P2PE Versus E2EE Revisited

It has been almost four years since I wrote the original post.  I went back and reread the original and realized it needed a rewrite to make the comments accurate and current.  Point-to-point encryption (P2PE) and end-to-end encryption (E2EE) are a key part to merchants minimizing their PCI scope (the other technology is tokenization) to the maximum.  However, I continue to encounter a lot of organizations that are confused about the difference between the PCI SSC’s P2PE certified solutions and E2EE solutions.  This is understandable as even those in the PCI community are confused as well.

E2EE is the generic terminology used by the IT industry to describe any solution that encrypts communications from one endpoint to another endpoint.  Key management of the encryption can be done by any party that has an endpoint such as a merchant or a service provider.  Examples of E2EE include IPSec, SSH and TLS.  In transaction processing, E2EE solutions pre-date P2PE by a number of years as numerous transaction processors and point of interaction (POI) vendors had E2EE solutions before the publication of the P2PE standards.

One of the most common E2EE solutions used by merchants is derived unique key per transaction (DUKPT) also known as “duck putt”.  DUKPT is commonly used in the convenience store and gas station industries to encrypt sensitive authentication data (SAD) from the gas pump to the merchant or processor.  DUKPT originally used the 56-bit data encryption standard (DES) encryption algorithm but was updated to 168-bit 3DES and later to AES.  While DES is no longer considered secure, because DUKPT uses a unique key for every transaction, it means that every transaction has to be individually broken to gain access to the data – a time consuming task given the usual large transaction volumes.  While the cloud could be leveraged to perform this decryption rapidly, it would be too costly an effort for the data retrieved.  As a result, DUKPT using DES is still technically considered a secure method of encryption although it is never recommended for use.  3DES and AES are now the more commonly implemented algorithms with AES being the preferred solution if supported by the POI.

One of the big changes with v2 of the P2PE standard was to simplify the certification process which vendors complained was overly complicated and cumbersome in v1.  As a result, the Council responded by simplifying the certification process by adopting a more modular approach.

The other big change was to allow merchants to be in control of key management.  The key management change was driven by P2PE vendors who were finding that large merchants needed to manage their POI encryption keys because they desired to do their own transaction switching between processors.  As a result, large merchants were implementing E2EE solutions rather than P2PE solutions so they could perform encryption key management.

The Council then came up with the Non-Evaluated Solution Assessment (NESA) program a few years ago.  The idea was that P2PE-QSAs would assess the E2EE solutions and produce a report so that merchants could more readily obtain P2PE scope reduction from their banks.  One of the reasons that NESA never caught on was that the Council never really created and shared a good definition of what a NESA report would contain for proof and the format.  QSAs have never had a clear definition of what, if anything, was required to be reported.  As a result, how was a QSA to rely on a document that had no definition?  But what the Council really missed was the fact that most E2EE solutions are approved by the acquiring bank because they are offering it to their customers.  Since the bank determines whether a merchant gets P2PE scope reduction with E2EE solutions, there really was no need for the NESA program.  Never mind the fact that none of the card brands mandated the NESA process.

One of the biggest issues I encounter over E2EE is that merchants believe that E2EE solutions are not acceptable for reducing PCI scope.  That is because the key difference between P2PE and E2EE is that a P2PE solution gives immediate PCI scope reduction as long as it is properly implemented.  A QSA can reduce PCI scope as long as the P2PE solution is implemented according to the P2PE solution’s Implementation Guide (IG).  The acquiring bank’s approval is not required.  That reduction in scope reduces the amount of testing a QSA is required to perform to those requirements in the SAQ P2PE.

To get P2PE scope reduction with an E2EE solution requires a bit more effort, but it does not have to be extensive.  In my experience, contacting a merchant’s acquiring bank can be all a merchant needs to do.  I remember being on a conference call with a client’s acquiring bank to discuss scope reduction for their E2EE solution.  The bank’s representative inquired as to why the call was needed because the E2EE solution was provided by the bank.  I stated that I needed a formal statement for my work papers indicating that the bank approved of my client’s P2PE scope reduction.  The person laughed, made a comment about how silly PCI can be and then emailed me the P2PE scope reduction approval.

A QSA should still do some investigation work of the E2EE solution to ensure it has been properly implemented regardless of what the bank might say.  Those efforts should include:

• Network packet captures at key points on the customer’s network to ensure that the packet remains encrypted. Those captures should include comparing the payloads to ensure decryption/encryption does not occur along the network path.  This can be done at the customer’s testing lab.
• If the POI is not stand alone and connects to a PC via USB, collect a packet capture of the USB connection using Wireshark’s USB capture solution or a similar solution. This can be done at the customer’s testing lab.
• Use the E2EE solution’s Implementation Guide (IG) to ensure that the E2EE solution was implemented according to the vendor’s instructions. Conduct a visit to a sample of retail locations to ensure that those locations match the configuration and connectivity you observed in the testing lab.
• If the customer is managing the E2EE solution keys, investigate and document the key management to ensure they comply with the key management requirements in 3.5 and 3.6 of the PCI DSS and requirements in Domain 6 of the P2PE Solution Requirements and Testing Procedures v2.
• If the customer is managing the POI key injection process, investigate and document that process to ensure the POI remain secure throughout the process from injection to delivery at the retail location.

These E2EE testing efforts are typically negligible, so any assessment savings over using a P2PE certified solution are limited at best based on my experience.

The huge downside to P2PE for merchants is that once you decide on a given P2PE solution, you are pretty much stuck with it and the processor providing it.  That is because most processors offering P2PE are only offering one P2PE solution.  As a result, if a better deal comes along for processing your transactions, you will likely have to replace your terminals and possibly other equipment to switch to the new processor.  This is why a lot of Chief Financial Officers are a bit put off by P2PE.  For some merchants, that could be a costly proposition and make any switch not worth the effort.  The P2PE switch limitation is a tad bit less with E2EE but even then you will be limited to processors that support your E2EE solution and the conversion will require reinjection of POI keys by the new processor which might not be as seamless or even impossible to perform thus resulting in getting new POI.

If your organization is looking at P2PE versus E2EE, I would not necessarily give the advantage to P2PE.  Just because an E2EE solution is not P2PE certified does not mean it is not secure.  It only means that the vendor did not believe that the P2PE certification was worth the effort.

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Can I Use SSAE 18 SOC 2 Reports? Part 2

In the last post I discussed what the SOC reports are and what, in general, to look for in a SOC 2/3 report.  Now I want to take you through the more detailed analysis of the SOC reporting so that you can understand why it might not give you the result you desire and how to address that fact.

How Do I Analyze The SOC Report?

Based on the testing in the ‘Information Provided by Independent Service Auditor’ section, you are going to need to map that testing into the PCI ROC tests, if they even fit.  I typically use the Prioritized Approach spreadsheet to do this as it provides a way of documenting the requirements covered and a quick dashboard regarding what is covered.

As you reviewed the domains listed under the SOC 3 report, I am sure you thought; “What is not to like?  It looks like most of what I need for PCI is covered.”  But you would be wrong.  You will find after you map the controls from any SOC 2 report that covers all the TSP domains into the Prioritized Approach that the report will likely only cover around 20% to 25% of the PCI DSS requirements.  That is because the level of detail in the SOC tests are just not as detailed as they are in the PCI DSS.  As a result, SOC 2 reporting does not provide the kind of reliance you need to respond to all of the relevant PCI DSS requirements.

For example, while SOC will likely test that password controls are in place, you will be unable to ascertain if the organization enforces seven character or greater password lengths, password complexity, nor if they require passwords to be changed every 90 days or less.  Let alone if the special requirements for vendor password management are enforced.  It is these missing details that create the coverage problems with using the SOC reporting results.

The same can be said for change management.  When tested, the SOC report will likely call out a lot about change management, but not at the level of detail required in the PCI DSS for requirements under 6.4.  You will also find that coverage in requirements 1 and 2 regarding network and server configurations will be lacking in specificity to meet the PCI DSS testing.

Now as a QSA, you have a decision to make.  Can you accept only 20% to 25% of coverage of PCI DSS requirements as being PCI compliant?  I know I cannot.  I need much more to work with before I can get comfortable that a SOC report provides the necessary coverage for PCI compliance.

Now What?

You and your client have expended all this effort and are no closer to the result desired than when this process started.

So, what to do next?

Work with your service providers that provide you SOC reports to include testing that adds the PCI DSS details that are missing.  There will likely be a bit of push back from these service providers because adding testing to their SOC reports will cause the cost of their SOC reports to increase, sometimes significantly.  So be prepared for it.

What you need to do is to have their auditors add the necessary testing details to the description of controls and then have them test that they are in place.  Examples include:

• Password length, complexity, change frequency and the procedures followed to perform a password reset.
• Details surrounding privileged and general user management including provisioning, management approvals, users are implemented with least privilege and users are disabled or removed when terminated.
• Changes tested for segregation of duties between developers and operations, segregation of test, QA and production environments, production data not used for testing, developers do not have unrestricted access to production, test data and accounts removed before applications are promoted to production, changes document impact, they are appropriately authorized, they have been tested, they have been vulnerability assessed and they document backout procedures.
• If encryption is used to protect data, document the algorithms used, are key custodian agreements in place, are split key processes in place if performing manual key management, indicate if a hardware security module (HSM) is used and are keys changed when their crypto-periods expire or they are believed to be compromised.
• Document the configuration standards that are followed by device classes such as firewalls, switches, servers and test that they have been implemented.
• Document that anti-virus is implemented on systems commonly affected by viruses and malware, what the anti-virus solution is that is implemented, the anti-virus solution cannot be disabled and that the anti-virus solution is actively running on all systems it is installed.
• Document that vulnerability scanning is performed, how often scanning is performed and that vulnerabilities are remediated.
• Document that penetration testing is performed, how often penetration testing is performed and that findings are remediated.
• Document that log data is collected from all devices, it is reviewed at least daily and that it contains a date/time stamp, device name, type of log entry and other relevant information.

There are a lot of other areas that could be added to the SOC report, but these are, in my opinion, the bare minimum that need to be added to make the SOC report more relevant for PCI.  I am trying to balance the amount of additional information needed versus the cost of providing it in the SOC report.

By adding all of this will it cover all of the gaps between SOC and PCI?  No.  But it should give your QSA significantly more comfort that the controls in place to meet PCI than what is currently being provided by CPAs.

Can I Use SSAE 18 SOC 2 Reports? Part 1

This is a common question that QSAs encounter from clients.  The client has an SSAE 18 Controls at a Service Organization (SOC) report from one of their service providers and they want to know if they can use it to satisfy any or all of the requirements in 12.8, 12.9 and 12.11 related to vendor management?

The biggest caveat in this discussion is that the PCI SSC does not sanction the use of any report other than a PCI Attestation Of Compliance (AOC) and/or a PCI Report On Compliance (ROC) in addition to any other PCI reports.  The Council has repeatedly stated that if a QSA chooses to rely on an SSAE 18 SOC 2 report (or any other compliance report for that matter), the QSAC and their client accepts the risk if the SSAE 18 SOC 2 does not cover what the QSA claims it covers and therefore relies upon it for fulfilling PCI ROC requirements.  As a result, most QSAs will not accept an SSAE 18 SOC 2 report (or any other non-PCI compliance reports) for any reason.

For those of us “recovering” certified public accountant (CPA) types that have conducted SSAE18 audits, we know how to read and interpret these reports.  As a result, when we are asked about SSAE 18 SOC 2 reports being relevant, our answer is that, “It depends on what the SOC 2 covers and how it was tested.”

Before we get too deep into this discussion though, we need to define the terminology surrounding this topic.  The first thing is that SSAE 18 replaced SSAE 16 as of 2017 even though nothing else appears to have changed.  The next key thing anyone needs to know about SSAE 18 is that there are three reports that can come from this reporting series: SOC 1, SOC 2 and SOC 3.

The first, SOC 1, is for financial auditors only.  It used to be called a SAS 70 years ago.  It is a report focused on financial controls that an external auditor needs to ensure that the financial numbers coming from the third party can be relied upon in their annual audit of their client.  Yes, these SOC 1 reports can cover security controls, but that is only in regard to financial systems, not necessarily the third party’s entire environment.  In addition, the control coverage is typically not as deep as required for PCI compliance.  The bottom line is that any reliance on a SOC 1 report outside of financial systems should never be assumed.

I am going to cover the SOC 3 report next because it covers all of the security domains.  The SOC 3 report (also sometimes referred to as the ‘SysTrust’ report) covers the following domains:

• Organization and Management – The criteria relevant to how the organization is structured and the processes the organization has implemented to manage and support people within its operating units.
• Communications – The criteria relevant to how the organization communicates its policies, processes, procedures, commitments, and requirements to authorized users and other parties of the system and the obligations of those parties and users to the effective operation of the system.
• Risk Management and Design and Implementation of Controls – The criteria relevant to how the entity (i) identifies potential risks that would affect the entity’s ability to achieve its objectives, (ii) analyzes those risks, (iii) develops responses to those risks including the design and implementation of controls and other risk mitigating actions, and (iv) conducts ongoing monitoring of risks and the risk management process.
• Monitoring of Controls – The criteria relevant to how the entity monitors the system, including the suitability, and design and operating effectiveness of the controls, and takes action to address deficiencies identified.
• Logical and Physical Access Controls – The criteria relevant to how the organization restricts logical and physical access to the system, provides and removes that access, and prevents unauthorized access to meet the criteria for the principle(s) addressed in the engagement.
• System Operations – The criteria relevant to how the organization manages the execution of system procedures and detects and mitigates processing deviations, including logical and physical security deviations, to meet the objective(s) of the principle(s) addressed in the engagement.
• Change Management – The criteria relevant to how the organization identifies the need for changes to the system, makes the changes following a controlled change management process, and prevents unauthorized changes from being made to meet the criteria for the principle(s) addressed in the engagement.

There are also some additional considerations that are related to Confidentiality specified in the Trust Services Principals and Criteria (TSP), but those are not required to be covered in the SOC 3 report.

Finally, there is the SOC 2 report.  The SOC 2 report uses the same TSP as the SOC 3 but with a twist.  The third party can select any or all of the seven domains to be assessed.  Think of it as a “cafeteria style” assessment.  With the SOC 2, the AICPA does not require that all domains be covered (as with the SOC 3), the assessed entity can select only those domains they wish audited.  As a result, a third party could select only the ‘Organization and Management’ domain to be assessed and nothing else in their SOC 2 report.  Therefore, just because you have a SOC 2 does not mean it covers the domains necessary for your PCI assessment.  Like the SOC 3, in addition to the seven domains, the SOC 2 can also cover none, any or all of the additional considerations documented in the TSP.

Within each of these SOC reports there is a Type I and a Type II report.  A Type I report is basically worthless from a reliance perspective because no testing of the controls is ever performed.  With a Type I report, the auditor is signing off on the fact that the third party has controls defined and formally documented.  But without testing, there really is no point to this report.  Yet every now and then, I encounter a Type I report that an organization has relied upon for years.

The only report worth anything is a Type II report which tests the control environment to ensure that the controls are functioning as designed.  So, when you get that SOC 2 report, you need to make sure you have a Type II report where testing has been performed by the auditor.  Even then though, the report might not be as useful as you might think.

I Have A SOC 2 Type II Report From A Service Provider

While you want to read the whole report in detail, when I am pressed for time and cannot read it in its entirety, here is where I focus so that I can get a quick view of what I have.  Some CPA firms provide a one-page Executive Summary that gives the reader a quick overview of the report, provides the timeframe the report covers, opinion, exceptions and other useful information.  But that is not required by the AICPA so you cannot always rely on such an overview being in every report you receive.  When they are available, they can help you focus your quick review efforts even better.

The first thing to do is to read the auditor’s opinion which should be the first section of the report.  It is in the form of a letter on the auditor’s letterhead and signed by the auditing firm.  The opinion the auditor provides will be either:

• Unqualified – no material control weaknesses or failures were identified.
• Qualified – some material control weaknesses or failures were identified.
• Adverse – significant control weaknesses or failures were identified.

An unqualified opinion is what all organizations desire and what most reports document.  But do not be fooled by an unqualified opinion.  There still could have been control weaknesses or failures identified but they did not rise to the level of being considered “material”.  I have seen some unqualified reports with control weaknesses that I would have considered material as their auditor, so you might still want to contact the organization to get clarification on any weaknesses identified.

A report with a qualified opinion is not the end of the world, but that will all depend upon what control weaknesses or failures created the qualification.  Someone misusing their access can be minor compared to not performing backups of servers for months.  As a result, you need to read each control weakness to determine the criticality of the control failure as well as review management’s responses to how they addressed or will address the failure.  Again, you may find yourself contacting the organization to clarify weaknesses documented.

In my experience, reports with an adverse opinion never get issued to the public.  Management sees all of the control failures and weaknesses and then embarks on the long arduous task of cleaning up their control environment.

The next section to look at is the one labeled ‘Information Provided by Independent Service Auditor’ or similar.  This is the section that will contain the testing results and will define which of the domains were covered as well as the timeframe the report covers.  Most organizations issue SOC reports annually, so you always want to make sure that you have the most current report.  If the coverage end date is getting within three months of a year old or more, you should contact the third party and ask them when the next report will be issued.  They should inform you that the new report is in progress and give you an estimated date the report will be issued.  If they do not give you a succinct answer, I would be concerned.

You need to go through this section looking at a couple of things.  The first is to determine which of the domains were covered.  While documenting those domains, you also need to review the testing that was performed and at what level of detail those tests were conducted.  For example, it is not unusual to see tests for change control cover five random changes but not test those changes for having appropriate documentation, backout instructions and testing, only that the changes were approved.  At some point you will need to read this section carefully to determine what, if anything, will cover the testing required by the PCI DSS.  But a quick perusal will usually give you an idea of what you are likely going to get out of the SOC 2 for PCI compliance, if you are going to get anything at all.

This leads to the next section of the report you should read.  The last section of all SOC reports is usually titled ‘Supplemental Information Provided By [Organization Name]’.  This section contains information that was provided by the entity being audited but is not covered by the auditor’s opinion.  There can be all sorts of information presented here but the important point to remember is that the auditor did not test or assess the accuracy of that information.  So, you need to take any information provided in this section with a bit of skepticism.

It is in the Supplemental Information section that you want to look for a sub-section titled ‘Management’s Response to Control Exceptions’ or similar.  Even when an organization has an unqualified opinion, there can still be items listed in this section.  If there are items listed, you want to carefully read what those items were and how management addressed or corrected the condition.  If you find any control issues and responses that concern you, you should contact the entity and get those discussed so that you are comfortable with the situation.  If you cannot get comfortable with the situation, then you may want to consider additional controls at your end to compensate for the control weakness with the third party.

In the next postpost I will take you through a more thorough review of the SOC report.