Re: base64

From: Alexander Ogol (sanyok_nospam_at_prophysoft.org.ua)
Date: 09/23/03

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Date: Tue, 23 Sep 2003 19:50:56 +0300

    >>>>> "IT" == Ilya Teterin writes:

    [kham-kham-kham....argh....]

     IT> How to solve this issue? I believe we should rewrite at least
     IT> filtering systems to block malformed base64-encoded data because we
     IT> don't know is it malicious or not. Otherwise, we can meet new powerful
     IT> e-mail worm.

    Rewriting filtering systems for rejecting malformed mail couldn't be good
    decision in all situations. Some mailing lists (debian-russian, for example)
    add some 7bit information after letter body while re-forwarding, regardless
    of was the letter base64/QP encoded or not, resulting of such malformed
    mail (and if your mail server recodes all 8bit mail to base64, you have no
    way to write to those mail lists without creating malformed mail at
    result).
    So I think that the right solution (before antivirus software would be
    rewritten) is to write filters by yourself - decode base64 as that do
    popular mail clients and give them to antivirus.
    Of course, it's somehow more hard than just filtering up all those
    letters. 

    -- 
Sincerely yours, Alexander Ogol, happy GNU/Linux user.
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