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- *** Reports collected and collated by ***
- *** PC-Virus Index ***
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- *** to the authors ***
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-
- PIXEL (V-847) aka AMSTRAD VIRUS
- ===============================
-
- This virus was imported into Bulgaria by a foreign student from
- Greece, where it had been around since it was published in the April
- 1987 edition of PIXEL magazine, as an example of a virus program. It
- was written by a local computer wizard known as Nick the Greek.
-
- Three months later the magazine published an 'antibiotic', claiming
- that release of the disinfector had been delayed so that readers
- could set up a few practical jokes.
-
- The virus is supplied as a program in BASIC, which when run creates
- a COM-file which in fact contains the real virus.
-
- The virus is extremely stupid. It infects only .COM-files in the
- current directory of the current drive. However, it infects ALL
- these files at once. The only way to spread the virus is to run an
- infected file when one of the directories listed in the PATH
- variable is current. Then each time a file from this directory is
- run, all files in the current directory will get infected.
-
- The virus is not memory resident. It becomes active only when an
- infected file is run.
-
- The virus prepends itself in front of the infected files and their
- size increases by 847 bytes, most of which is garbage.
-
- Each infected file contains the generation number of the virus.
-
- There are no effects before the 5th generation. After the 5th
- generation, however, when an attempt is made to execute an infected
- file, the probability of success is only 1/2 (the lowest bit of the
- system timer is used as a random number generator).
-
- If the program refuses to load, a message is displayed:
-
- "Program sick error: Call doctor or buy PIXEL for cure description"
-
- and the program will terminate.
-
- This original virus has been modified and there are now several
- versions known in Bulgaria and elsewhere.
-
- * The first has been optimized and is only 345 bytes long. (See
- V-345)
-
- * The second has been optimized even further and has a length of
- only 299 bytes. (See V-299).
-
- The AMSTRAD variant which carries a false advertisement for AMSTRAD
- computers is believed to have originated in Portugal.
-
- There are now many variants. A decsription of one follows:
-
-
- ====== Computer Virus Catalog 1.2: "V-345" Virus (11-June-1990) ======
- Entry.................. "V-345" Virus
- Alias(es).............. ---
- Strain................. Amstrad Virus Strain
- Detected: when......... Winter 1989
- where........ Bulgaria
- Classification......... Program virus, direct action, prefix
- Length of Virus........ 345 bytes
- ------------------------ Preconditions -------------------------------
- Operating System(s).... MS-DOS
- Version/Release........ 2.xx and upward
- Computer models........ IBM-PC's and compatibles
- -------------------------- Attributes --------------------------------
- Easy identification.... The virus contains the string "Program sick
- error:Call doctor or buy PIXEL for cure
- description". The virus identifies
- infection by checking for the string "IV"
- at offset 3 in the COM file.
- Type of infection...... A program virus that infects all COM files
- in the current directory by prepending
- itself to its victim. The virus will not
- spread very quickly.
- Infection trigger...... As it is a direct action virus, it will
- only infect on run-time, but will do this
- at any time.
- Media affected......... Any logical drive that is the "current" drive
- Interrupts hooked...... ---
- Damage................. Denial of access
- Damage trigger......... The virus carries an evolution counter that is
- increased every time the virus is executed.
- When the counter is above or equal to 5,
- the virus reads the system timer. If the
- value is odd, the virus will terminate
- with the message described above. (This is
- effectively a 50% chance of termination.)
- Particularities........ This is an optimized variant of Amstrad virus
- Similarities........... Amstrad, V-299, Cancer Viruses
- ---------------------------- Agents ----------------------------------
- Countermeasures........ Checksumming programs will detect the changes
- to the files.
- - ditto - successful.. V847clr by Vesselin Bontchev will successfully
- search and clear the Amstrad, V-345 and
- V-299 viruses, and find the Cancer virus.
- Standard Means......... Believe it or not, write protecting programs
- with ATTR will prevent the virus from
- spreading to them.
- ----------------------- Acknowledgements -----------------------------
- Location............... Bulgarian Academy of Science and
- University of Hamburg, Virus Test Center
- Classification by...... Morton Swimmer
- Documentation by....... Vesselin Bontchev
- Date................... 11-June-1990
- Information source..... ---
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