RE: Vulnebrability level definition

From: Damir Rajnovic (gausat_private)
Date: Thu Feb 13 2003 - 02:43:32 PST

  • Next message: James Chamier: "Mac OS X Server"

    At 13:33 12/02/2003 -0500, Rob Shein wrote:
    >I disagree.  The question isn't the severity of the compromise, but rather
    >the severity of the vulnerability.  Many factors come into this, such as the
    >ease of exploitation and frequency of attempted exploitation.  A good
    
    The vulnerability of a product must be put into a perspective of your
    organization. My guess that the whole point of this rating is so that
    customers can prioritize their work an decide if they need to apply
    the patch (or the workaround) right now or it can wait until the next
    week. Is that so or not? If it is so, then you also must take into
    account where and how you are using that vulnerable product. If you
    are using this product as a part of your critical infrastructure then
    you may have 1:1 mapping of the advisory rating and importance to you.
    If you are mixed environment and using many different products then
    it is not that straightforward. Yes, a vulnerability may be grave by 
    itself but, the way how you use this product may mitigate the danger. 
    
    >example of a severe bug would be the unicode exploit on IIS; no firewall can
    >mitigate it (without voiding the point of the web server), anyone with a
    >browser can exploit it (no need to know offsets or write shellcode, it's the
    
    You are assuming that IIS is the one running a publicly accessible
    server. If IIS is used in some remote office deep within you organization
    then it is less exposed. Thus, one may not rush to patch this vulnerability
    but wait some time.
    
    >In risk management, we think in terms of likelihood of occurrence and impact
    >of event.  Certain vulnerabilities are more likely to be exploited than
    >others, and some are worse than others, so these factors need to be
    >considered before someone can even begin to try to manage the risks.
    
    Agreed. There are few examples where a vulnerability may look like a hard
    to exploit until someone make a script. I do not know how many vendors
    will go back and update their rating. Even worse, how many customers
    would know that the rating has been changed? Anyway, you are applying
    information about the vulnerability to your environment and then making
    decisions how relevant and important it is to you. This is something
    that only you can do. Vendor can not do that for you.
    
    Anyway, my point is that severity of the vulnerability is not
    automatically the priority of how fast you need to apply fixes. For
    that reason I do not believe that assigning severity to an advisory
    gives you much. The advisory must contain enough information that will
    enable you to make your own decision how severe it is in your
    environment. 
    
    Gaus
    ==============
    Damir Rajnovic <psirtat_private>, PSIRT Incident Manager, Cisco Systems
    <http://www.cisco.com/go/psirt>      Telephone: +44 7715 546 033
    200 Longwater Avenue, Green Park, Reading, Berkshire RG2 6GB, GB
    ==============
    There are no insolvable problems. 
    The question is can you accept the solution? 
    
    
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