4 ms·

A dive into the world of MS-DOS viruses

100 points by fcambus 8y ago

anonymouzz 8y ago
Any chance someone could upload the VX Heavens dataset of viruses to the Internet Archive? https://archive.org/details/malwaremuseum https://archive.org/details/malwaremuseum
- deleted 8y ago
  [deleted]
- EvanAnderson 8y ago
  They're there already: https://archive.org/search.php?query=subject%3A%22vx+heaven%22 https://archive.org/search.php?query=subject%3A%22vx+heaven%...
EvanAnderson 8y ago
Discussion about the 35C3 talk from a few days ago: https://news.ycombinator.com/item?id=18790889 https://news.ycombinator.com/item?id=18790889
dzhiurgis 8y ago
Wondering whats the latest activation date found in entire archive. He mentioned he sampled all dates up to 2005.
kazinator 8y ago
Guilty. In 1988 or so I made a virus that attached to .com files, which would spread it to others when executed. It was never released into the open. On each infection, it incremented a generation counter. Upon reaching a certain value, the payload would trigger, causing a message to be printed. What the heck was I using? MASM? TASM? I cannot remember. IIRC, looking for other .com files was just using DOS's FindFirst and FindNext functions at int 21h. (I'm now naming them in terms of their Win32 counterparts.) I think I didn't have a sanity check against duplicate infection in the early versions and added that during testing. 17 year old's programmer's "doh" moment. I remember that I ran the experiments in a subdirectory called "petridir". :)
LaserDiscMan 8y ago
I always thought the Casino DOS virus was pretty inventive. If an infected file is run on the payload date, it moves the FAT to RAM and warns the user not to shut down their computer. The user plays a game with IIRC a 1/17 chance of winning. If they win, the FAT is restored, else it's gone. I think it's an interesting way of holding the PC hostage. A video of the virus in action: https://www.youtube.com/watch?v=wdZJHvBRRqg https://www.youtube.com/watch?v=wdZJHvBRRqg, that channel has loads of videos documenting DOS/Win9X viruses. Some are very creative.
- mistaken 8y ago
  Actually it doesn't restore FAT even if you win :) Check out: https://imgur.com/a/jru1vRn https://imgur.com/a/jru1vRn
alyandon 8y ago
Ah yes, I have fond memories of writing TSR pranks that hooked common DOS interrupts (not technically viruses since they didn't infect/replicate) that did things like: 1) buffer 1 keystroke in memory (so typing diw<backspace>r would leave "di" on screen - then they'd type "r" and get an "r" and then hit enter and get another "r", then they'd hit backspace to correct the "dirr" and the command would execute, etc) 2) hooked the printer interrupt to introduce typos in printouts 3) randomly swap letters on the screen periodically Fun times. It's probably for the best that I grew up in the era that I did since pulling pranks like these has a high risk of getting slapped with felony charges in this day and age.
- kazinator 8y ago
  I played a prank of this type in some Unix C code that was homework for some third or fourth year networking or operating systems class. The executable forked off a prank process which simulated the effect of the professor doing a write to the teaching assistant's TTY. The fake professor's console message claimed that he happens to be looking at the same homework, which looks quite good and deserves a solid 19/20. And so when I got this back, the mark was 19/20 with a note saying "Well, <profname> told me to". Haha!
- gesman 8y ago
  When I was young I build small TSR .com (DOS exec extension) thing to instantly switch screen from game playing mode to serious work-BS mode with hotkey - at a first sign of boss approaching.
  - gattilorenz 8y ago
    Ah, the good old "boss key" present in so many games! I remember it from Leisure Suit Larry [1], and a few more. At the time it was more like a "mom key" :) The open office was probably invented as a countermeasure for the boss key. [1] https://www.mobygames.com/game/leisure-suit-larry-goes-looking-for-love-in-several-wrong-places/screenshots/gameShotId,57500/ https://www.mobygames.com/game/leisure-suit-larry-goes-looki...
- heyjudy 8y ago
gordaco 8y ago
From the perspective of the user, MS-DOS was a lousy OS. However, as a tinkerer, it was super fun. To this day, my best programming memories are about using Turbo Assembler and the information from Interrup.lst to do weird things with the graphics card's text mode (unusual resolutions, borders, 18 bit color palettes, smooth scrolling...). EDIT: typo.
unixhero 8y ago
Some WERE malicious. Such as the virus "FORM", which corrupted the partition somehow.

100 points by fcambus 8y ago

Any chance someone could upload the VX Heavens dataset of viruses to the Internet Archive? https://archive.org/details/malwaremuseum https://archive.org/details/malwaremuseum

deleted 8y ago
[deleted]
EvanAnderson 8y ago
They're there already: https://archive.org/search.php?query=subject%3A%22vx+heaven%22 https://archive.org/search.php?query=subject%3A%22vx+heaven%...

EvanAnderson 8y ago

Discussion about the 35C3 talk from a few days ago: https://news.ycombinator.com/item?id=18790889 https://news.ycombinator.com/item?id=18790889

dzhiurgis 8y ago

Wondering whats the latest activation date found in entire archive. He mentioned he sampled all dates up to 2005.

kazinator 8y ago

Guilty. In 1988 or so I made a virus that attached to .com files, which would spread it to others when executed. It was never released into the open. On each infection, it incremented a generation counter. Upon reaching a certain value, the payload would trigger, causing a message to be printed. What the heck was I using? MASM? TASM? I cannot remember. IIRC, looking for other .com files was just using DOS's FindFirst and FindNext functions at int 21h. (I'm now naming them in terms of their Win32 counterparts.) I think I didn't have a sanity check against duplicate infection in the early versions and added that during testing. 17 year old's programmer's "doh" moment. I remember that I ran the experiments in a subdirectory called "petridir". :)

LaserDiscMan 8y ago

I always thought the Casino DOS virus was pretty inventive. If an infected file is run on the payload date, it moves the FAT to RAM and warns the user not to shut down their computer. The user plays a game with IIRC a 1/17 chance of winning. If they win, the FAT is restored, else it's gone. I think it's an interesting way of holding the PC hostage. A video of the virus in action: https://www.youtube.com/watch?v=wdZJHvBRRqg https://www.youtube.com/watch?v=wdZJHvBRRqg, that channel has loads of videos documenting DOS/Win9X viruses. Some are very creative.

mistaken 8y ago
Actually it doesn't restore FAT even if you win :) Check out: https://imgur.com/a/jru1vRn https://imgur.com/a/jru1vRn

alyandon 8y ago

Ah yes, I have fond memories of writing TSR pranks that hooked common DOS interrupts (not technically viruses since they didn't infect/replicate) that did things like: 1) buffer 1 keystroke in memory (so typing diw<backspace>r would leave "di" on screen - then they'd type "r" and get an "r" and then hit enter and get another "r", then they'd hit backspace to correct the "dirr" and the command would execute, etc) 2) hooked the printer interrupt to introduce typos in printouts 3) randomly swap letters on the screen periodically Fun times. It's probably for the best that I grew up in the era that I did since pulling pranks like these has a high risk of getting slapped with felony charges in this day and age.

kazinator 8y ago
I played a prank of this type in some Unix C code that was homework for some third or fourth year networking or operating systems class. The executable forked off a prank process which simulated the effect of the professor doing a write to the teaching assistant's TTY. The fake professor's console message claimed that he happens to be looking at the same homework, which looks quite good and deserves a solid 19/20. And so when I got this back, the mark was 19/20 with a note saying "Well, <profname> told me to". Haha!
gesman 8y ago
When I was young I build small TSR .com (DOS exec extension) thing to instantly switch screen from game playing mode to serious work-BS mode with hotkey - at a first sign of boss approaching.
- gattilorenz 8y ago
  Ah, the good old "boss key" present in so many games! I remember it from Leisure Suit Larry [1], and a few more. At the time it was more like a "mom key" :) The open office was probably invented as a countermeasure for the boss key. [1] https://www.mobygames.com/game/leisure-suit-larry-goes-looking-for-love-in-several-wrong-places/screenshots/gameShotId,57500/ https://www.mobygames.com/game/leisure-suit-larry-goes-looki...
heyjudy 8y ago

gordaco 8y ago

From the perspective of the user, MS-DOS was a lousy OS. However, as a tinkerer, it was super fun. To this day, my best programming memories are about using Turbo Assembler and the information from Interrup.lst to do weird things with the graphics card's text mode (unusual resolutions, borders, 18 bit color palettes, smooth scrolling...). EDIT: typo.

unixhero 8y ago

Some WERE malicious. Such as the virus "FORM", which corrupted the partition somehow.