Good morning everyone

I have a problem, a very headache problem, with Apache2 on our server.  Our firm has a webserver that uses Apache2. It has been running excellent for many years until recently. One of our customers update their webpage and Apache2 keeps stopped responding at random hours.  restart doesn't work we have to kill the processor then restart then it will start but maybe 10 hours later it stops.

We have checked for an infinite loop on the customer's code and found nothing, there isn't any include inside include and for what I was told PHP prevent those include inside include to take any action anyway. We talked to our customer's programmer, he thinks it must be Dos Attack. But we have checked with the log and there is nothing as such.

I checked with bugs report on debian website, nothing mention about it. Our senior system admin believes there might be a funny code in our customer's script that cause this problem.

I'd like to help but my knowledge of PHP and Apache2 is very limited. Could someone give me a suggestion or a recommendation of what may cause these freezes and where I should look?

Many thanks in advance.