confusion about distributed systems security-:

[shivajikobardan]

[quote]in a distributed system,users can have different user identifications on different machines. this can allow users to access files that they should not and prevent users from accessing files that they are authorized to access.[/quote]

I really don't understand this. So this is pretty interesting. 

It isn't even "anyone can access anything" instead it is sth else. i.e  "everyone is randomly accessing something". How does this happen? Please tell.

this is taken from this book-:

[Marius Gunnerud]

I think what the writer is trying to get at is that securing a distributed system implementation is difficult and needs to be planned and architected carefully.  This is because the database is spread across multiple systems and there might be users / administrators of one of those systems that has full admin rights to the system, but should not have access to some of the files that are part of the distributed system.  But since the user has admin access to that particular system, and if there are no security measures in place, then that user will also have access to the files and / or processes that are used by the distributed system.

Which book is the screenshot from?