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Date:      Mon, 17 Dec 2001 02:32:56 +0100
From:      "hjs" <hjs@thestof.com>
To:        freebsd-questions@freebsd.org
Subject:   Re: Strange Behaviour 'ls'
Message-ID:  <9vji09$3n5$1@news1.xs4all.nl>
In-Reply-To: <20011217012209.Z10171@md2.mediadesign.nl>

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Thank you for all your information.

I have disabled telnetd and am downloading 4.4.

If I run into probs, I'll let you know.

Kind Regards,
Stof

"Alson van der Meulen" <alm@flutnet.ORG> wrote in message
news:list.freebsd.questions#20011217012209.Z10171@md2.mediadesign.nl...
> On Mon, Dec 17, 2001 at 01:13:29AM +0100, hjs wrote:
> > Another thing I found....
> >
> > When I go to my FreeBSD box through ftp and go to directory /bin and do
an
> > ls, I see that two files have at least been touched (could have been me,
but
> > I am not sure) on December 13th. They are ls and ps. ps still seems to
work
> > though.
> >
> > Can I safely do a
> > make depend && make && make install
> > from their directories in /usr/src/bin or should I do something else to
> > rebuild them.
> I think your box has been trojaned, probably through telnetd, or
> possibly some other way:
>
ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-01:49.telnetd.v
1.1.asc
>
> ps and ls are often trojaned, ps hides probably certain processes the
> cracker runs, and ls some files. You can often see the files using
> `find' or `echo *', but you can't really trust _anything_ on that box.
> If possible, take that box offline immediatly, backup all _data_ (not
> binaries), and reinstall using 4.4-RELEASE. This box is possibly being
> used to crack/flood other computers or to serve warez.
>
> If reinstall really isn't a possibility, try installing chkrootkit
> (/usr/ports/security/chkrootkit) and try to find all files the attacker
> left, and the corresponding log entries. At least you should patch all
> security holes (http://www.freebsd.org/security/index.html)
> or upgrade to 4.4-RELEASE.
>
> This is NOT something that will be fixed by reinstalling ps and ls,
> since possibly more trojans are installed and they can get in the same
> way they used previously again.
>
> Please contact me if you have any more questions,
> Alson
>
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