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Text File | 1991-01-21 | 39KB | 998 lines

A description of PC viruses and their symptoms - Jan. '91 This document lists the file viruses recognized by F-PROT at the time of writing. Since new viruses are continually appearing, this document will never be completely up to date. A short description of the viruses follows, but it is far from complete. The .EXE and .COM infecting viruses known by F-PROT are: 217 405 417 440 492 512 --> Number of the beast 516 600 --> Voronezh 696 699 707 800 948 1024 --> Diamond 1049 --> Yankee 1067 --> Ambulance 1075 1226 --> Phoenix 1260 1392 --> Amoeba 1600 2144 2480 2930 --> Traceback 4096 --> Frodo 5120 8-tunes A-204 --> Jerusalem Advent --> Syslock Agiplan AIDS AIDS-2 Alabama Ambulance Amoeba Amstrad Anarkia --> Jerusalem AntiCAD --> Plastique AntiPascal AntiPascal-2 April 1st Armagedon Attention Bebe Best Wishes Black Monday Blood Bulgarian Tiny Burger Cancer --> Amstrad Carioca Casper --> 1260 Cascade Century --> Jerusalem Choinka --> Vienna Christmas in Japan Cookie --> Syslock Dark Avenger --> Eddie DataCrime DataCrime II Datalock dBase December 24th Destructor Devil's Dance Diamond DIR Do-Nothing --> Stupid Doteater Durban Dyslexia Eddie Eddie II Evil --> Phoenix Father Christmas --> Vienna Fellowship Frere --> Jerusalem Fish 6 --> Frodo Flash Flip Frodo Fuck You --> 417 Fumble Fu Manchu Ghost Groen Links --> Jerusalem Guppy Hallöchen Happy --> VFSI Holland Girl --> Sylvia Hymn --> Eddie Icelandic Icelandic II IDF --> Frodo Internal Invader --> Plastique Itavir Jerusalem Jo-Jo Joker Joker-01 July 13th Kemerovo Kennedy Lehigh Leprosy Liberty Lisbon --> Vienna Lozinsky Macho --> Syslock Mendoza --> Jerusalem MG MG-3 MGTU Minnow --> Zero Hunt MIX1 MLTI Monxla --> Vienna Mother Fish -> Whale Murphy Mystic -> Liberty New Jerusalem --> Jerusalem New Vienna --> Vienna Nina Nomenklatura Number of the Beast Old Yankee Oropax Palette --> Zero Bug Parity Payday --> Jerusalem Perfume Phoenix Piter Pixel --> Amstrad Plastique Polimer Pretoria Proud Prudents PSQR (1720) --> Jerusalem Puerto --> Jerusalem Saddam --> Stupid Saratoga --> Icelandic Scottish Murphy --> Superhack Scott's Valley --> Slow Shake Slow Solano --> Dyslexia South African "Friday 13." Stupid Sunday --> Jerusalem Suomi Superhack SVC Sverdlov Svir Sylvia SysLock Taiwan Tenbyte Time --> Vienna Tiny --> Kennedy Tiny Family --> Bulgarian Tiny Traceback TUQ Turbo Kukac V-1 --> see BOOTVIR.TXT for description V2P2 --> 1260 V2P6 --> 1260 Vacsina Vcomm Victor Vienna Virdem Virus-90 Virus-101 --> Virus-90 Virus-B --> South African Voronezh VP W13 Westwood --> Jerusalem Whale Wisconsin XA1 Yankee Doodle --> Vacsina Zero Bug Zero Hunt In addition there may be some recently discovered viruses, which have not yet become available to the author. It must be noted here, that F-PROT will provide some protection against viruses not yet written. The programs in the package will not, however, be able to remove unknown viruses, unless they are minor variants of known viruses. Now, let's have a look at the viruses mentioned above. In some cases the descriptions are very short, perhaps only a couple of lines. This indicates a new virus, which has not yet been fully dissected. In those cases the effects of the virus may be only partially known. The description will be expanded as better information becomes available. 217 This is a small, not very interesting virus from Poland, which only infects .COM files. 405 Unlike most other program viruses, this one will not increase the length of infected programs (unless they are shorter than 405 bytes). It will overwrite the first 405 bytes in the files it infects. As this primitive method causes the destruction of many programs, the virus is easily found, and therefore not a serious threat. The "405" virus will only infect .COM files, but it it unable to recognize a file already infected. 417 This is a simple 417 byte virus from Eastern Europe. The only text message inside the virus are the words "Fuck You". The virus has not been fully analyzed yet. 440 A 440 byte, direct-action .COM infecting virus. Awaiting analysis. 492 This virus from eastern Europe would not be remarkable, if it was not for the fact that it will not work on the 8088 or 8086 processor. The reason is the use of an instruction (PUSH-immediate) which only exist of later-generation processors. The virus only infects COM files. 516 This simple, Russian COM virus is interesting in one way - it is the first virus which does not modify the beginning of the programs it infects. The virus code is located at the end of infected programs, but the jump to the virus is inside the program, not at the beginning, as is usual. 696 This is a simple direct-action Russian COM virus, which has not been analysed yet. 699 This virus adds 699 bytes to the files it infects, but in addition it may add several "garbage" bytes. As a result disinfected files will often not be of exactly the same length as the original file. 707 This a Russian, 707 byte COM virus, which is awaiting analysis. 948 This Russian virus seems related to the Yankee virus, or at least it is identified as "Yankee" by F-DRIVER, although F-FCHK will identify and remove it correctly. It infects EXE and COM files, including COMMAND.COM, which is infected by overwriting, and should be replaced if infected. 1075 This Russian virus does not seem to work on the 8088 IBM-PC I use for testing viruses - infected programs simply hang the machine. The virus seems to be able to infect EXE and COM files, but has not been analysed yet. 1260 This virus is based on the Vienna virus, but the author, Mark Washburn, has made considerable modifications to it. The most significant change is that the virus is now encrypted. As the name indicates, the virus adds 1260 bytes to the files it infects. The first 39 bytes contain a simple decryption routine, similar to the one used by the Cascade virus. There is one important difference, however. A variable number of short (1- or 2-byte) instructions are added between the decoding instructions. The extra instructions do not affect the operation of the virus - they are only placed there in an attempt to prevent virus scanners from using identification strings. This makes it a little harder to detect the virus, but F-FCHK is nevertheless able to do it. Another variant of the virus exists. It is named Casper because of the following text which is found inside the virus. Hi! I'm Casper The Virus, And On April The 1st I'm Gonna Fuck Up Your Hard Disk REAL BAD! In Fact It Might Just Be Impossible To Recover! How's That Grab Ya! <GRIN> The virus will indeed activate on April 1st and try to format the boot sector, with incorrect parameters. The code seems to contain an error, though. The author of the 1260 virus, Mark Washburn, has also written and distributed the V2P2 virus, which is somewhat longer than 1260 virus. His last virus, V2P6 is still longer, and uses a much more complex self-modifying encryption method. F-FCHK will detect the virus, but can not remove it. If your system ever gets infected by this virus, I suggest you contact the author and demand a disinfection program from him. His address is: Mark Washburn 4656 Polk Street NE Coloumbia Heights, MN 55421 USA 1600 According to reports from Bulgaria, the author of this virus is the same as the one who wrote the Nina virus, and inside the 1600 virus the following message can be found: Dear Nina, you make me write this virus; Happy new year! The 1600 virus infects .EXE and .COM files, increasing their length by 1600 bytes, but COMMAND.COM is overwritten. At least some versions of COMMAND.COM will not work if infected, and infected COMMAND.COM files should be replaced, not disinfected. 2144 This Russian virus appears to be related to the Voronezh virus - perhaps having the same author. It is an encrypted COM and EXE infector, which has not been fully analyzed yet, but is reported to have a similar effect as the Sverdlov virus. 2480 This virus is not a serious threat on most systems, as it only spreads if the year is set to 1988. It was found in Finland, and has not yet been reported elsewhere. It only infects .COM files, and as the name indicates, it is 2480 bytes long. 5120 This is one of the largest viruses known, 5120 bytes. It will infect both .COM and .EXE files, selecting one file of each type to infect, when an infected program is run. Parts of the virus seem to have been written in a high-level language, probably compiled BASIC, but the initialization code is written in assembly language. 800 One of the Bulgarian viruses - 800 bytes long. It bears some resemblance to the Dark Avenger. It seems to overwrite directories, but has not been fully dissected yet. 8-tunes Just as most other "music" viruses, this one is from Germany. It infects .COM files as well as .EXE files. When it activates it will play one out of 8 different tunes. The length of the virus code is 1971 bytes. Agiplan This virus was first reported in the German AGIPLAN company, put then it disappeared for nearly two years, until a sample appeared in South Africa. Structurally the virus is similar to the Zero Bug virus, as both add 1536 bytes to the beginning of the programs they infect. The virus will not have any serious effects until it has been active on an infected machine for several months, but then it will start corrupting writes. AIDS This is a long virus, over 12K, written in Pascal, which overwrites the files it infects. It is therefore easily detected, and not a serious threat. AIDS-2 This is a "companion" virus, in the form of a .COM file, which will locate a .EXE file and create a corresponding .COM file, exploiting the fact that DOS will first execute the .COM file, containing the virus. The virus will then later execute the .EXE file. Alabama This virus was first reported in Israel, but a text string inside it says: SOFTWARE COPIES PROHIBITED BY INTERNATIONAL LAW.............. Box 1055 Tuscambia ALABAMA USA. This message will also appear on the screen in a box on the screen one hour after an infected program is run. Like a few other viruses this one cannot be removed from memory by pressing Ctrl-Alt-Del. It will simply fake a "reboot" and remain in RAM. Alabama will only infect .EXE files, increasing their size by 1560 bytes. Unlike most other resident viruses, it will not automatically infect every new program executed. When a program is run, Alabama will instead search for some other program to infect - probably so the program being executed will get the blame. It will only be infected if no uninfected file is found in the current directory. Every Friday the virus will do something odd. It searches for a file to infect as described above, and executes it instead of the file the user was planning to execute. A bit weird ...! One variant of this virus, Alabama-B is also known. It has been distributed in the form of a modified SDIR.COM file, but normally Alabama will not infect .COM files. Ambulance As the name indicates, the ambulance virus displays an ambulance on the screen. It is a 796 byte .COM infecting virus. A related virus, 1067 byte long is also known, but it has not been analyzed yet. Amoeba This is a 1392 byte .EXE and .COM infecting virus, but little is yet known about it. It overwrites the first 1089 bytes of .COM files, placing the original code at the end and then it appends another 303 bytes. The name of the virus is derived from the following text found inside it. SMA KHETAPUNK - Nouvel Band A.M.O.E.B.A The virus was first reported in Indonesia. Amstrad/Pixel This virus is rather interesting. It is a direct-action virus, that will add 847 bytes to the front of any .COM file it finds in the current directory. The virus code is only around 334 bytes, which made it for a while one of the shortest PC virus known. The rest contains zeros and an advertisement for Amstrad computers which is occasionally displayed. Until the virus reaches the 5th generation, no effects are visible, but in generation 5 or later there is a 50% chance that the message will appear. In a variant of the virus the message is different: En tu PC hay un virus RV1, y ésta es su quinta generación. It has been reported that this virus was also published in a Greek magazine named "Pixel" in the form of a BASIC program that would create an infected program when run. This program contained a different message: "Program sick error: Call doctor or buy PIXEL for cure description" A disinfection program, written by the virus author was then published in the next issue of Pixel. Five other variants of this virus are now known, all from Bulgaria. The major difference is in the length - 852, 740, 345, 299 and 277 bytes. The 740 byte variant is also known as 'Cancer'. It seems that some virus writers there are competing with each other to create the shortest possible version of the virus. The shortest variant, with a length of 277 displays a different message, "PARITY ERROR", simulating a hardware failure. AntiPascal Two viruses, probably from Bulgaria, 605 and 529 byt long, designed to corrupt .PAS and .BAK files. They are said to have been written as a revenge against a former employer of the virus author. The viruses are added to the front of infected programs. AntiPascal-2 A group of three viruses, 400, 440 and 480 bytes long, which are similar to the AntiPascal viruses, but somewhat different structurally - for example they add the virus code to the end of the programs they infect, rather than the beginning. April 1. Here we actually have not one virus, but two different viruses, probably written by the same author, somewhere in Israel. One of them infects .EXE files, the other .COM files. The two viruses have the same effect, however. On April 1st an infected computer will display the following message: APRIL 1ST HA HA HA YOU HAVE A VIRUS. The .COM virus is 897 bytes long, but the .EXE virus is a bit longer, 1488 bytes. Those two viruses were later combined into one, called SURIV 3, which evolved into the Jerusalem virus. Armagedon This virus originated in Greece. It is 1079 byte long, infects .COM files, other than COMMAND.COM, by adding itself in front of the original program. This virus has an interesting effect if a Hayes compatible modem is installed in the computer, including dialing the number 081-141. This is the number of the "speaking clock" on the island of Crete. Attention This 394 byte Russian virus gets its name from the string "ATTENTION" which is written near the beginning of infected files. Like most of the other recent Eastern Europe viruses it has not been analyzed yet. Bebe This Russian virus contains the following pieces of text: VIRUS! Skagi "bebe" Fig Tebe ! A translation is not yet available. This is a 1004 byte virus, which only infects COM files. Best Wishes A 1024 byte .COM infecting virus, containing the text This programm ... With Best Wishes! The virus has not been analyzed yet, but many programs, including COMMAND.COM, will not work properly when infected. Black Monday The name of this virus is derived from a text string found inside it: Black Monday 2/3/90 KV KL MAL This is a 1055 byte virus, which will infect .EXE and .COM files. It is not possible to restore infected .EXE files, as the virus may overwrite some bytes at the end of the file. Blood A very simple 418 byte non-resident virus from Natal in South-Africa. It was written by a student, who claims to have no knowledge of how it "escaped". This virus, just like Kennedy, will only infect .COM files starting with a JMP statement (E9). Infected programs may occasionally display the following message when they are executed. File infected by BLOOD VIRUS version 1.20 Reports of a Blood-2 virus are based on a misunderstanding. Bulgarian Tiny This family of viruses currently contains the smallest viruses known - 198, 167, 160, 159, 158, 156, 154, 143, 138, 134 and 133 byte long. They do nothing of particular interest, but appear to be written in an attempt to write the smallest virus possible. Burger This virus was written by R. Burger, author of the Virdem virus. The virus is not a serious threat - a 560 byte destructive/overwriting virus, which is easily noticed as infected programs will not run normally. As with the 405 virus, disinfection is not possible. A few variants, slightly modified, possibly in order to bypass some scanning program are also known. Carioca This is a 951 byte .COM virus, which has not been analyzed yet. Cascade The Cascade virus, also known as 1701 or 1704, is probably one of the most common viruses around. The problem is just that it is often not detected, because it produces no obvious effects. In the original version, the virus contained code that was set to "go off" between Oct 1. and Dec 31. 1988, shortly after an infected program is run. The effect is actually quite amusing - the characters on the screen fall down and end in a heap on the bottom. There is a bug in some versions of the virus - it seems that the author intended the virus to infect all computers, except those from IBM. However, it did not work as planned - the virus would also infect "true" IBM machines. There is one variant of this virus, reported as 17Y4, which is almost identical to the most common 1704 variant. One byte has been changed, probably due to a random "mutation". This, however, has resulted in a "bug" in the virus. Another mutated variant is also known - it infects the same file over and over. Christmas in Japan This is a 600 byte virus from Japan, reported to activate on Dec. 25. It only infects .COM files, but has not been fully analyzed yet. DataCrime The DataCrime virus was probably written in W. Germany or the Netherlands. It caused much panic around Oct. 13th 1989 when it was set to go off. Any infected program run on Oct. 13 or later in the year would format the first nine tracks of the hard disk and display the message DATACRIME VIRUS RELEASED: 1 MARCH 1989 Since this virus is currently very rare, it is not a serious threat, but it could become a problem in the future. The two variants of this virus, 1280 and 1168 are practically equivalent, but another virus, called "DataCrime II" exists as well. It infects .EXE and .COM files, but the original "DataCrime" could only infect .COM files. DataCrime 2 is also a bit larger, 1514 bytes long and more complicated than the original virus. The latest variant, called DataCrime II-B is very similar to DataCrime II, but is only 1480 bytes long. Datalock A new, 920 byte virus, which has not been fully analyzed yet. It will infect .EXE files, but only some .COM files including COMMAND.COM. dBase The dBase virus is very rare, but rather curious. It is clearly intended to garble dBase files, or rather any file with a name that ends in .DBF. If the virus is active in memory when a program writes to a .DBF file, it will garble all the outgoing data. However, when the data is read back later, the virus will correct the garbled data. There is just one problem. If the virus is detected and removed, the data will be useless because the virus will not be present to "de-garble" it when it is read back. There is a more harmful side to this virus. If an attempt is made to write to a .DBF file that is more that three months old, the virus will try to destroy the FAT and root directory on drives D:, E: .... Z: There is a bug in the code, however, so the destruction will be rather unpredictable. The dBase virus will only infect .COM files, increasing their size by 1864 bytes. December 24th This virus was discovered in Iceland on Dec. 24th 1989. Several computers refused to run any programs at all on that date, but simply displayed the message "Gledileg jol" ("Merry Christmas") instead. The virus is a variant of the Icelandic-2 virus, but with several minor corrections and modifications. One out of every ten programs run is checked to see if it is a non-infected .EXE file. If so, the virus adds 848-863 bytes to the file. Destructor The name of this virus is derived from the following string which is stored inside it: DESTRUCTOR V4.00 (c) 1990 by ATA This is a 1150 byte wirus, which infects COM as well as EXE files. Devil's Dance A .COM infector reported to have originated in Spain or Mexico. It adds 951 bytes to the end of any file it infects. It will infect the same file over and over until it become too large to fit in memory. The virus traps INT 9 (the keyboard interrupt) and when CTRL-ALT-DEL is pressed it will display the message: DID YOU EVER DANCE WITH THE DEVIL IN THE WEAK MOONLIGHT ? PRAY FOR YOUR DISKS!! The Joker The virus also monitors any keystrokes, activating when 2000 are reached. It will then change the colors of any text displayed on the screen. When 5000 keystrokes are reached the virus will trash the first copy of the FAT. Diamond This is a 1024 byte virus from Bulgaria, which has been reported as bearing some resemblance to the "Eddie" virus, possibly written by the "Dark Avenger" as well. The virus makes some effort to disable any debugger program used to monitor it, but does not seem to do anything of particular interest. DIR This Bulgarian virus will infect files when the DIR command is given, hence the name. It is 691 bytes long, and will only infect .COM files. no destructive code has been found in the virus. Doteater A rather primitive 944 byte virus, probably written in Poland. It infects only .COM files, and when it activates it will remove all dots (.) from the screen. Durban (Saturday the 14th) This virus infects both .EXE and .COM files. It first adds 1-16 bytes to the files it infects length, so they end on a paragraph boundary. Then 669 additional bytes, containing the virus itself are written to the end. Durban is a resident virus, using a method similar to that used by Jerusalem to check if it already installed. On any Saturday the 14th, the first 100 logical sectors of drive C, then B, then A are overwritten with rubbish. Dyslexia Another name for this virus is "Solano", indicating its origin in Solano county in California. It is 2000 bytes long, adding 1991 bytes in front of .COM files, and 9 bytes at the end. The virus may prevent the proper execution of some programs, but does no serious damage. It is reported to transpose adjacent characters on the screen. The name is hidden in encrypted form inside the virus. Eddie This virus contains two interesting text strings: "Eddie lives...somewhere in time" and "This program was written in the city of Sofia (C) 1988-89 Dark Avenger" "Eddie" is probably the skeleton mascot of the heavy metal band "Iron Maiden". This was the first virus reported to have originated in Bulgaria, but it was soon followed by many other. There is only one thing unusual about this virus. It remains resident, just as many other viruses, but it will not only infect a program when it is run, but also when the program file is read. This means that a harmless program that opened each .EXE and .COM file in turn, for example to check them for infection, could easily cause an "epidemic". The virus will infect .EXE and .COM files, adding 1800 bytes to the length. COMMAND.COM will be one of the first programs to become infected. When an infected program is run, there is a 1-in-16 chance that the virus will trash a random disk sector. One 2000 byte variant is known. It is also from Bulgaria, probably written by the same author as the original one. It has been improved a bit - you won't see an increase in file length when you issue a DIR command. The third known variant, also by "Dark Avenger" is 2100 bytes long. Inside the virus one finds the following string Copy me - I want to travel or, in some versions Only the Good die young... The virus author also included the following string in the virus: Copyright (C) 1989 by Vesselin Bontchev Vesselin Bontchev, however, is a Bulgarian author of anti-virus programs, and has has nothing to do with the creation of the virus. The reason this message appears is that the virus searches for it in every program executed, and halts the computer when it is found. The author of the virus - Dark Avenger - has distributed the source and several new viruses can be expected in this family. One has appeared in the Soviet Union. It is known as "Hymn" and is 1865 bytes long. Eddie II A fairly harmless virus from Bulgaria - called "Eddie II" because it contains the string "Eddie lives". This string is similar to the string contained in the original "Eddie" virus. Eddie II can infect .EXE files as well as .COM files, but unlike most other .EXE infecting viruses, it does not pad them so their length becomes a multiple of 16 bytes, before they are infected. Infected files are marked with a value of 62 in the "seconds" field of the timestamp, which makes them immune to infection by Vienna or Zero Bug. Infected files grow by 651 bytes, but this increase will not be seen if a "DIR" command is given, because the virus intercepts the "find-first" and "find-next" functions, and if the "seconds" field contains 62, the virus will decrement the file length by 651. Apart from this the virus does nothing of interest. Fellowship The name of this virus is derived from the following text, which can be found inside it: This message is dedicated to all fellow PC users on Earth Towards A Better Tomorrow And A Better Place To Live In The virus is actually not very friendly - it attaches it to the end of .EXE files, but may overwrite the last 20 bytes or so of the original file. The virus itself is 1019 bytes long. It may cause further damage, but it has not yet been analyzed. Flash This virus probably originated in Germany. It adds 688 bytes to any .COM or .EXE file it infects. The virus is still awaiting full analysis. Flip The Flip virus is 2343 bytes long, and infects both .EXE and .COM files as well as boot sectors of hard disks. When the virus activates on a computer with an EGA or VGA display adapter, it will "flip" the screen horizontally and switch to a special character set, which reverses each character. This effect only happens on the second day of each month, between 16:00 and 16:59. The method used to infect boot sector is similar to that used by the V-1 virus, except the Flip virus will only infect hard disks, not diskettes. Frodo (4096, IDF) The Frodo virus infects both .EXE and .COM files. It is very advanced in some ways, being able to hide the infection by using a method similar to that used by the "Zero Bug" virus. If the virus is active in memory and you look at the directory, the virus will show you the original length of any infected program. The virus seems to be able to cause damage to data, as files may become crosslinked when it is active It activates on Sept. 22. when it may attempt to place a Trojan on boot sectors. This Trojan will display the message "FRODO LIVES" in large letters on the screen, surrounded by a moving pattern. The code to write the Trojan to the disk seems to be garbled in all known versions of the virus and will probably "hang" the computer. The length of infected files increases by 4096 bytes, but a variant "Fish 6", 3584 bytes long was recently reported. The effects of this variants are not known yet. Fu Manchu The author of the Fu Manchu virus seems to have intended to write one of the most humorous viruses around. He started with the Jerusalem virus, removed the harmful part of it and added several new features: The virus will censor the text the user types, deleting two four letter words. It will also take action if the user types "Thatcher", "Reagan", "Botha", or "Waldheim". In those cases it will add comments to the text. When Ctrl-Alt-Del is pressed, the virus will display the message The world will hear from me again! In other respects the virus is similar to the Jerusalem virus. It will infect both .EXE and .COM files, making them grow by about 2086 bytes. Fumble The "Fumble" virus is a small, memory resident .COM infecting virus that will generate typing errors, every now and then. That is, if you press the "R" key for example, it will occasionally insert another letter like "E" in the text instead. The only unusual feature of this virus is that it will only infect programs on odd-numbered days. Infected .COM files grow by 867 bytes. GhostBalls This virus was written in Iceland and first discovered there in October 1989. It contains the following text strings: GhostBalls, Product of Iceland Copyright (c) 1989, 4418 and 5F19 It will infect .COM files, making them grow in size by 2351 bytes. Basically it is just the Vienna virus - the variant in the book by Ralf Burger to be specific, with an extra twist. When an infected program is run, the virus will search for other programs to infect, but also try to place a modified copy of the Ping-Pong virus on the diskette in drive A, provided it is a 360K diskette. This Ping-Pong variant has been changed, so that it is not infectious, but it will also work on a '286 machine. This modified boot sector is not a virus, but F-DISINF will remove it. Guppy This is simple, 152 byte virus, which only infects .COM files, and may infect the same file over and over. Like the Kennedy virus, it will only infect files starting with a JMP. Hallöchen This is a .COM and .EXE infector, probably written in W-Germany. It contains two text strings: Hallöchen !!!!!!, Here I'm.. Acrivate Level 1.. This virus is a bit unusual in some ways - for example it will not infect "old" files. If the value of the "month" or "year" fields in the timestamp is different from the current date, the file will not be infected. The virus does not modify the creation date when it infects the virus, and like most other viruses it is easily able to defeat the read-only attribute. It will only infect files larger than 5000 bytes, increasing their length by 2011 bytes. The major effect is reported to be garbling of keyboard input. Icelandic This virus was first found in Iceland in June '89. If only infects files with names ending in .EXE. When an infected program is run, it will hide in memory by directly manipulating the Memory Control Blocks. Programs that watch out for any program "going TSR" will therefore not be able to catch it. This virus will mark one cluster on the hard disk as bad, every time it infects a file. A minor variant of this virus was later found in Saratoga, and a radically modified version appeared in Iceland in July '89. This new version (Icelandic-2) does not use INT 21 calls like the original, but instead makes direct JMPs into the operating systems. This means that many protection programs will be unable to catch it. Icelandic-1 is 656 bytes long, Saratoga is 642 bytes but Icelandic-2 adds 632 bytes to any file it infects. Actually the file may grow a bit more because all the viruses will first pad the file so the length becomes a multiple of 16 bytes. Internal A 1381 byte .EXE-infecting virus, which may occasionally garble the screen and display a fake error message. Itavir This is a fairly long, 3880 byte, Italian EXE file infector. The virus is reported to activate after the system has been left running for at least 24 hours It will then corrupt the boot sector, write out a message in Italian, and start writing random values to all I/O ports. This is reported to cause a "hissing" sound from some VGA monitors.