Wednesday, August 06, 2008

Even More Logging Questions - Answered

I did this fun webcast on logging for accountability (here) and people asked a lot of good questions. Here are some of the answers for them and all my blog readers.


Q1: How do you handle variety of log sources? There are so many, almost beyond my capability.

A1: Sorry to ponder the meaning of "is" here, but what is meant by "handle"? It is really not that hard to collect logs from a large number of diverse sources (as long as the logs can be delivered via syslog or exist as files and can be collected). Now, there will certainly be challenges  when the volume of logs gets large, but if by "handle" you mean "collect + store", it is really not that hard, given the right tools. Now, if "handle" means "make sense of what all those logs are trying to tell you," it is a different story altogether.


Q2: You talked about the importance of logging; however for an intermediate or novice admin what are the starting steps .. what are the minimal logs they should start at once?

A2: Answered in "Log Management - Day 1" If you want a simple list of things to "enable today,"  I cannot really answer it since I know neither your needs, nor your environment. In other words, this is the "what is the meaning of life question?" :-)


Q3: What regulations, rules or guidance exist regarding sharing or visibility of logs to users?

A3: PCI DSS says in Requirement 10.5:  "Secure audit trails so they cannot be altered.
10.5.1 Limit viewing of audit trails to those with a job-related need
10.5.2 Protect audit trail files from unauthorized modifications
10.5.3 Promptly back-up audit trail files to a centralized log server or media that is difficult to

NIST guidance for FISMA also says something similar (for example, look in NIST 800-92 doc). Overall, log protection and security are mentioned in many other regulations as well.


Q4: Privileged groups membership monitoring in AD one of the most important from my point of view. However I did not find effective way to monitor/report on changes in those groups. Any recommendations?

A4: This is indeed a tricky one which might take more space to answer than I have here; it might also take you 'beyond logs.' One good source of information is Randy Smith's site and, specifically, his webinar on 'Active Directory "Logging Gap"' (here somewhere) - which covers how to audit things of that sort when then native logging is not sufficient.


Q5: How I can learn what exactly I need to log?

A5: OMG, this is a $1,000,000 question :-) Let me answer "how can I learn" part and not the "what exactly I need to log part,"  (also see discussion on "MUST-DO Logging for PCI?") as it is actually answerable. To learn what you need to log, first ask "Why?" (and then see this) - basically establish what you want to accomplish with logs, catalogue your systems, figure how to tweak the logging knobs - and then do it!


Q6: How granular should logging be? What is your recommendation for enterprise servers like domain servers and Windows servers?

A6: Again, too long to answer here in details (it will become a subject of a longer blog post later), but some pointers follow: here for Windows (MS site also have a few recommendations on audit policies)


Q7: What is "more control" and what is "less control" that you mention in the webcast? Can you give an example?

A7: OK, I did say that "sometimes when you implement more controls, you actually have less control." What do I mean? If you buy a firewall (a network security control) and then - over time, of course - configure it with 7800 rules (!) that are supposed to give you control over who can and cannot access your network, you will not gain control over your environment. You will actually be less in control of who is touching your network, compared to, say, having only 20 rules.


Q8: What about mandated NIST controls for government systems? Auditing is a specific control for Moderate and High risk systems. What list of events do you recommend for auditing?

A8: This is too long to answer here, but NIST 800-92 Guide is a really good source of such info ("Guide to Computer Security Log Management [PDF]") Also, see my presentation on NIST 800-92 Guide in the Real World.


Q9: The issue that many organizations get stuck on, is the monitoring process, and defining what exceptions to monitor for? Is there guidance / framework for this? How much of it is system specific and how much is applicable generally to all systems?

A9: I outlined some general ideas back in 2004 via this presentation (note to self - update that to be more 2008-relevant); it is mostly general, but also has pointers to specific system. Keep in mind that it is focused on security, not operational monitoring (which is often no less important - in fact, often MORE important)


Enjoy! Sorry for being brief with some of the answers - I am woefully late with this even as they are...

Other questions that I answered in the past:

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Dr Anton Chuvakin