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- <01GG7DV0JUDCAEL196@vax2.cstp.umkc.edu>; Thu, 6 Feb 1992 16:14 CST
- Received: by nixon.llnl.gov (5.57/1.15) id AA14093; Thu, 6 Feb 92 14:11:16 -0800
- Received: by (4.1/SMI-4.1) id AA17189; Thu, 6 Feb 92 14:06:14 PST
- Date: Thu, 6 Feb 92 14:06:14 PST
- From: karyn@cheetah.llnl.gov (Karyn Pichnarczyk)
- Subject: CIAC Bulletin C-15: Michelangelo Virus on MS DOS Computers
- To: external@cheetah.llnl.gov
- Message-id: <9202062206.AA17189@>
-
-
- NO RESTRICTIONS
- _____________________________________________________
- The Computer Incident Advisory Capability
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- Information Bulletin
-
- Michelangelo Virus on MS DOS Computers
-
-
- February 6, 1992, 1400 PDT Number C-15
- _________________________________________________________________________
- Name: Michelangelo virus
- Platform: MS-DOS computers
- Damage: On March 6 will destroy all files on infected disks and
- diskettes that are accessed.
- Symptoms: CHKDSK reports "total bytes memory" 2048 bytes less than
- expected
- Detection: DDI Data Physician Plus! v 3.0C, FPROT 2.01, other
- anti-viral packages updated since late September 1991
- Eradication: DDI Data Physician Plus! v 3.0C, FPROT 2.01, other
- anti-viral packages updated since late September 1991
- _________________________________________________________________________
- Critical Facts about Michelangelo Virus
-
- The Michelangelo virus, one of the most widespread viruses among MS
- DOS systems, infects the Master Boot Record of hard disks and the boot
- sector of floppy disks. This virus will destroy infected disks on
- March 6 (Michelangelo's birthday). It infects very rapidly and
- quietly, usually showing no indication of its presence until a virus
- detection utility notes its existence.
-
- Infection Mechanism
-
- This virus is very similar to the Stoned family of viruses (see CIAC
- Bulletin A-28 for a description of the Stoned virus). When a
- Michelangelo-infected diskette is placed in the A: drive and the
- machine is booted, the virus is loaded into memory from the infected
- floppy disk. It then quickly infects the machine by moving the hard
- disk's original boot sector to another location on the disk, and
- installs itself as the boot sector. From then on, any access to
- another disk spreads the virus to that disk. The disk which infects
- the hard disk does NOT have to be a bootable system diskette to spread
- the infection. Also, all boot infector viruses, such as this one, do
- NOT affect user files, therefore, a backup prior to eradication will
- enable full recovery of all user data and programs.
-
- Potential Damage
-
- On March 6 of any year this virus will destroy all data on any disk
- from which the machine is booted. This occurs by overwriting hard
- disk sectors 1-17, heads 0-3, tracks 0-255, or the entire diskette
- with random characters, thus making recovery questionable at best.
- Note that if your hard disk is partitioned and contains another
- operating system, such as UNIX, in the area overwritten, that data
- will be destroyed as well. On all other days of the year this virus
- lays dormant, merely copying itself to other disks. The infection
- mechanism of this virus may also cause read errors to occur upon some
- high density (1.2 M) diskettes.
-
- A problem can occur if a disk is infected by both the Michelangelo and
- the Stoned viruses AT THE SAME TIME. Both move the 'original' boot
- sector to the same location on the disk, so when the second infection
- occurs, the original clean boot sector is destroyed by being
- overwritten by the first virus. CIAC recommends a low-level format of
- the disk if this double-infection occurs, although performing the
- DOS SYS operation may repair a damaged diskette, and performing the
- undocumented FDISK/MBR operation (in DOS 5.0 only) may repair a
- damaged hard disk.
-
- Detection and Eradication
-
- Because the Michelangelo virus has been discovered relatively
- recently, only anti-virus products updated since early autumn of 1991
- will detect it. If you suspect your PC has this virus and do not have
- an updated version of a virus scanner, running CHKDSK will report a
- "total bytes memory" value 2048 bytes less than expected. For
- example, a PC with 640 KBytes of memory will normally return a value
- of 655,360 bytes, with Michelangelo that value would be 653,312. Of
- course, having less "total bytes memory" does not necessarily mean a
- virus is resident on your machine, as some valid memory resident
- programs can affect this value as well.
-
- CIAC is aware of at least two publicized cases of this virus being
- inadvertently distributed by vendors. The vendors involved are
- Leading Edge and DaVinci Systems; both vendors have made an attempt to
- contact all recipients of the software involved.
-
- CIAC stresses the importance of checking all incoming diskettes with
- an anti-viral utility, such as VIRHUNT from DDI's Data Physician Plus!
- package. CIAC recommends that once a system has had a virus
- eradicated, it be powered down. The computer should then be observed
- closely throughout the entire boot-up process. Another virus scan
- should be performed on the machine to ensure that it is devoid of any
- virus.
-
- For additional information or assistance, please contact CIAC:
-
- Karyn Pichnarczyk
- (510) 422-1779 or (FTS) 532-1779
- karyn@cheetah.llnl.gov
-
- (FAX) (510) 423-8002 or (FTS) 543-8002
-
- Send e-mail to ciac@llnl.gov or call CIAC at
- (510)422-8193/(FTS)532-8193.
-
- PLEASE NOTE: Many users outside of the DOE and ESnet computing
- communities receive CIAC bulletins. If you are not part of these
- communities, please contact your agency's response team to report
- incidents. Some of the other teams include the NASA NSI response
- team, DARPA's CERT/CC, NAVCIRT, and the Air Force response team. Your
- agency's team will coordinate with CIAC.
-
- Neither the United States Government nor the University of California
- nor any of their employees, makes any warranty, expressed or implied,
- or assumes any legal liability or responsibility for the accuracy,
- completeness, or usefulness of any information, product, or process
- disclosed, or represents that its use would not infringe privately
- owned rights. Reference herein to any specific commercial products,
- process, or service by trade name, trademark manufacturer, or
- otherwise, does not necessarily constitute or imply its endorsement,
- recommendation, or favoring by the United States Government or the
- University of California. The views and opinions of authors expressed
- herein do not necessarily state or reflect those of the United States
- Government nor the University of California, and shall not be used for
- advertising or product endorsement purposes.
- $