Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1a 7/7/83; site rlgvax.UUCP Path: utzoo!linus!philabs!seismo!rlgvax!guy From: guy@rlgvax.UUCP Newsgroups: net.unix-wizards Subject: Re: Security and $PATH Message-ID: <939@rlgvax.UUCP> Date: Mon, 1-Aug-83 04:28:27 EDT Article-I.D.: rlgvax.939 Posted: Mon Aug 1 04:28:27 1983 Date-Received: Mon, 1-Aug-83 22:46:36 EDT References: <396@houxq.UUCP> Organization: CCI Office Systems Group, Reston, VA Lines: 32 On the UNIX systems I am familiar with (running USG 5.0), the PATH variable is set, both in /etc/profile and in login, to begin with a ':', meaning that the current directory is the first directory to be searched. It seems to me that this is a significant security hole, because it means that a user can set a booby trap by writing a shell that has the same name as a common command, but does something significantly different. Is it a common practice to have the default PATH begin with a ':'? Is there a real good reason to make this the default? Yes, it is an almost universal practice. However, all USG systems I know about DO protect the superuser; the default PATH for "root" is /bin:/etc:/usr/bin (or some permutation thereof). I find it a pain when "root" to have to say "./xxx" to run a test version of the program "xxx" (for obscure reasons I do most development work on our System III systems as "root"), but I have gotten into the habit of saying "./xxx". There is a good reason to make it the default; people are used to it. If somebody feels like being very security-conscious I feel it is THEIR responsibility to change their PATH. I suspect it's somewhat of an issue like compulsory seat-belt laws or helmet laws; some feel it is a person's responsibility to protect themselves and some feel this protection should be required whether the person wants it or not. (No flames please, this is NOT a statement of my views on seat-belt or helmet laws.) As such, I guess it's really up to the system administrator; you can always hack "/etc/profile", and anybody who doesn't like the PATH they've been given can always replace it in their ".profile" anyway. Guy Harris {seismo,mcnc,we13,brl-bmd,allegra}!rlgvax!guy