ISS Security Brief: "Mimail" Mass-Email Worm Propagation

From: X-Force (
Date: 08/01/03

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    Internet Security Systems Security Brief
    August 1, 2003

    "Mimail" Mass-Email Worm Propagation


    ISS X-Force has detected the spread of a mass-emailing worm named
    "Mimail". The Mimail worm is currently propagating aggressively across the
    Internet. Mimail takes advantage of a vulnerability in Internet Explorer
    to hide an executable program within what appears to be a benign HTML file
    delivered to recipients via email.


    The executable payload of the worm is hidden within a HTML file that is
    delivered in a compressed ZIP archive. Many Internet users believe that
    HTML files are not dangerous. The Mimail worm was designed specifically to
    appear to be benign, and to execute via a flaw in Internet Explorer.
    Viruses or worms that propagate by exploiting flaws in software are
    particularly dangerous, and they generally propagate more effectively.

    For the complete ISS X-Force Security Alert, please visit:

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