In my very first job we were told, repeatedly told, to document everything and keep our personal journals up to date. Not just with what we did but the reasoning behind those decisions. This was so that if anything happened to use kn knowledge about the work, the project, what had been tried and thought about was lost, if, perhaps, we were 'hit by a bus on the way to work'.
At that point whoever was saying this looked toward a certain office or certain place in the parking lot. One of the Project managers drove a VW bus and was most definitely not a good driver!
So the phrase 'document everything in case you're hit by a bus' entered into the work culture, even after that individual had left.
And for the rest of us it entered into our person culture and practices.
Oh, and the WHY is very important. How often have you looked at something that seems strange and worried about changing it in case there was some special reason for it being like that which you did no know of?
Unless things get documented .... Heck a well meaning 'kid' might 'clean it out' ignorant of the special reason it was like that!
So here we have what appear to be undocumented controls.
Perhaps they are just controls that were added and someone forgot to mention; perhaps the paperwork for these 'exceptions' is filed somewhere else or is referred to by the easily overlooked footnote or mentioned in the missing appendix.
It has been pointed out to me that having to document everything, including the reasons for taking one decision rather than another, "slows down work". Well that's been said of security, too, hasn't it? I've had this requirement referred to in various unsavoury terms and had those terms associated with me personally for insisting on them. I've had people 'caught out', doing one thing and saying another.
But I've also had the documentation saving mistakes and rework.
These days with electronic tools, smartphones, tablets, networking, and things like wikis as shared searchable resources, its a lot easier.
Sadly I still find places where key documents such as the Policy Manuals and more are really still "3-ring binder" state of the art, PDF files in some obscure location that don't have any mechanism for commenting or feedback or ways they can be updated.
Up to date and accurate documentation is always a good practice!
 And what surpises me is that when I've implemented those I get a 'deer in the headlight' reaction from staff an managers much younger than myself. Don't believe what you read about 'millennials' being better able to deal with e-tools than us Greybeards.
How do you know WHAT assets are to be included in the ISO-27K Asset Inventory?
This question and variants of the "What are assets [for ISO27K]?" comes up often and has seen much discussion on the various InfoSec forums I subscribe to.
Perhaps some ITIL influence is need. Or perhaps not since that might be too reductionist.
The important thing to note here is that the POV of the accountants/book-keepers is not the same as the ISO27K one. To them, an asset is something that was purchased and either depreciates in value, according to the rules of the tax authority you operate under, or appreciates in value (perhaps) according to the market, such as land and buildings.
Here in Canada, computer hardware and software depreciates PDQ under this scheme, so that the essential software on which you company depends is deemed worthless by the accountants. Their view is that depreciable assets should be replaced when they reach the end of their accounting-life. Your departmental budget may say different.
Many of the ISO27K Assets are things the accountants don't see: data, processes, relationships, know-how, documentation.
From the left hand doesn't know what the right hands is doing department:
Ngair Teow Hin, CEO of SecureAge, noted that smaller companies
tend to be "hard-pressed" to invest or focus on IT-related resources
such as security tools due to the lack of capital. This financial
situation is further worsened by the tightening global and local
economic climates, which has forced SMBs to focus on surviving
above everything else, he added.
Well, lets leave the vested interests of security sales aside for a moment.
I read recently an article about the "IT Doesn't matter" thread that basically said part of that case was that staying at the bleeding edge of IT did not give enough of a competitive advantage. Considering that most small (and many large) companies don't fully utilise their resources, don't fully understand the capabilities of the technology they have, don't follow good practices (never mind good security), this is all a moot point.
he documentation required and/or needed by ISO-2700x is a perenial source of dispute in the various forums I subscribe to.
Of course management has to define matters such as scope and applicability and the policies, but how much of the detail of getting there needs to be recorded? How much of the justification for the decisions?
Yes, you could have reviews and summaries of all meetings and email exchanges ..
But that is not and has nothing to do with the standard or its requirements.
The standard does NOT require a management review meeting.