On Tue, Feb 29, 2000 at 09:23:32PM -0500, Shourya Sarcar wrote:
> The magic (read obvious sensibility) about *NIX is that it does not give
> you perms/priviledges to write whaatever you want, wherever you want.
>
A *proper* virus under Linux would need to execute as root, could load a module
(through a variety of methods) and intercept system-calls such as sys_open,
sys_execve etc. You can compare this with a DOS virus rerouting an INT 21H or
INT 13H, INT 8 Interrupt Service Routine (ISR) to itself. Running at kernel-
level gives you privileges on par with those available to viruses under
DOS.
The advantage of most Unixen is that a normal user has to overcome filesystem
and memory protections (separate UIDs, non-root permissions) before being
in a position to take-over a system-call.
The word "virus" under Linux brings to my mind a program known as an "LDT
infector". I forgot whether this *was* a virus.
--vml,
Model Engg. College, Cochin
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