Show last modification time of an entry's password

[OLLI-S]

Summary

For some security features you need to determine the modification date of the password, so you should show this date also in the GUI so users can use this information.

Details

For some security features like Check for breaches based on site/service ( #1083 (comment) ) you need to determine the modification date of the password.
This can be the creation date of the entry (if the password was never changed) but it can also be any other date. The "Modified" date is not always the date where the password was last changed, because there can be other changes in the database (like changes triggered by the KeePassXC browser plugin).
So you need to determine the modification date of the password by analyzing the creation date and checking in the history of the entry when the password was last changed.

This information (when the password was last changed) is also useful for users, so you should make this information transparent to the user.
This is for example useful when the security check tells the user to change the password, so the user can see the reason (when exactly the password was last changed).

The best place would be the page "Properties" (when you edit the entry) because there you already show other related values (like the modification date and the creation date).

But you should also consider adding the column "Password Modified" that is not shown by default and that the user can select to see.
So when searching for all password entries, the user can sort by this column and then see what passwords were last changed and what passwords were not changed for a longer time.

[droidmonkey]

This would be good information to store in the custom data section of an entry.

[wolframroesler]

This would be good information to store in the custom data section of an entry.

But what it people use different KeePass clients, e. g. on their phone? OK, in this case we could look at the history, but old history items may have been deleted due to restricted history size. Any chance to get the password modification date in a 100% reliable way?

[OLLI-S]

@droidmonkey By saying "storing": do you mean where to store the information in the Database?

[droidmonkey]

@OLLI-S yes.

There is no kdbx standard way to represent the date time when the password itself was changed. It doesn't matter what you do, no other client will display the information without modification

[wolframroesler]

Seems like we need something like a "kdbx consortium" to discuss questions like this. For example, if another client decides to also store password modification dates, they should do it in the same way.

[OLLI-S]

There are many (really many) KeePass applications and to have them all on-board will be hard.
I also don't know the relationship between Dominik to this project (if he is friendly or hostile).

[mmcguill]

Hi, sounds like a useful feature.

I'd be happy to add this to Strongbox too. I would suggest we just add it to the standard "Times" element:

<Times>
    <CreationTime>2018-11-11T09:36:34Z</CreationTime>
    <LastModificationTime>2018-11-11T09:36:47Z</LastModificationTime>
    <LastAccessTime>2018-11-11T09:36:47Z</LastAccessTime>
    <ExpiryTime>2018-11-11T09:35:47Z</ExpiryTime>
    <Expires>False</Expires>
    <UsageCount>1</UsageCount>
    <LocationChanged>2018-11-11T09:36:34Z</LocationChanged>
    ...
    <PasswordChanged>2020-02-08T01:23:45Z</PasswordChanged>
</Times>

That should work, remain compatible with other clients, follow the standard KeePass timestamp model/formats and be easily processed by all clients.
-Mark

[droidmonkey]

Good call!

[keepassium]

Mark's proposal nicely fits into the existing format. However, there are two side effects to consider:

• A non-standard tag will be skipped by most other apps — including Dominik's KeePass, or even earlier versions of KeePassXC itself. All password timestamps will be erased by saving the DB in any of these apps.
• Adding a non-standard tag would create an important precedent. There are plenty of other features that would benefit from custom tags (access control lists, anyone?). In a year, we all might have to deal with 15 flavors of .kdbx.

In this context, @droidmonkey's idea (to use the custom data of the entry) has an important advantage: the CustomData will be preserved by any kdbx4-compatible app.

Preserved, but not necessarily updated. If the user changes the password in an older version of KeePassXC — the history changes, but the timestamp remains the same.

To address this, the "new" KeePassXC would still have to verify/update password timestamps when loading the DB. That is, to go through entry's history looking for the password modification. If the history has been truncated, and the password modification timestamp is older than the oldest entry in the history — the timestamp becomes invalid/undefined.

So, even if the password modification timestamp is saved in custom data, its value

1. would have to be derived from the entry's history, and
2. sometimes won't be available.

So we might as well skip the persistence part and simply calculate the timestamp when loading the DB...

[mmcguill]

Interesting points... Couple of responses:

Non standard apps.
There's no real XSD or comprehensively defined set of elements for the KeePass XML format. Here's an early comment from Dominik on the format.

This means any app supporting KeePass must or at least should handle unknown elements and preserve them.
This may or may not be the case, and I'm sure there are quite a few poorly coded apps that will eat unknown or new elements. However I don't think we can be bound or make important design decisions based on the worst offenders.
Which is why if we were to decide to go with this, I think it's preferable that to be in the standard Times element which I think if we were starting from scratch is where it belongs.

Preserved but not necessarily updated
Again this is going to be the case no matter what, you will have poorly coded apps, bugs, older versions etc. This sort of thing should however diminish over time as people update and more apps come to support it.

Calculating from History
I see the attraction, however some people will have history off, or it'll get trimmed over time.

Regarding your point about KeePassXC doing this anyway, I don't think that's so. This is an optional element. No need to back fill it by calculating from history. Just starting setting it moving forward. It would be a nice to have but not necessary to go to extreme lengths to try guess the password modification date from history.

Basically this isn't a mandatory element, there are very few mandatory elements in the format. So it can be set or not, no need to try to come up with a good value for it if you can't figure one out.

Ultimately password modification date/time is an orthogonal feature to Entry History and it seems a little less than ideal to derive it this way. Basically if you're going to go to the trouble of implementing this feature, might as well go the whole hog and give it it's own element or at least independent existence of some sort...

Custom Tags, XKCD's 15 Formats and the original KeePass application
This is a fair point. I fear the only solution is not a technical one but rather organisational as @wolframroesler has said. Worth reaching out to Dominik and KeePass2Android developers and seeing if they have some input here? Perhaps we could get a lightweight consortium/mailing list going for this sort of KeePass interoperability going, so that all KeePass users can benefit.

[keepassium]

I'm sure there are quite a few poorly coded apps that will eat unknown or new elements. However I don't think we can be bound or make important design decisions based on the worst offenders.

Ahem... Here's a few apps that skip unknown timestamp elements: Keepass2android, KeePass, KeePassXC :)

[droidmonkey]

We do not preserve unknown XML elements (outside of custom data and attributes). It would be impossible to preserve them without doing some sort of crazy merge between the XML or dumping all unknown elements into a "errata" storage on each entry/group/db. @keepassium thank you for posting your thoughts, that is a very good writeup of the downsides to introducing a new element anywhere in KDBX.

On a totally unrelated note, we have been tossing around leading a new KDBX5 standard that helps solve a lot of these issues. Don't know if you guys are interested in this at all?

[keepassium]

On a totally unrelated note, we have been tossing around leading a new KDBX5 standard that helps solve a lot of these issues. Don't know if you guys are interested in this at all?

I guess the first challenge would be to get Dominik on board. (I'm not sure about him, but his support forum guys seem very conservative.) If the new standard is not supported by KeePass, it might as well be called KPXC1.

In either case, I am interested, count me in.