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                            VIRUS REPORT         
                             dBASE Virus         
                    

Synonyms: DBF virus

Place of Origin: New York.

Host Machine: PC compatibles.

Host Files: Remains resident. Infects COM files and overlay files. May
infect EXE files.

Increase in Size of Infected Files: 1864 bytes.

Nature of Damage: Corrupts DBF files. Affects system run-time operation.
Corrupts program or overlay files.

Detected by: Scanv47+, F-Prot, IBM Scan, Pro-Scan.

Removed by: CleanUp, Scan/D, or F-Prot.

     Discovered by Ross Greenburg of New York, this is a memory resident
.COM/.OVL virus, which attempts to infect the dBASE program. When an
infected application is executed, the virus installs in memory, looking
for an open operation on .DBF files. Any writes to this file have two
bytes transposed at random. The virus keeps track of which files and
bytes have been altered using a file called BUG.DAT in the same directory
as the .DBF files. Reads of data are corrected by the resident portion of
the virus, thus data appear correct. However, when BUG.DAT is 90 days
old, the virus overwrites/nulls the root directory and FAT structures. 
If the DBF file can be recovered, it will be recovered with non-obvious
errors.

     After this virus has been detected, if you remove the infected DBase
program and replace it with a clean copy, your DBF files that were opened
during the period that you were infected will be useless since they are
garbled on the disk even though they would be displayed as expected by
the infected Dbase program. To avoid file damage, keep multiple backups,
and keep hard copy of your transactions. Running a program such as
Deskview will permit you to look in your dBASE directory for BUG.DAT
during dBASE operations.


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  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.                                       
                                                                    
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            The document is copyright (c) 1990 NCSA.                
                                                                    
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