Original issue date: February 6, 1992<BR> 
Last revised: September 19, 1997<BR>
Attached copyright statement

<P>A complete revision history is at the end of this file.


<P>The CERT Coordination Center has received information concerning a
personal computer virus known as Michelangelo.  The virus affects IBM
PCs and compatibles.  A description of the virus, along with suggested
countermeasures, is presented below.


<H2>I. Description</H2>

<P>The Michelangelo virus is a computer virus that affects PCs running
MS-DOS (and PC-DOS, DR-DOS, etc.) versions 2.xx and higher.  Note,
however, that although the virus can only execute on PCs running these
versions of DOS, it can infect and damage PC hard disks containing
other PC operating systems including UNIX, OS/2, and Novell.  Thus,
booting an infected DOS floppy disk on a PC that has, for example,
UNIX on the hard disk would infect the hard disk and would probably
prevent the UNIX disk from booting.  The virus infects floppy disk
boot sectors and hard disk master boot records (MBRs).  When the user
boots from an infected floppy disk, the virus installs itself in
memory and infects the partition table of the first hard disk (if
found).  Once the virus is installed, it will infect any floppy disk
that the user accesses.

<P>Some possible, though not conclusive, symptoms of the Michelangelo
virus include a reduction in free/total memory by 2048 bytes, and some
floppy disks that become unusable or display &quot;odd&quot; graphic
characters during &quot;DIR&quot; commands.  Additionally, integrity
management products should report that the MBR has been altered.

<P>Note that the Michelangelo virus does not display any messages on
the PC screen at any time.

<H2>II. Impact</H2>

<P>The Michelangelo virus triggers on any March 6.  On that date, the
virus overwrites critical system data, including boot and file
allocation table (FAT) records, on the boot disk (floppy or hard),
rendering the disk unusable.  Recovering user data from a disk damaged
by the Michelangelo virus will be very difficult.

<H2>III. Solution </H2>

<P>Many versions of anti-virus software released after approximately
October 1991 will detect and/or remove the Michelangelo virus.  This
includes numerous commercial, shareware, and freeware software
packages.  Since this virus was first detected around the middle of
1991 (after March 6, 1991), it is crucial to use current versions of
these products, particularly those products that search systems for
known viruses.

<P>The CERT/CC has not formally reviewed, evaluated, or endorsed any
of the anti-virus products.  While some older anti-virus products may
detect this virus, the CERT/CC strongly suggests that sites verify
with their anti-virus product vendors that their product will detect
and eradicate the Michelangelo virus.

<P>The CERT/CC advises that all sites test for the presence of this
virus before March 6, which is the trigger date.  If an infection is
discovered, it is essential that the user examine all floppy disks
that may have come in contact with an infected machine.

<P>As always, the CERT/CC strongly urges all sites to maintain good
backup procedures.


<P>The CERT/CC wishes to thank for their assistance: Mr. Christoph
Fischer of the Micro-BIT Virus Center (Germany), Dr. Klaus Brunnstein
of the Virus Test Center (Germany), Mr. A. Padgett Peterson, P.E., of
the Technical Computing Center at Martin-Marietta Corp., and Mr. Steve
R. White of IBM's Thomas J. Watson Research Center.

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<P>Copyright 1992 Carnegie Mellon University.</P>


Revision History
September 19,1997  Attached copyright statement