Re: Fwd: CERT Advisory CA-2000-02

From: Henrik Nordstrom (hnoat_private)
Date: Sat Feb 05 2000 - 03:13:55 PST

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    Marc Slemko wrote:
    
    > Also note that filtering or encoding things is not as easy as you may
    > think.  There are far too many very annoying things, including characterset
    > issues and browser specific extensions.
    
    It is if you only accept ASCII/ISO-8859-1(or another defined character
    class) with some simple markup extensions. The markup extension could be
    a small strict subset of HTML, or a completely different one.
    
    I do not understand why everyone claims that sanitizing HTML content is
    that hard. For most applications where it is needed, the fancy features
    of HTML simply isn't needed. If your are reading email, then it does not
    matter much if the layout does not match to 100% of what the original
    author intended, as long as the information content is properly
    presented and you know that you safely can view the content.
    
    For the case of publishing information on a shared web site using strict
    HTML filterin is also beneficiable as it forces all authors to use a
    common HTML dialect, guaranteed not to disturb the site enforced layout
    or presentation, and helps keeping the information authors on track for
    providing the information rather than fiddling around to much in layout
    or presentation details. If you question the validity this approach to
    information processing, take a visit to your closest larger news paper
    and study the flow of information there.
    
    You need to take separate views on information and layout. The two are
    quite separate from each other. Defining a strict syntax for information
    isn't hard, doing so for HTML layout not using pre-defined style-sheets
    is a tricky issue.
    
    --
    Henrik Nordstrom
    



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