Archive for March 23rd, 2020

23
Mar
20

Work From Home PCI Considerations

The PCI Guru got a question regarding PCI compliance for service providers in today’s emergency work from home (WFH) environment from a blog reader and it got The PCI Dream Team thinking about how does that work?  So, thanks to David Mundhenk of Herjavec Group, Art “Coop” Cooper of NuArx, Ben Rothke of Tapad and Jeff Hall of Online Business Systems for contributing to this list.

Ben & David wrote a piece on the topic last week, and the Dream Team has a webinar on Dealing with PCI DSS Compliance During the COVID-19 Crisis on March 25.

Thanks to the Coronavirus crisis, organizations are now scrambling to get their employees working from home.  This is presenting a whole new series of challenges to their compliance, technology and information security teams as these employees are now operating in a potentially less secure and definitely less private environment.

Home networks are going to be less controlled and secure.  Making matters worse is that most home networks today are Wi-Fi based, not wired, so data is flowing over untrusted networks because everyone in the house knows the Wi-Fi password (assuming there is one and it is not the default).

Bring Your Own Device (BYOD)

The biggest issue we are encountering is those organizations that need to rely on workstations owned by employees because they do not have company-owned and configured equipment to provide.  I have seen many a Tweet and LinkedIn post discussing the shortages of equipment for work from home and what options do they have.  The problem stems from most business continuity plans focusing on events that affect a business location or a community, not the entire country.  As a result, the idea of a pandemic forcing people to work from home was not thought of as a realistic threat.

As a result, bring your own device (BYOD) is the only answer in the near term to getting people working from home.  In discussions not only amongst the Dream Team but with other QSAs, there just do not seem to be any good answers for using BYOD and maintaining PCI compliance.  None of us can come up with ways to maintain compliance with BYOD because there are just too many factors involved from anti-virus (many varieties), limited or non-existent central monitoring and management, vulnerability scanning, penetration testing, patching, differing hardware, differing operating systems and a host of other issues that make it impossible to verify compliance let alone maintain compliance.

One potential option to reduce risk and gain better control with BYOD is using virtual desktop infrastructure (VDI) solutions such as Citrix Workspace, VMware Horizon or Windows Remote Desktop Services.  If you have that infrastructure in place, then we would recommend expanding it for WFH remote access.  If you do not have that infrastructure, you may be able to use Amazon Web Services (AWS), Microsoft Azure, Google Cloud or similar cloud environments to stand it up quickly.  That would allow you to reduce the risk of the BYOD being used but there still would be the risk of memory scraping and keyboard logging on the BYOD that must be managed.

That is not to say that you should not use BYOD as you need to keep your business running.  What it does mean is that you need to have a serious talk to your acquirer to determine how to handle this situation, what the risks are to your solution and then communicate the results of that discussion formally to your QSA.  You may even want to have your QSA on those calls with your acquirer to assist.  In these desperate times, I doubt that any bank is going to say you cannot stay in business as long as you can provide some controls and do your best to manage the risk.

We view BYOD though as a short term solution and that a longer-term solution needs to be developed as current estimates seem to indicate that the crisis will likely extend past the original estimate of four weeks.  That longer-term solution would involve acquiring the necessary hardware and software to implement a managed, secured and controlled environment that can be tested to ensure PCI compliance.

Company Provided Hardware and Software

For those companies that do have the equipment to send home with their employees, this is not a complete list, but a set of bullet points of ideas for how to address PCI compliance in our “new normal”.

  • The easiest topic is remote access. The PCI DSS explicitly calls out that a secure VPN (i.e., encrypted) with multi-factor authentication (MFA) for users to obtain access to the service provider network (8.3.2.a).  But where things can go sideways is complying with 8.3.1.a which requires MFA for non-console access to systems/devices in the cardholder data environment (CDE).  It goes awry because people think that the first MFA covers the MFA into the CDE and it does not.  The reason is that 8.3.1.a was designed to stop the phishing of Administrators to gain access to the cardholder data environment (CDE).  To stop that, you need additional MFA to access the CDE.  That does not mean a separate MFA solution (which would be ideal), but it does mean enforcing a delay in the single MFA so that the same MFA code cannot be used to access the internal network and then also the CDE.  A lot of organizations implement the delay in their remote logon script by invoking a timer delay that expires after the longest time a code can be active (usually 30 seconds).
  • A secure VPN is necessary to remove the home network from scope. Ideally, the VPN should be required to always be in use so that the workstation cannot get to the internet other than over the VPN.  For those that do allow the home network and internet to be accessible, you will need to ensure that the firewall on the workstation appropriately protects the workstation as well as implementing a host intrusion detection solution (HIDS).
  • VDI is also a solution because it allows for the use of thin-client and devices such as Chromebooks to be used to connect. Most VDI solutions also embed a secure remote connection via HTTPS or similar secure connectivity solutions.  If not then you will need to use a secure VPN as documented above.  However, even a thin client runs the risk of memory scraping and keyboard logging so you need to manage those risks.
  • Review all automated workflows to make sure that they are producing the necessary audit trails that will provide evidence for you PCI assessment of what is happening. Where this becomes problematic is when the workflows are developed only for PCI compliance and with the changes for remote operations, those workflows are not picking up new users, devices and other changes that were made to allow for remote work.
  • People that typically work together but now are remote will start using Microsoft Teams, Slack, Skype and other collaboration platforms to communicate and that may include sharing cardholder data (CHD) or sensitive authentication data (SAD) at times. You will need to train and quickly remediate situations if CHD/SAD enters these applications as well as periodically reminding these people that the use of these communication systems for transmitting SAD/CHD is not allowed.  If possible, enable data loss prevention (DLP) or similar capabilities to identify and then redact SAD/CHD in any of these communications.
  • If you are pushing out call center operations, remember that softphones will bring the workstation they connect into scope for PCI compliance because the workstation is now directly connected to the CDE which is, of course, the VoIP telephone system. That means an increase in scope and that those workstations need to be hardened, managed, logged and controlled for PCI compliance.  Call center operations may also require additional network segmentation to be put in place to ensure the size of your CDE does not exponentially grow.
  • While not entirely PCI related but needs to be noted are some other remote call center operation issues to consider that could make compliance with contractual obligations regarding privacy and confidentiality of data discussed or processed by the operator. You may need to supply operators with shredders, printers, additional monitors and other equipment to ensure privacy and productivity.  You may also have to instruct people to locate their work area to a bedroom or other room where a door can isolate the operator while they work so that family members do not come into contact with information or documents they should not view.
  • Ensure that you have ways to document changes happening, their review and approval. A lot of organizations have paper forms, Excel spreadsheets, email forms, etc. they use that sometimes can get lost in people’s inboxes, archives and folders or just lost, period.  You need to make sure that the change management system will work in the remote mode and that change evidence, reviews and approvals are maintained.
  • Logging should not be an issue unless your organization was not logging the VPN or other devices because they were not in scope for PCI compliance but now are in scope. So, you need to review your new workflows to ensure all devices and systems are logging to your SIEM or logging solution so that you comply with PCI requirement 10.
  • Encryption key management could become an issue particularly if your process does not support remote management. This can happen with some hardware security modules (HSM) and systems that require that the key custodians physically input their seed values into the device’s console.  So, going on-site may be required for encryption key changes and that may require formal approval from local authorities to occur.

These are the top of mind ideas that we were able to come up with for this discussion.  However, every environment is different so not everything discussed may be possible for your organization to use and maintain compliance.  We would recommend you work with a QSA to make sure that what you are attempting to do is not creating risks you are unwilling to accept or if you cannot manage appropriately.

We wish all of you the best of luck during this crisis.  We will get through this, but it will likely take some ingenuity in how that happens.

Also, be aware that the Council and the Card Brands are working on this topic as well and I expect more from them in the coming weeks.

Stay safe and healthy.

 

Other WFH resources:

CISA Coronavirus Guidance – https://www.cisa.gov/coronavirus

NIST Teleworking Guidance – https://csrc.nist.gov/publications/detail/sp/800-46/rev-2/final

SANS Work From Home Webcast – https://www.sans.org/webcasts/archive/2020




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