[comp.unix.admin] Protecting against downloads

sralston@srwic.UUCP (Steve Ralston) (09/14/90)

In article <3952@quiche.cs.mcgill.ca>
   mikey@quiche.cs.mcgill.ca (Michael GALLOP) writes:

>Exactly, what you can do is:
>chmod 711 /usr/bin/* 
>Which produces (I think :-)) rwx--x--x on every file in /usr/bin

I would NOT recommend that anyone execute the above command on their **IX
system.  Reason:  You will break most every program that relies on SETUID
and/or SETGID permissions.  Unless you KNOW (or have recorded) the default
permissions [anywhere on your system], running that kind of chmod command
could cost you much effort to undo.

Much better would be:

chmod o-r /usr/bin/*		# revoke read permission from "others"
				# (other than user (owner) or group)

but then, hardly any of the programs in /usr/bin should have "other read"
perms set by DEFAULT anyway; unless you're running a fairly non-secure
system.
-- 
Steve Ralston						sralston@srwic.UUCP
235 N Zelta						voice: 316-686-2019
Wichita, KS 67206			..!uunet!ncrlnk!ncrwic!srwic!sralston

cpcahil@virtech.uucp (Conor P. Cahill) (09/15/90)

In article <188@srwic.UUCP> sralston@srwic.UUCP (Steve Ralston) writes:
>chmod o-r /usr/bin/*		# revoke read permission from "others"
>				# (other than user (owner) or group)
>
>but then, hardly any of the programs in /usr/bin should have "other read"
>perms set by DEFAULT anyway; unless you're running a fairly non-secure
>system.

Or, of course, unless the program is a shell script which would then 
no longer work.


-- 
Conor P. Cahill            (703)430-9247        Virtual Technologies, Inc.,
uunet!virtech!cpcahil                           46030 Manekin Plaza, Suite 160
                                                Sterling, VA 22170