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RE: audit 0.6 release



--- Leigh Purdie <Leigh Purdie intersectalliance com>
wrote:

> But that raises the question I guess.. If a user
> attempts to
> access /path/to/protected/file.txt, and ACLs block
> them at /path/to,
> what should the event report?

In existing (Solaris, Irix) audit systems you
will get
    - The access attempted (e.g. open for read, stat)
    - The process attributes
    - The path requested, /path/to/protected/file.txt
    - The path resolved, /path/to
    - The attributes of /path/to that resulted in
      access being denied (the ACL in this case)

It is amazingly common that the path requested
is not the path that ends up being interesting
in audit records.

> Failed access
> to /path/to/protected/file.txt (at which point, the
> auditor wants to
> know 'how did they get that far in the directory
> tree??), or Failed
> access to /path/to (at which point, the auditor has
> no idea of an
> attempted attack on a 'sensitive file')?

This is why both are necessary.
 
> My feeling is that the second option is most useful,
> but if we follow
> the above logic to conclusion, perhaps we would
> receive both events.

Meeting the CAPP requirements as well as being
useful to an auditor adds a certain spice to the
design.

> >     - When /etc/passwd is renamed to /etc/opasswd
> >       do you want to stop watching it?
> 
> Yes. I don't think we should second-guess the intent
> of the auditor. If
> they request /etc/passwd, monitor that only. If they
> request /etc/*passwd*, that's a different story. 

The CAPP requirements are written in subject/object
terms. The object that was /etc/passwd is now named
/etc/opasswd. To meet the CAPP requirements you need
a way to monitor the object, even if the name
changes.

Pathnames aren't even attached to the objects.
A file can exist without one, and still needs to
be audited even when there is no reference to it
in the file system namespace. Really.


=====
Casey Schaufler
casey schaufler-ca com


		
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