Health-ISAC Threat Bulletin

Date: May 4, 2020

TLP: White

Event: NSA Releases Telehealth Guidelines During COVID-19


The National Security Agency (NSA) recently shared cybersecurity guidance with high-level security assessments to help organizations select and safely use collaboration services to support the increase in remote work during the COVID-19 pandemic.

There are many consumer and enterprise-grade communication solutions available and the cybersecurity protections offered by each can differ considerably. The guidance document from the NSA outlines nine important considerations when selecting an on-line collaboration service. By assessing each service against the nine criteria, remote workers will be able to choose the most appropriate solution to meet their needs.



1. Does the service implement end-to-end encryption?

End-to-end (E2E) encryption means that content (text, voice, video, data, etc.) is encrypted all the way from sender to recipient(s) without being intelligible to servers or other services along the way. Some apps further support encryption while data is at rest, both on endpoints (e.g. your mobile device or workstation) and while residing on remote storage (e.g. servers, cloud storage). Only the originator of the message and the intended recipients should be able to see the unencrypted content. Strong end-to-end encryption is dependent on keys being distributed carefully. Some services such as large-scale group video chat are not designed with end-to-end encryption for performance reasons.


2. Are strong, well-known, testable encryption standards used?

Even in the absence of end-to-end encryption, NSA recommends the use of strong encryption standards, preferably NIST-approved algorithms and current IETF secure protocol standards. Many collaboration services protect data-in-transit between clients and servers via the Transport Layer Security (TLS) version 1.2 (or later) secure protocol, which is commonly used for sensitive but unclassified information. Use of published protocol standards, such as TLS and DTLS-SRTP, is preferred. If the product vendor has created its own encryption scheme or protocol, it should undergo an independent evaluation by an accredited lab. This includes not just cryptographic protocols, but also key generation.


3. Is multi-factor authentication (MFA) used to validate users’ identities?

Without MFA, weak or stolen passwords can be used to access legitimate users’ accounts and possibly impersonate them during use of the collaboration service. Multi-factor authentication requires that a second form of identification (code, token, out-of-band challenge, etc.) be provided to allow access to an existing account.


4. Can users see and control who connects to collaboration sessions?

The collaboration service should allow organizers to limit access to collaboration sessions to only those who are invited. This can be implemented through such features as session login passwords or waiting rooms, but preferably would support reasonably strong authentication. Users should also be able to see when participants join through unencrypted/unauthenticated means such as telephone calls.


5. Does the service privacy policy allow the vendor to share data with third parties or affiliates?

While collaboration services must often collect certain basic information needed to operate, they should protect sensitive data such as contact details and content. Collaboration information and conversations should not be shared with third parties. This could include metadata associated with user identities, device information, collaboration session history, or various other information that may put your organization at risk. Information sharing should be spelled out clearly in the privacy policy.


6. Do users have the ability to securely delete data from the service and its repositories as needed?

While no services are likely to support full secure overwrite/deletion capabilities, users should be given the opportunity to delete content (e.g. shared files, chat sessions, saved video sessions) and permanently remove accounts that are no longer used.


7. Has the collaboration service’s source code been shared publicly (e.g. open source)?

Open source development can provide accountability that code is written to secure programming best practices and isn’t likely to introduce vulnerabilities or weaknesses that could put users and data at risk.


8. Has the service and/or app been reviewed or certified for use by a security-focused nationally recognized or government body?

NSA recommends that cloud services (which collaboration apps rely on) be evaluated under the Office of Management and Budget (OMB) FEDRAMP program. NSA also recommends that collaboration apps be evaluated by independent testing labs under the National Information Assurance Partnership (NIAP) against the Application Software Protection Profile (PP) [1]. NSA has worked with the DHS S&T Mobile Security R&D Program to develop excellent semi-automatable testing criteria for app vetting based on the application PP [2]. These criteria include tests of how apps interact with platform resources, how they defend themselves from exploitation, the crypto libraries they use, what permissions they request, and many others.


9. Is the service developed and/or hosted under the jurisdiction of a government with laws that could jeopardize USG official use?

Since it is well documented that some countries require that communications be provided to law enforcement and intelligence services, it may not be wise for certain USG missions to be performed on services hosted or developed under certain foreign legal jurisdictions. Users should be aware that the country of origin where products were developed is not always public knowledge. This criterion was not assessed in the table on page 5.



· The NSA strongly recommends conducting high-level security assessments to determine how the security capabilities of each platform performs against certain security criteria. These assessments are useful for identifying risks associated with the features of each tool. The guidance document also provides information on using the collaboration services securely.

· The NSA recommends the guidance should be reviewed by all employees who are now working from home to allow them to make an informed decision about the best communication and collaboration tools to use to meet their specific needs, and for workers to take the steps outlined in the guidance document to mitigate risks of cyberattacks.




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