Re: Strange hidden messages in email

From: Michal Zalewski (lcamtufat_private)
Date: Fri Apr 26 2002 - 11:02:55 PDT

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    On Fri, 26 Apr 2002, Jim Cockerham wrote:
    
    > Below is a copy of the source from one of the messages , The actual
    > message viewable in Outlook express was just a simple
    > link.................
    
    The most obvious purpose of such hidden tags is to bypass anti-spam
    filtering software that, say, redirects a mail to /dev/null once enough
    words like "best", "opportunity", "deal", "click", etc are found in the
    body. Some spammers also use neatly obfuscated JavaScript that writes the
    actual message - but the latter is relatively easy to filter out.
    
    Quite recently, spammers seem to be really interested in being as
    obtrusive as possible. The trick itself is not new, but wasn't very
    popular nor exploited by "respectable" spammers (just had to use this
    phrase) few years ago - but now, it is a real problem. This is a sad
    tendency, probably caused by a very rapid increase in the spam volume
    (wasn't that something like 900% a year?) - it takes more and more to be
    visible. I guess they do not really believe a guy who put some effort in
    filtering out the spam will respond to their offer if only they manage to
    bypass the rules he's using - I think they are targeting anti-spam filters
    set up for whole corporations, mailing lists, user groups.
    
    -- 
    _____________________________________________________
    Michal Zalewski [lcamtufat_private] [security]
    [http://lcamtuf.coredump.cx] <=-=> bash$ :(){ :|:&};:
    =-=> Did you know that clones never use mirrors? <=-=
              http://lcamtuf.coredump.cx/photo/
    
    
    
    
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