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The difference between viruses then (most did little real harm, left your computer in perfectly working state, and were meant to show off the skills of the writ

by danjayh 13y ago

The difference between viruses then (most did little real harm, left your computer in perfectly working state, and were meant to show off the skills of the writer) and now (network zombies used to make people money, or replace web content with ads) is kind of depressing.

ComputerGuru 13y ago
To be honest, back then most computers didn't have a direct connection to the online world.. and even if they did, it was rarely always-on. But it's not all sunshine and roses, do you remember the scourge of toll-dialer viruses (that made your dial-up modem call a toll number that bills by the minute, money going to the attacker) from back in the day? There were a rare few that could even figure out ways to silence your dial-up tone so you wouldn't be guaranteed to instantly find out you'd been infected..
- caf 13y ago
  That was just an AT command: ATM0
  - ComputerGuru 13y ago
    That's assuming DOS had the right drivers for your card loaded, and that your card respected that option... I came across many that didn't, esp. the "cheap" knockoffs of the leading brands.
    - ksk 13y ago
      Drivers? Do you mean software-modems? Majority of the modems AFAIK were hardware modems which just connect over the COM ports, and you can echo any command there.
johnchristopher 13y ago
> most did little real harm, left your computer in perfectly working state, and were meant to show off the skills of the writer Maybe on UNIX or something but viruses I remember from the early 90's were zeroing HDD, replacing files with the same text or rebooting every 5 minutes. I'd venture to say that except for ransomware today's viruses and trojans are more discrete and do less harm to the user because if the user notices them he's going to take action to remove them and that weakens the botnet or the ad delivery collective system which seem to be what viruses and trojan writers really want to have.
- ksk 13y ago
  >I'd venture to say that except for ransomware today's viruses and trojans are more discrete and do less harm to the user because if the user notices them he's going to take action to remove them and that weakens the botnet or the ad delivery collective system which seem to be what viruses and trojan writers really want to have. You're right, that certainly is the goal, but IME almost never achieved. I've cleaned up quite a few infections and almost all of them have caused some kind of system instability or another. Virus writers have surprisingly shoddy programming skills.
ksk 13y ago
>and were meant to show off the skills of the writer I believe that is just nostalgia. I have reverse engineered a few and almost all of them are badly designed, make assumptions about the state of the OS/datastructures (that turn out to be false sometimes, causing them to crash) and do things that are trivial for any intermediate low-level programmer. Commonly - modify command.com or other executables to load itself when executed (some tricky viruses even removed their modifications from those EXEs once they were memory resident) , plop some executable code in the bootsector, hook into some i/o interrupt, install itself as a TSR, etc Modern malware is equally buggy, but will do things that are much much more sophisticated - due to the arms race between antivirus folks and malware writers. Especially the techniques they use to thwart being live-debugged, or identified as malware are pretty ingenious. A lot of DRM tech. (securom comes to mind) does similar crazy stuff as well - in addition to causing system instability.

by danjayh 13y ago

ComputerGuru 13y ago

To be honest, back then most computers didn't have a direct connection to the online world.. and even if they did, it was rarely always-on. But it's not all sunshine and roses, do you remember the scourge of toll-dialer viruses (that made your dial-up modem call a toll number that bills by the minute, money going to the attacker) from back in the day? There were a rare few that could even figure out ways to silence your dial-up tone so you wouldn't be guaranteed to instantly find out you'd been infected..

caf 13y ago
That was just an AT command: ATM0
- ComputerGuru 13y ago
  That's assuming DOS had the right drivers for your card loaded, and that your card respected that option... I came across many that didn't, esp. the "cheap" knockoffs of the leading brands.
  - ksk 13y ago
    Drivers? Do you mean software-modems? Majority of the modems AFAIK were hardware modems which just connect over the COM ports, and you can echo any command there.

johnchristopher 13y ago

> most did little real harm, left your computer in perfectly working state, and were meant to show off the skills of the writer Maybe on UNIX or something but viruses I remember from the early 90's were zeroing HDD, replacing files with the same text or rebooting every 5 minutes. I'd venture to say that except for ransomware today's viruses and trojans are more discrete and do less harm to the user because if the user notices them he's going to take action to remove them and that weakens the botnet or the ad delivery collective system which seem to be what viruses and trojan writers really want to have.

ksk 13y ago
>I'd venture to say that except for ransomware today's viruses and trojans are more discrete and do less harm to the user because if the user notices them he's going to take action to remove them and that weakens the botnet or the ad delivery collective system which seem to be what viruses and trojan writers really want to have. You're right, that certainly is the goal, but IME almost never achieved. I've cleaned up quite a few infections and almost all of them have caused some kind of system instability or another. Virus writers have surprisingly shoddy programming skills.

ksk 13y ago

>and were meant to show off the skills of the writer I believe that is just nostalgia. I have reverse engineered a few and almost all of them are badly designed, make assumptions about the state of the OS/datastructures (that turn out to be false sometimes, causing them to crash) and do things that are trivial for any intermediate low-level programmer. Commonly - modify command.com or other executables to load itself when executed (some tricky viruses even removed their modifications from those EXEs once they were memory resident) , plop some executable code in the bootsector, hook into some i/o interrupt, install itself as a TSR, etc Modern malware is equally buggy, but will do things that are much much more sophisticated - due to the arms race between antivirus folks and malware writers. Especially the techniques they use to thwart being live-debugged, or identified as malware are pretty ingenious. A lot of DRM tech. (securom comes to mind) does similar crazy stuff as well - in addition to causing system instability.