[SalesForce] Enforcing CRUD / FLS / Sharing in Apex

You don't need to check every field that you query. The issue really boils down to who manages security for the field -- your app or the admin. With standard objects, the answer is always the admin. With custom objects, it depends on whether the field is user visible and is used by users or whether it is internal and used only by your app. Things like wizard state, Auth state, etc.

The standard example would be something like an app that manages contracts. The text of the contract would be managed by the admin, but something like contract state would be managed by your app.

Because this is fundamentally ambiguous, you can make a false positive document outlining which fields are managed by your app and which are not. The worst thing to do is nothing and let the tester try to guess, as they might not have much time to go through your app and may not understand your app well enough to correctly classify this on their own. So a lot of this is up to you in making the case that you own some objects and not the admin.

Once you have the list of fields you need to check perms for, it doesn't matter whether they are used in WHERE clauses or directly accessed -- you need to make sure that the perms are checked. You can use the ESAPI API which contains helper functions such as updateAsUser(), you can write your own helper functions, or you can do checks centrally in your controller.

Triggers run after other code or the UI already allows an operation, so the trigger wouldn't fire if the user didn't have permission already, assuming all the upstream checks are made when necessary. Therefore triggers that only update the object being modified generally don't need a check, the issue is if the the trigger modifies some other object, in which case you do need to do the check if the object is managed by the admin.

For background/async/scheduled jobs, there is absolutely no difference in security requirements for async apex versus synchronous apex. Whether you do an operation synchronously or not has nothing to do with whether the admin's policies need to be respected. The same concerns apply as above -- do the check if you don't own the object and don't do it if you do.

One thing to keep in mind here is that unlike sharing, you generally control the profiles and permission sets of your users as you can package these with your app. So package the permissions so that your checks always return true. Then, if your checks return false, it means that the admin assigned a different perm set or changed the perm set assignment for a user of your app, which is something that should generally result in a failure message. There may be situations in which the app should not work for a user -- say the admin removed some perms from that user, but due to not having deep knowledge of how your app works, did not remove that user from your app. Making these checks is exactly for this type of conflict situation, and generally you want to stop processing with an error message and let the admin resolve the inconsistency at the perm level, rather than trying to guess what the admin would want to do and then override the org perms. This is because if every app overrode the org perms, then the admin wouldn't be able to manage permissions centrally anymore.

@TPEHEP,

If you are using a drill-down to navigate to the detail page, I don't think there is a way to disable the hyperlinks dynamically, you need to handle the CRUD/FLS in the list view / parent component where the record is displayed a.k.a hide the record when user don't have access. However, if you must display the record in the parent component, you should create a custom lightning component that displays valid message / record details based on user's FLS. Update your detail record layout to use this custom component.