Date: Mon, 13 Sep 1999 17:35:32 -0400 From: "Donald J . Maddox" <dmaddox@conterra.com> To: The Mad Scientist <madscientist@thegrid.net> Cc: freebsd-security@FreeBSD.ORG Subject: Re: How to prevent motd including os info Message-ID: <19990913173532.A842@dmaddox.conterra.com> In-Reply-To: <4.1.19990913003757.0096b660@mail.thegrid.net> References: <4.1.19990913003757.0096b660@mail.thegrid.net>
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Bzzzt! The correct answer is in /etc/login.conf, of course. You assume a lot. How do you know I don't have the user in a jail that doesn't even remotely resemble a *BSD system (even though it actually is within one)? On Mon, Sep 13, 1999 at 12:38:35AM -0700, The Mad Scientist wrote: > If someone can get a shell on your machine, it should be trivial to > determine (at the very least) that the machine is running a bsd OS. > (existance of /usr/ucb, flags to ps, etc) You'd need to take care of > uname, dmesg, and so on. It's better to spend your time fixing real > security holes. > -Dean > At 01:13 PM 9/12/99 -0400, you wrote: > >Is there a way to suppress the copyright info? This is pretty much > >a dead giveaway (At least that it's *BSD), huh? See lines 14-15 below: > > > >$ telnet dmaddox.conterra.com > >Trying 127.0.0.1... > >Connected to localhost. > >Escape character is '^]'. > > > >dmaddox.conterra.com > >Access Restricted > > > >Today is Sun Sep 12 13:09:57 EDT 1999 > > > >login: myself > >Password: > >Last login: Sun Sep 12 13:07:17 from localhost > >Copyright (c) 1980, 1983, 1986, 1988, 1990, 1991, 1993, 1994 > > The Regents of the University of California. All rights reserved. > > > >Welcome to BogoDOS! > >You have mail. > >$ > > > > > >On Sun, Sep 12, 1999 at 12:56:39PM -0400, Hector Colmenares wrote: > >> > >> > >> If you dont want people to know what OS are you running > >> when they telnet into your box just change to this the info in > >> /etc/gettytab > >> > >> default:\ > >> :cb:ce:ck:lc:fd#1000:im=\r\n\%h\r\nAccess Restricted\ > >> r\n\r\nFor info, email admin@%h\r\nToday is %d\r\n\r\n > >> > >> > >> ;-) > >> > >> cheers !! > >> > >> On Sun, 12 Sep 1999, Will Andrews wrote: > >> > >> > > >> > On 12-Sep-99 Ben Smithurst wrote: > >> > > Jeremy L. Ramirez wrote: > >> > > > >> > >> telnet stream tcp nowait root /usr/libexec/telnetd > >telnetd -h > >> > >> > >> > >> what you are doing is adding the -h at the end of the line which > >prevents > >> > >> a user from seeing the OS before even logging in. > >> > > > >> > > An even better way is to disable telnet completely, and use ssh like > you > >> > > should. Note that people can still use nmap or something to guess at > >> > > your OS. > >> > > > >> > > -- > >> > > Ben Smithurst | PGP: 0x99392F7D > >> > > ben@scientia.demon.co.uk | key available from keyservers and > >> > > | ben+pgp@scientia.demon.co.uk > >> > > > >> > > > >> > > To Unsubscribe: send mail to majordomo@FreeBSD.org > >> > > with "unsubscribe freebsd-security" in the body of the message > >> > > >> > > >> > To Unsubscribe: send mail to majordomo@FreeBSD.org > >> > with "unsubscribe freebsd-questions" in the body of the message > >> > > >> > >> > >> > >> To Unsubscribe: send mail to majordomo@FreeBSD.org > >> with "unsubscribe freebsd-questions" in the body of the message > >> > > > > > >To Unsubscribe: send mail to majordomo@FreeBSD.org > >with "unsubscribe freebsd-security" in the body of the message > > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-security" in the body of the message > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-security" in the body of the message
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