85 lines
4.2 KiB
Plaintext
85 lines
4.2 KiB
Plaintext
ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿
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³ VIRUS REPORT ³
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³ Palette Virus ³
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ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ
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Synonyms: Zero Bug virus, 1536 virus
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Date of Origin: September, 1989.
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Place of Origin: The Netherlands
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Host Machine: PC compatibles.
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Host Files: COM files. Memory resident.
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Increase in Size of Infected Files: 1536 bytes.
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Detected by: Scanv38+, F-Prot.
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Removed by: Scan/D, F-Prot, or delete the infected files.
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Scan Code: EB 2B 90 5A 45 CD 60 2E C6 06 25 06 01 90 2E 80 3E 26 06 00 8D
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3E 08 06 0E 07 75 5E 2E C6 06 26 06 05 90.
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This virus infects .COM files, causing them to grow by 1536 bytes,
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but its main mission is to infect the copy of COMMAND.COM that is pointed
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to by the environment variable COMSPEC. If COMSPEC does not point to
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anything useful, the virus will install itself as a resident extension,
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taking over INT 21h.
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From the moment the virus has infected COMMAND.COM or has installed
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itself as a TSR, the virus will intercept DOS INT 21h, function calls 11h
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(find first file), 12h (find next file), 57 (get/set file date & time),
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3Eh (close file), 40h (write to file or device) and 3Ch (create file).
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All COM files that are accessed via function calls 3Ch, 3Eh and 40h
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(by DOS itself or from any other program) will be infected by the virus.
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This includes actions like COPY and XCOPY. Any COM file you create by
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yourself via a compiler, linker, DEBUG or EXE2BIN will also be infected.
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The extra 1536 bytes in infected files will not show up when you
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display a directory of your disk. The virus intercepts DOS function
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calls Find First, Find Next and Get/Set file date & time. If a COM file
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found by these DOS functions has been infected by the virus, the
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information in the DTA (Disk Transfer Area) will be changed to show the
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actual filesize minus 1536 bytes. DIR and most full-screen file
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utilities (Like Norton and PCTOOLS) will be fooled by this trick. This
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makes it very hard to detect the virus by simply checking the size of COM
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files, because infected files will show up with their ORIGINAL size!
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If (and only if) the currently loaded COMMAND.COM is infected, the
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virus will also hook the timer interrupt 1Ch. After a while a smiley face
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(ASCII character 01) will move over your screen and "eat" all zeroes it
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can find. Hence the name "Zero Bug" for this virus. The virus does not
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format disks or erase files.
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The virus seems not to be spread very widely and may be rather new.
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ÉÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ»
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º This document was adapted from the book "Computer Viruses", º
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º which is copyright and distributed by the National Computer º
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º Security Association. It contains information compiled from º
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º many sources. To the best of our knowledge, all information º
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º presented here is accurate. º
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º º
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º Please send any updates or corrections to the NCSA, Suite 309, º
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º 4401-A Connecticut Ave NW, Washington, DC 20008. Or call our BBS º
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º and upload the information: (202) 364-1304. Or call us voice at º
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º (202) 364-8252. This version was produced May 22, 1990. º
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º º
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º The NCSA is a non-profit organization dedicated to improving º
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º computer security. Membership in the association is just $45 per º
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º year. Copies of the book "Computer Viruses", which provides º
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º detailed information on over 145 viruses, can be obtained from º
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º the NCSA. Member price: $44; non-member price: $55. º
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º º
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º The document is copyright (c) 1990 NCSA. º
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º º
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º This document may be distributed in any format, providing º
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º this message is not removed or altered. º
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ÈÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍͼ
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