On Monday 16 December 2002 16:24 pm, Clayton Cornell wrote:
A friend and I are having a rather long email discussion about security in Linux. He has raised some questions I don't know the answer to... maybe someone here on the list can help out.
The discussion is centering around what happens if you are using Linux and someone sends you a malicious binary. If you save it to your /home/<user> and run it, not knowing it is something nasty, what can it do to your system? If you are running as <user> the worst I can imagine it could do is turf your files in /home/<user>. Is this possible assuming a compiled binary?
If you are a TOTAL RAVING LOON ENOUGH TO RUN A BINARY just anyone sends you, then it could very easily do almost anything to your system including erase all the files or even clobber all your partitions. Point is: don't run things like that, and if you really, really want to, still don't do it... but then if someone points a gun to your head, run it as a simple user where the permissions should prevent it from doing much damage.
If you can run application XYZ as <user> what is to stop that binary from running application XYZ as well (after you ran the binary and it is hovering in the background)? Can a program pretend to be <user> and execute applications as <user>? I am not talking about a simple text shell script that you can read... I am talking about a binary you cannot look at/into or see the source code.... essentially a Linux virus scenario.
C.
If you're going to run binaries, anything is possible. The main thing about Linux is that it doesn't tend to run anything without someone actually giving a command to run it... as opposed to Winders, where things get run automatically by Outlook Express, or Exel, or any of the other goodies that Billy did so well at writing.... Macros, etc.. that are also hidden. -- +----------------------------------------------------------------------------+ + Bruce S. Marshall bmarsh@bmarsh.com Bellaire, MI 12/16/02 17:16 + +----------------------------------------------------------------------------+ "Those of you who think you know everything are annoying those of us who do."