Date: Tue, 13 Jul 1999 04:06:41 -0400 (EDT) From: Robert Watson <robert@cyrus.watson.org> To: Doug Rabson <dfr@nlsystems.com> Cc: Mark Newton <newton@atdot.dotat.org>, Mike Tancsa <mike@sentex.net>, security@freebsd.org, stable@freebsd.org Subject: Re: 3.x backdoor rootshell security hole Message-ID: <Pine.BSF.3.96.990713040415.14330C-100000@fledge.watson.org> In-Reply-To: <Pine.BSF.4.10.9907122031140.58023-100000@salmon.nlsystems.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On Mon, 12 Jul 1999, Doug Rabson wrote: > On Mon, 12 Jul 1999, Robert Watson wrote: > ... > > In fact, if you have permission to modify the running kernel, you may have > > more privilege than that of a root process, with securelevels.. :-) What > > the THC posting is really about it hiding compromises on a machine that > > has been compromised, and leaving backdoors. The title, "Attacking > > FreeBSD..." is a little misleading, it's more about "Trojaning FreeBSD > > Once You Already Have Absolute Control of a Machine". And these aren't > > even very persistent: they have to be reloaded after each boot, meaning > > changes to configuration files, etc, etc. > > Also if a site is running using securelevel, even root can't load files > into the running kernel. The attacker would have to arrange to load the > code during startup and reboot the box (a noticable event surely). > > Hmm. Shouldn't we protect the contents of /boot with the schg flag? Ideally some of the directories themselves, as well as /boot, parts of /etc large parts of /sbin and /bin (including sh, as that gets run in single-user mode)... My feeling is we should maintain a list, but not ship that way as it would be irritating for most of the world. At one point I had a script that did some of the work, but currently due to file layout and the way we do config files, you end up with a fairly hobbled machine. Which is, of course, the idea. :-) I think security(8) (?) discusses a fair amount of this stuff. Robert N M Watson robert@fledge.watson.org http://www.watson.org/~robert/ PGP key fingerprint: AF B5 5F FF A6 4A 79 37 ED 5F 55 E9 58 04 6A B1 TIS Labs at Network Associates, Computing Laboratory at Cambridge University Safeport Network Services To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?Pine.BSF.3.96.990713040415.14330C-100000>