旼컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � VIRUS REPORT � � 123nhalf � 읕컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date of Origin: September, 1989. Host Machine: 80286-based micros. Host Files: 123DOS.EXE Increase in Size of Infected Files: 3907 bytes. Nature of Damage: removes 1/2 of rows, columns in 1-2-3 ver. 3 spreadsheet file. This virus was so named because it causes a Lotus 1-2-3 release 3 spreadsheet to be saved exactly one half the size it should be. The 123DOS.EXE file grows in size (one time) by 3907 bytes. Any spreadsheet saved after the virus has infected the file is exactly half the size of what it should be. If the 123DOS.EXE file is erased and restored from a backup, and 1-2-3 is run again, the file again grows in size. This virus will only infect the 123DOS.EXE file, when running on a machine with a '286 processor. it will not infect the file on a '386 system. The virus also will not infect files unless there is a minimum of 3 megabytes of extended memory. Expanded memory does not matter and does not come into the picture. Something is missing from our current understanding of this virus: if the virus infects only 123DOS.EXE, how do you get it? How would it spread? (Why, that is, would an infected copy of 123DOS.EXE ever find itself running with access to an uninfected copy; why would there ever be two different copies of the file on the same machine?). It is possible that the virus spread through the disks during production, or that it comes in with other software, and looks for 123DOS.EXE. 123SCAN.EXE detects the 123nhalf virus. �袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴� � This document was adapted from the book "Computer Viruses", � � which is copyright and distributed by the National Computer � � Security Association. It contains information compiled from � � many sources. To the best of our knowledge, all information � � presented here is accurate. � � � � Please send any updates or corrections to the NCSA, Suite 309, � � 4401-A Connecticut Ave NW, Washington, DC 20008. Or call our BBS � � and upload the information: (202) 364-1304. Or call us voice at � � (202) 364-8252. This version was produced May 22, 1990. � � � � The NCSA is a non-profit organization dedicated to improving � � computer security. Membership in the association is just $45 per � � year. Copies of the book "Computer Viruses", which provides � � detailed information on over 145 viruses, can be obtained from � � the NCSA. Member price: $44; non-member price: $55. � � � � The document is copyright (c) 1990 NCSA. � � � � This document may be distributed in any format, providing � � this message is not removed or altered. � 훤袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴暠 5 Downloaded From P-80 International Information Systems 304-744-2253