Re: Proposal "LUID": CAPP requirements

From: allbery@kf8nh.apk.net
Date: Mon Apr 17 2000 - 17:50:09 EDT

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    On 17 Apr, Jan Harkes wrote:
    +-----
    | On Mon, Apr 17, 2000 at 08:26:33AM -0700, Linda Walsh wrote:
    | > These are some basics from CAPP that may explain
    | ...
    | > events which occur within the system. The CAPP provides for a level of
    | > protection which is appropriate for an assumed non-hostile and well-managed
    | > user community requiring protection against threats of inadvertent or
    | > casual attempts to breach the system security.
    | ...
    |
    | LUIDs are not very useful for these stated goals because;
    |
    | 1- They don't keep track of people who managed to breach security by
    | _avoiding_ the identification and authorization steps.
    +--->8

    Hm. CAPP appears to have altered goals from C2: C2 was to detect
    *internal* security breaches on an assumed-externally-secure system,
    and indeed its auditing provisions are not suitable for detection of
    external threats.

    If CAPP truly targets external threats, then I think we should indeed
    bypass it as a completely misdesigned system for such.

    | 2- if the perpetrator recovers a password (sniffing/social-engineering/
    | rubber-hose tactics), his actions are indistuiguishable from those
    | made by the real user.
    +--->8

    True, but there's no solution to this problem anyway.

    | Well, your authorization is not my authorization. Someone can be logged
    | in but not authorized as far as kerberos and Coda are concerned. The
    +--->8

    That's part of my first comment: C2, from which CAPP is descended,
    explicitly *does not cover* networked systems. Not even
    "intranet"-connected systems. C2 would need a major reworking to even
    begin to address such.

    I am starting to agree that CAPP is a trainwreck....

    I will concede the point about LUIDs per se; it looks like CAPP has
    generalized them somewhat. However, keep in mind that the more complex
    the mapping of a user identity, the more suspect it is from an auditing
    standpoint.

    | the right granularity for reliable audits. Maybe it then becomes close
    | enough to the AFS PAG concept that Coda can use it for it's user-subject
    | identity binding as well.
    +--->8

    You still disallow multiple security contexts (PAGs) within a single
    user session with such a design, whereas PAGs were designed
    specifically to support them. You *should not* restrict PAGs to
    implement this; you want a different identity mechanism.

    -- 
    brandon s. allbery	   os/2,linux,solaris,perl	allbery@kf8nh.apk.net
    system administrator	   kthkrb,heimdal,gnome,rt	  allbery@ece.cmu.edu
    carnegie mellon / electrical and computer engineering			kf8nh
        We are Linux. Resistance is an indication that you missed the point.
    

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