issues with security

Robert Meyer meyer_rm at
Mon Feb 2 13:26:39 EST 2004

Hmmm... sounds like either someone has gotten hold of your root password (you
never mentioned if you changed it) or has managed to create a root perms
account in your password file that got copied over or there is something in
your PHP code that is exploitable.  Cruise your PHP code and make sure that
it's not invoking any SetUID programs.  Also, make sure that you're not running
apache as user 'root'.  If the only thing that the firewall is allowing through
is port 80, then the next thing to do is to run apache in a chroot jail so that
it can't get at the O/S in any way.

Also, turn off ANY AND ALL services on the server that are not being used. 
This includes 'telnet', 'ftp', 'ssh' (if you're not using it), Email, SMB, etc.

I still would have a look at your firewall's rules to make sure that it's not
letting anything but port 80 through.

Turn on RedHat's internal firewall.  There are options when you do the install
to automatically firewall the machine and you can determine what ports are
allowed by the kernel.

Did I mention your firewall's rules? :-)


--- cliff at wrote:
> Hi Everyone,
> Apparently my first message didn't go through, so here I go again:
> I've been away from the list for a little while, but been having a major
> problem
> here at the office so I figured I'd post to see if you guys had any ideas...
> On the 22nd we had an issue with one of our systems that I thought had to do
> with
> some kind of hard drive error.  The system is a Red Hat Linux box, running
> primarily Apache and PHP to serve web sites.  I typically compile these
> things
> from source so I can have a little more control over configurability.
> Anyways, as it turned out, I noticed late last week that there were processes
> running that shouldn't be there.  After I killed the processes I noticed
> files in
> the /tmp directory, where PHP stores most of the session files (unless I tell
> it
> to store them somewhere else).  There was a 'blackhole.c' file and some other
> things which had been compiled to run on my system.
> I talked to my other programmer and we were going to come in Saturday to do a
> full re-install, but the hacker struck against Thursday night around 11 PM
> and
> defaced all of our sites.  I came into the office and spent the next 8 hours
> formatting, installing Red Hat 9, download all the newest source code for
> Apache
> and PHP, and getting everything set up.
> Well, I get into work today, and guess what?  Another bad process and more
> files
> in the /tmp folder.  I killed them all again, and am going to do *another*
> reinstall tonight.  I was e-mailing a colleague asking for his input so I'll
> post
> a few of the ideas I had for how the hacker got back in.  Here they are:
> (1)  I used the latest stable version of PHP, 4.3.4, when in fact there is a
> new
> version, 4.3.5RC1.  I wanted to avoid a release candidate version but that
> would
> be my first guess.
> (2)  Some other vulnerability I don't know about.  I installed the latest
> version
> of every other package so that's probably unlikely. Every other service is
> firewalled, so...
> (3)  I used the web backup from the morning of the 30th so as to not loose
> any
> changes - perhaps there was something in there that it allowing the hacker to
> gain access again.
> (4)  A problem with some of our PHP code.  Again, not sure how that's
> possible or
> what the issue might be.
> Does anyone have any other ideas?  Can anyone direct me (or offer) security
> consulting services to help take a look?  Is there any other information I
> can
> provide?  This is the first time I've really dealt with this and my blood
> pressure is through the roof... thanks very much guys.
> -Cliff Meyers

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