Linux Security: Disabling misc tools
The most common modus operandi for the bulk of the system
crackers out there is to gain access to your system, often
through a regular user account, and then use that access to
compile exploits against your system or other systems, or use
your network tools for DoS attacks against other systems.
Disabling the compiler on your system will slow these crackers
down,and may even prevent some attacks entirely.
Note: This only covers basic compiling/system/network tools
First we'll start with compiling tools. A cracker can always
upload his/her own compilers to compile exploits to gain
root access to your box, but by disabling these tools. We slow
the cracker down and also show not only crackers but other users
on the box that you mean business when it comes to system
security.
If you wish to disable compiling tools to everyone but root do
these chmod's
(also please see the chmod manual page)
chmod 0700 /usr/bin/gcc
chmod 0700 /usr/bin/g++
chmod 0700 /usr/bin/cc
chmod 0700 /usr/bin/colorgcc
Next system tools and network tools:
These system tools can be used to gain knowledge about other
users on the system
by disabling these we can slow down or possibly prevent a cracker
from gaining
such knowledge
If you wish to disable these system tools do these chmods, and
also see the man pages for the ones that you don't know what they
do.
chmod 0700 /usr/bin/w
chmod 0700 /usr/bin/who
chmod 0700 /usr/bin/finger
Now the network tools:
Only you the system admin of your box should have access to the
network tools of the system, hence I would recommend disabling
these tools to everyone except root. To do so, do these
chmods...
chmod 0700 /bin/ping
chmod 0700 /usr/bin/telnet (or possibly /bin/telnet)
chmod 0700 /usr/bin/ssh (if you have ssh installed)
chmod 0700 /usr/sbin/traceroute
Please dig deeper into this subject!
And please see manual page for chmod!