Security Scanners and other Auditing Tools [was Re: ISS Internet

From: A. C. Eufemio (anthony_eufemioat_private)
Date: Tue Feb 09 1999 - 13:19:40 PST

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    > If ISS claims to check for the ioslogon bug, but actually checks (by
    > whatever means) for software versions known to have that bug, the
    claim
    > is a lie.
    
    I would not go as far as saying that it is a lie.  It's just dubious and
    just gives the security auditor inadequate data during the audit
    process.
    
    > If you claim to check for the ioslogon bug, then that's what
    > you should do: try to exploit it and see if it works.  Who knows,
    maybe
    > there's another vulnerable version out there, or perhaps some
    > supposedly vulnerable versions don't happen to be vulnerable after
    all.
    >
    
    All security scanners and intrusion testing software should actually
    exploit
    the vulnerability that they are testing for to determine if it is
    actually
    vulnerable.  Audit reports should not be generated using security
    audit tools
    that only check for vulnerabilities based on the version number and
    patch
    levels but instead use this information generated by tools like ISS,
    strobe,
    COPS, NetRanger, etc. as a guideline as to what resources need further
    testing
    and investigation.  The reason for this is that there may be some
    security
    program that might actually prevent vulnerability exploitation from
    happening.
    A good example of such security program is SeOS Access Control for
    UNIX.  This
    product is used by many big companies to protect specified resources
    even if UNIX
    permissions allow access and it can also protect the resources from
    root.  With
    this in mind one can use a security auditing tool to check for the
    vulnerability
    by relying upon the version number of the operating system and the
    patch level
    it has and it could potentially identify resources as being vulnerable
    even if in
    fact the resources have an added layer of protection that the security
    scanner does
    not recognize because it is not part of the native operating system's
    security.
    
    For more information about SeOS Access Control and SECURED check out
    http://www.memco.com/ there is also a product that prevents stack
    overflow exploitation on several UNIX platforms.
    
    > I can't remember offhand what this bug does.  If it's a "hang your
    > router" sort of thing, you may want to have *two* tests, potentially
    > independently controllable, "check for ioslogon bug (dangerous, may
    > crash your router)" and "check for software versions known to have
    > ioslogon bug (safe, requires SNMP)".  But claiming to check for the
    bug
    > when actually just checking the software version (via a means which
    can
    > be disabled without closing the bug, no less) is like a spamfighter
    > saying "your SMTP daemon claims to be an old Sun sendmail, therefore
    > you're an open relay": it's checking for the wrong thing
    
    
    
    >> OK, so maybe you can explain just exactly how we're supposed to find
    >> out whether it is vulnerable if it won't talk to us?
    
    Perhaps actually exploiting the bug would tell you if the system is
    vulnerable.
    
    ==
    -=-=-=-=-=-=-=-=-=-=-=-=-=-
         Anthony C. Eufemio
     anthony_eufemioat_private
    -=-=-=-=-=-=-=-=-=-=-=-=-=-
    
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