Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!swrinde!cs.utexas.edu!uunet!mcsun!unido!nixpbe!nixsin!koerber.sin@sni.de From: koerber.sin@sni.de (Mathias Koerber) Newsgroups: comp.unix.admin Subject: Re: Mysterious security hole Message-ID: <2011@nixsin.UUCP> Date: 27 Jun 91 02:32:59 GMT References: <1991Jun21.203054.989@serval.net.wsu.edu> <1991Jun22.220635.17145@rock.concert.net> <2007@nixsin.UUCP> <1991Jun26.080351.21035@ukpoit.co.uk> Sender: koerberm@nixsin.UUCP Reply-To: koerber.sin@sni.de Organization: Siemens Nixdorf Information Systems (Singapore) Pte Ltd Lines: 52 In article <1991Jun26.080351.21035@ukpoit.co.uk> alan@ukpoit.co.uk (Alan Barclay) writes: |In article <2007@nixsin.UUCP> koerber.sin@sni.de writes: |>[ after the PATH=:/bin:/usr/bin security dicussion was going on for quite |> some time, deleted... ] |>No, but if '.' is in your path, and you are in /tmp, that will do some damage. |>Same thing for any writable dir in your path. Maybe UNIX should have an |>option which lets one refuse to run |> a) writable scripts/programs |> b) setuid scripts/programs | |Ah, so you don't want to run ps, mail or at, to name three programs which |are normally setuid. Also when root a lot of programs have permissions |of 7xx so almost all programs would be writable. First an addition: c) programs not owned by user Not necessarily, but as superuser I'd be greatful to an option (ENVIRONMENT- VARIABLE or so), which would make exec/sh/etc refuse to run those programs. Simply because I might mistype. Imagine: # PARANOID=4 export PARANOID ^--some kind of level here, or bitmode or ... # echo $PARANOID 4 # la -l <---- obviously a type PARANOID: /tmp/la is setuid # mail PARANOID: /bin/mail is writable # vo /etc/passwd <--- another typo PARANOID: /usr/local/bin/vo is not ownded by root # PARANOID=0 vo /etc/passwd ^--- I really want to run this.. or even # PARANOID=99 export PARANOID # la -l PARANOID: executing /u0/local/bin/la (y/n):n PARANOID: execution denied You don't have to use this all the time, but if you know you are going to do something tricky, or u suspect pitfalls, the extra help might be welcome. Mathias Koerber | S iemens | EUnet: koerber.sin@sni.de 2 Kallang Sector | N ixdorf | USA: koerber.sin@sni-usa.com S'pore 1344 | I nformation Systems | Tel: +65/7402852 | Fax: +65/7402834 I can resist everything but TEMPTATION |#include