Re: Linux hacked
From: Jonathan Loh (kj6loh_at_yahoo.com)
Date: Wed, 20 Oct 2004 20:57:52 -0700 (PDT) To: "Nicholson, Dale" <DNicholson@APACMail.com>, firstname.lastname@example.org
Too bad your box was hacked.
Rather than depend on your sysadmin for updates. If you have root, write a
uname -a will get you the kernel revision
But since it's been compromised ....
You probably will want to rebuild your machine before you put the machine back
on the net.
rkhunter or rootkit will tell you if there's a rootkit installed. you may also
want to us aide (new tripwire) and nessus (vulnerability scanner).
--- "Nicholson, Dale" <DNicholson@APACMail.com> wrote:
> First let me say I'm a security novice. Please bear with me.
> My home linux (gentoo) machine was hacked last Thursday. Installed active
> on the box was ssh, apache, php 5, and a squirl mail. Iptables was set up
> for a firewall. The box was set up as a web server with a number of
> websites and about 35 email accounts (separate passwords for the mail than
> the user accounts on the box).
> I'm guessing it was some sort of script kiddie if the names taking credit
> for the hack in the hidden folders I found are any indication. I did some
> research on the person taking credit and found all kinds of information on
> him, he's an 18yr old kid in Germany. I doubt he is very knowledgeable or
> he would not have alerted me to the intrusion by somehow locking out all
> accounts from the machine.
> To get in I have to boot from cd and chroot in. Everything I've tried has
> been unsuccessful in getting root back.
> I found a hidden directory /var/tmp/.tmp that has a bunch of directories
> under it with names like +_01_+++++++HaXorEd by ... and
> I unplugged the machine from the internet shortly after the hack and can
> find no evidence of any uploads. I do see that the person somehow was able
> to break root. I was only able to find the hidden directories because the
> person forgot to clean up root's history file where I found the command used
> to create the them. The box was set up to not allow remote login of root
> via ssh but you could su in once logged in as one of three users.
> I'm a novice at security and had been depending on my system admin to keep
> the box up to date. He tells me he's been doing an emerge world every week
> but I don't know how to tell.
> Can someone help me with where to get a listing of everything I have
> installed and the versions? I can't remember if the kernel is a 2.4 or 2.6
> but I think it's 2.6. Plus I know there have been problems with ssh in the
> past but I don't know which versions have problems and I'm not sure how to
> find out what version I'm running. I'm kind of stuck as my sys-admin
> normally handles these things but he cannot ssh in to the box without me
> first fixing the problem since he lives 13 hours from me (the box is in my
> Also, I need something that can detect root kits etc. on linux. I've heard
> knoppix mentioned as having good tools on this list for an example, but I
> wouldn't know what tools to use for this particular case.
> This is what I tried so far:
> I logged in using a boot CD, mounted the hard disks, chrooted in, blanked
> out the root password in the /etc/shadow file, changed the root password,
> rebooted and tried to log in normally. This did not work. I also checked
> that the correct users were in both /etc/passwd and /etc/shadow.
> Note that both the email and websites were still working despite not being
> able to log in, although not now of course since I unplugged the ethernet
> Any comments/assistance will be greatly appreciated.
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