On Fri, Apr 29, 2005 at 02:03:58PM -0500, Andrew Y Ng wrote:

> My server has been seeing some usual activities today, I don't have much time
> to get down to the bottom of things, but after I investigated briefly I have
> decided to disable PERL executable permission for www-data (Apache process's
> user), also locked /var/tmp so www-data cannot write to it.

Use chrot to protect your server slightly more against problems
with any buggy scripts.

This is almost certainly the result of an insecue PHP, Perl, or
other CGI script - rather than an Apache hack.

If you examine your webservers logs you might see where the
attack happened, perhaps you'll have entries invoking the
'wget' command to download the script you found from a remote
server - that's often a common attack.

If you're interested in protecting your server against input
designed to attack insecure applications you might wish to
investigate 'mod_security'.

mod-security homepage:
http://www.modsecurity.org/

mod-security under Debian example:
http://www.debian-administration.org/?article=65

> Looks like it ignores all the `kill` signals, not sure how I can actually
> kill it...

As root.

> here's d0s.txt:

Connects to an irc server, forking to make its name less obvious
on the process list.

Steve
--
# Debian System Administration
www.debian-administration.org/

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