*BSD News Article 48569


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From: bs@Germany.EU.net (Bernard Steiner)
Newsgroups: comp.unix.bsd.misc,comp.unix.bsd.bsdi.misc
Subject: Re: Circumventing immutable file protections
Date: 9 Aug 1995 10:08:47 +0200
Organization: EUnet Deutschland GmbH, Dortmund, Germany
Lines: 21
Message-ID: <409qef$t3n@Germany.EU.net>
References: <DCvE8s.15A@candle.pha.pa.us> <4095br$3tj@kragar.kei.com>
NNTP-Posting-Host: qwerty.germany.eu.net
Xref: euryale.cc.adfa.oz.au comp.unix.bsd.misc:158 comp.unix.bsd.bsdi.misc:583


In article <4095br$3tj@kragar.kei.com>, ckd@loiosh.kei.com (Christopher Davis) writes:
|> BM> == Bruce Momjian <root@candle.pha.pa.us>
|> 
|>  BM> If a hacker broke into a system, wouldn't he do his mischief, then
|>  BM> add entries to /etc/rc to truncate or modify the log files and then
|>  BM> cause a reboot.
|> 
|> Make /etc/rc immutable, and he won't.  (You want security?  Make LOTS of
|> stuff immutable.  Sure, it's a bit more of a pain to maintain, but it's
|> also a lot more of a pain to try to break into...)

Make /etc/rc run only commands and scripts that are either immutable or reside
on read-only filesystems.

Make / read-only.

Note: making / ro is actually possible *if* you have a seperate /var, a
seperate /tmp *and* provide appropriate soft links such as
/dev/log -> /var/dev/log so that syslog works. I tried this once, and the
system continued nicely. I don't see why / should be read-write...