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From: lenny@quincy.UUCP (Lenny Tropiano)
Newsgroups: comp.sys.att,comp.unix.wizards
Subject: UNIX PC Security (errata and such)
Message-ID: <64@quincy.UUCP>
Date: Fri, 9-Oct-87 08:32:15 EDT
Article-I.D.: quincy.64
Posted: Fri Oct  9 08:32:15 1987
Date-Received: Mon, 12-Oct-87 04:24:41 EDT
Organization: American LP Systems, Inc., Islandia, NY
Lines: 47
Keywords: security, unix-pc, network, bug
Xref: mnetor comp.sys.att:1447 comp.unix.wizards:4809

Errata from last article:

In my last article where I stated that /etc/lddrv/lddrv should be
protected as 4750, instead of 4755, so not everyone can "allocate
and deallocate system drivers..."  Well I found out that "ipcs" uses
this to see if the ipc (interprocess communication) driver is loaded.
ipcs runs as setgid sys... you have two alternatives if you want the
load-driver (lddrv) program protected:

	chown root /usr/bin/ipcs 
	chmod 6755 /usr/bin/ipcs  (setuid root, setgid sys)

		-or-

	chgrp sys /etc/lddrv/lddrv (probably more preferred)


Someone else pointed out that my "find" statement would take a long
time to run, since it exec'd "/bin/ls" for each file.  A more refined
find command would be...

find / -perm -4000 -print | xargs ls -ld | more

The permission mask 4000 can be changed to check any bit that you
like.  Thanks to the people who mentioned this.

---------------------------------------------------------------------

A new possible problem is the protection of files at 777.
Here are some of them:

-rwxrwxrwx  1 root    bin           0 Sep  6 23:58 /etc/.fontload
-rwxrwxrwx  1 bin     bin          14 Jan  1  1970 /etc/.modem
-rwxrwxrwx  1 bin     bin          64 Sep 20 17:28 /etc/.rs232
-rwxrwxrwx  1 root    users     24101 Sep 27 09:38 /etc/lddrv/ate
-rwxrwxrwx  1 root    root      26784 Sep 27 09:38 /etc/lddrv/kbd
-rwxrwxrwx  1 root    root      34109 Sep 10 20:07 /etc/lddrv/lipc
-rwxrwxrwx  1 root    root      56982 Sep 10 23:01 /etc/lddrv/wind
drwxrwxrwx  6 bin     bin        1376 Oct  3 13:31 /usr/lib/ua

Those drivers shouldn't be 777, 755 will do.

-- 
Lenny Tropiano                      ...seismo!uunet!godfre!quincy!lenny  -or-
American LP Systems, Inc.           ...cmcl2!phri!gor!helm!quincy!lenny  -or-
1777-18 Veterans Memorial Hwy.   	          ...mtune!quincy!lenny  -or
Islandia, New York 11722     +1 516-582-5525 ...ihnp4!icus!quincy!lenny