PCI SSC: Effective Daily Log Monitoring

PCI SSC: ‘Effective Daily Log Monitoring Supplement’ – They Missed Again

The SSC released their Information Supplement ‘Effective Daily Log Monitoring‘ in MAY, and I’m only just hearing about it now! Either I’m completely out of the loop (not being a QSA) or the SSC did a very poor job PR-ing it.

I think I understand which it is now that I’ve read it.

Anyway, despite the blatant oxymoron in the document’s title, and my own predisposition toward negative bias where the SSC is concerned, I was still hoping to be pleasantly surprised.

I wasn’t, but nor was I as horrified as I have been while reading output from other SIGs.

It’s actually a really good beginner’s guide to logging, but it’s completely unsupported by the DSS in its current form. And it’s not just me looking for faults, they have not put logging into a proper, or even accurate, context to the DSS requirements as written. With their knowledge of best practice, they basically made the rookie mistake of assuming requirements mean more than they do.

To be clear; If it’s not specifically spelled out in the standard, it is not mandatory. Period / full stop. Even if it’s the right thing to do.

For example: There is no requirement for any automated alerting. Not from firewalls, not from A/V, not from IDS, not from FIM, and not from ‘system components’ like servers and applications. So the statement; “The PCI DSS recognizes the importance of proactive monitoring of security logs in the detection of attacks on information assets and the protection of those assets from compromise.” is inaccurate. The SSC might recognise the importance of pro-active monitoring, the SIG’s participants clearly do, but the DSS only recognises the need for what amounts to forensic evidence. Nothing more.

The DSS uses the word ‘alert’ in only 6 relevant Requirements:

  • 6.6  For public-facing web applications, ensure that either one of the following methods is in place as follows:

• Examine the system configuration settings and interview responsible personnel to verify that an automated technical solution that detects and prevents web-based attacks (for example, a web-application firewall) is in place as follows:

– Is configured to either block web-based attacks, or generate an alert that is immediately investigated.” – [Alerts are non-mandatory, and can be manually generated.]

  • 10.5.5  Use file-integrity monitoring or change-detection software on logs to ensure that existing log data cannot be changed without generating alerts (although new data being added should not cause an alert).” – [No time-period defined, so you have to assume weekly like 11.5, or at most daily like 10.6. Alerts can be manualy generated.]
    o
  • 10.6 Review logs and security events for all system components to identify anomalies or suspicious activity.

Note: Log harvesting, parsing, and alerting tools may be used to meet this Requirement.” – [Non-mandatory]

  • 11.1.d  If automated monitoring is utilized (for example, wireless IDS/IPS, NAC, etc.), verify the configuration will generate alerts to notify personnel.” – [Non-mandatory, and/or no time-period defined.]
    o
  • 11.4  Use intrusion-detection systems and/or intrusion-prevention techniques to detect and/or prevent intrusions into the network. Monitor all traffic at the perimeter of the cardholder data environment as well as at critical points in the cardholder data environment, and alert personnel to suspected compromises.” – [Alert how? Automatically or during a daily review?]
    o
  • 11.5  Deploy a change-detection mechanism (for example, file-integrity monitoring tools) to alert personnel to unauthorized modification (including changes, additions and deletions) of critical system files, configuration files, or content files; and configure the software to perform critical file comparisons at least weekly.” – [Weekly notification, so clearly does not require automation.]

So if there’s no requirement for automatically generated alerts, and daily is the maximum defined review timeframe, how can they possibly insist on 24/7 availability related to Incident Response (DSS Req. 12.10.3)? Who is going to choose 2AM for their daily review?

Even the SIG makes the statement; “Without automated alerting mechanisms, it is almost impossible to identify and alert about such events in near real-time.“. In other words, in time to actually do something about it before it gets out of hand.

But I thought this was about effective DAILY log monitoring?

So All In All…

The thing that still confuses me most, is that the DSS is full of mandatory technologies, but a manual and daily review of logs is still OK?! Not one technology in the DSS is required to be utilised properly, and some have significantly less benefit than a Security Incident & Event Management (SIEM) or an equivalent managed service:

  • why require firewalls and routers then don’t mandate review of the traffic logs?
  • why require an asset database, but not an asset management system on which every other security processes can rely?
  • anti-malware is based on signatures so is all but useless
  • intrusion detection is pointless unless the entire infrastructure is baselined to a known-good
  • …and so on.

So of ALL requirements, how can centralised logging and automated alerts not be mandatory?

This post in already too long, and I’ve barely begun to scratch to surface of why logging and monitoring is so important.

There’s no escaping that the document name; ‘Effective Daily Log Monitoring‘ is misleading, it should be called the ‘We Cannot Tell You to Buy a SIEM, But Good Luck Getting Compliant Without One‘. Basically the SSC has all but admitted that the logging and monitoring requirements are completely inadequate, but can think of no way to change them in the DSS. Not without pissing off a lot of people anyway.

Finally, it IS  a good document, worth a read, and kudos to the authors. Unfortunately it’s guidance is meaningless to those without the means to perform anything other than manual daily reviews.

Bonus Material

If you’re interested, I have provided some additional thoughts in my own Logging Supplement document. There are 3 sections:

  1. Breakdown of Existing DSS Logging & Alerting (Non-Server) – There are 5 DSS requirements outside of the established logging and alerting requirements, and are ambiguous at best. They are also not covered appropriately in the SSC’s Supplement.
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  2. Missing from the DSS – The SSC’s Supplement did not cover daily review appropriately, nor did then then go far enough to cover appropriate automation. This section covers a few of the major benefits of logging and monitoring properly.
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  3. Automating the Daily Review – There are only three processes required to automate the daily review, but it cannot be done without centralised logging and scripting skills, a managed service, or a SIEM.

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