[Iftop-users] Security Issue With iftop

[Paul Warren]

Ali,

On 18 Jan 2010, at 16:35, Ali Jawad wrote:

> As you all know a non root user can not run iftop. So the most  
> obvious workaround is to use sudo. Now if you give a regular user  
> sudo access he will execute.
>
> sudo iftop
>
> Once he is inside iftop. He can execute ! he will get the following  
> promtp
>
> command >

I have to say, I'd completely forgotten that that feature existed!

> At this point a user can execute su, and he will get a root shell.  
> He can also execute any command in privileged mode. The idea of  
> using sudo initially was giving the user iftop access. However the  
> user ends up with total root access.

Indeed.

There are two answers to this.  The first is that although this  
provides the user with a very direct and simple way of getting a  
shell, I would not warrant that there are not bugs in either iftop or  
any of it's library dependencies that can be exploited to give  
privilege escalation.  This applies to just about any non-trivial  
program that you may wish to make available via sudo.

The second answer is that there's a compile-time option to disable  
this functionality (which I'd also forgotten about, but the change log  
claims it was introduced in 0.17).

I can't remember exactly how to use it, but something like:

	export CFLAGS=-DNO_SYSTEM

then rebuilding may do what you want.

Paul