomware incidents.
High
Minimize Impact
Review / Validate Server Backup Processes
Some organizations don’t realize their backups are compromised or were configured improperly until it’s too late. You may need them to restore service.
Start with your File Servers that host network shares for critical hospital departments
Ensure you have backups that are not accessible by end users – ideally off-site. Backup administrator roles should be assigned sparingly, used sparingly and regularly audited.
Test your backups regularly to validate they can be restored properly.
Medium
Minimize Impact
Review network drive permissions to minimize the impact that a single user can haveEnd User Privilege Reviews
Assign a project manager to organize an effort to evaluate permissions that users have on mapped network drives. Implement the principle of least privilege to minimize the impact that any single user can have on the organization’s network shared drives.
This process could turn into a large, complex effort, so start with network drive locations used by critical departments (Emergency, Organ Transplant etc).
Administrator User Privilege Reviews
Audit privileged roles used by the Server, Backup & Network Teams to validate appropriate access.
Ensure administrators are assigned normal restricted accounts, separate from their highly privileged accounts.
Require administrators to only use their highly privileged accounts when they need them.
Remove automatic network drive mappings from administrative accounts, where possible.
Restrict administrative accounts from receiving email.
High
Prevention
Disable macro scripts from MS Office files using AD Group Policy
Office macros are usually not required for the majority of PCs used in healthcare environments. Enable macros for exceptions or certain departments only.
High
Prevention
Review your monthly patch management processes
Many hospitals struggle to patch their systems within 30 days of Microsoft’s “Patch Tuesday” monthly patch release.
Review your patching processes and look for opportunities to remove roadblocks.
Consider deploying an advanced endpoint product that prevents exploits due to missing patches and malware.
Medium
Prevention
Evaluate your inbound spam / malware protection
Ensure you are configured to block inbound mail as per recommendations from your email server vendor (i.e. block executables in attachments etc)
High
Prevention
Deploy a next-generation firewall to protect the hospital network
Ensure your firewall automatically blocks known threats based on a threat feed that constantly updates.
Ensure your firewall provides sandboxing capabilities so you can stop unknown threats (URLs and executables) before they reach the endpoint. Sandboxing is the best way to detect new variants of ransomware that constantly appearing in the wild.
Configure your firewall/proxy to require user interaction for hospital end users communicating with websites uncategorized by the network proxy or firewall (i.e. click a “proceed” button). Many uncategorized websites are used in targeted phishing campaigns to distribute malware.
High
Prevention
Deploy advanced endpoint protection to protect the endpoint
Traditional antivirus is not effective anymore against advanced malware like ransomware which continuously changes to avoid detection. Your endpoints need advanced protection capable of stopping processes that exhibit malicious behavior, rather than checking for individual known bad files.
Whitelisting can work for some organizations but most hospitals need to permit hundreds of applications across their departments so it is often difficult for IT to manage the list.Behavior-based malware detection tends to be very effective, and also lightweight on the endpoint.
These suggestions range from low-tech to high-tech and vary in cost, but all contribute to create a hospital environment that is highly resistant to ransomware with the least amount of manual management. Decide for yourself which combination of mitigating activities is best for your environment.
If you want to read more about the history of ransomware – take a look at The Rise of Ransomware, a recent paper from our threat intelligence team, Unit 42.
Dr. Philip Cao (aka #DrTekFarmer), EDBA, MSCS, ZTX-I, CCISO, CISM, CMSC, CCSP, CCSK, CASP, GICSP is a Strategist, Advisor, Contributor, Educator and Motivator. He’s also a Cyber | Zero Trust Strategist & Evangelist and Chief Trust Officer. He has 23 years’ experience in IT/Cybersecurity industry in various sectors & positions.
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