Hello all,
It looks like someone hacked my apache2 server and I am trying to understand how this could have happened.
This is what happened:
All of a sudden the server - in response to a web-browser request for a page - started to give a full screen of unknown characters (looked like a long text with encoding mismatch).
The output was immediate and the same for all the web-sites located on the server.
Looking at the page source of the output I see the following:

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The address indicated in the begining of the page code leads to some chinese server.

So, somehow it happened that the output of the apache server was substituted by this page, which redirected visitors to some chinese server. It is the second time I am posting to the mailing list, the first time the mailing list virus scanner identified the content as having the Troj/Fujif-Gen virus, thus, this time I removed active links from the message body so it is not exactly what I received).

But the most strange thing was that the problem dissapeared itself! So, it last for 10 minutes then disappeared! And the again started and again dissapeared. Finally, I turned down apache untill I understand what is going on...

Any idea how could that happen?  How to reproduce this? How to prevent?
Where to look for logs? I have check both ssh logs and apache logs, there is nothing that could seem unusual there...

Any help is appreciated.