Apache2, unkown Logentries

Question

We are facing some strange issues on one of our webservers. It appears that the server is offline sometime for a couple of minutes which can go up to one hour. After investigating the logfiles I found many of entries like this

94.23.96.3 - - [23/May/2011:10:01:26 +0200] "GET /webdav/shell.php?act=phptools&host=69.x.x.x&time=120&port=80 HTTP/1.1" 302 260 "-" "-"
94.23.96.3 - - [23/May/2011:10:02:00 +0200] "GET /webdav/shell.php?act=phptools&host=69.x.x.149&time=120&port=80 HTTP/1.1" 302 260 "-" "-"
173.242.123.168 - - [23/May/2011:09:52:13 +0200] "GET /webdav/shell.php?act=phptools&host=24.x.x.x&time=120&port=80 HTTP/1.1" 302 260 "-" "-"
173.242.123.168 - - [23/May/2011:09:52:14 +0200] "GET /webdav/shell.php?act=phptools&host=24.x.x.x&time=120&port=80 HTTP/1.1" 302 260 "-" "-"
173.242.123.168 - - [23/May/2011:09:52:28 +0200] "GET /webdav/shell.php?act=phptools&host=67.x.x.xt&ime=120&port=80 HTTP/1.1" 302 260 "-" "-"
173.242.123.168 - - [23/May/2011:09:52:28 +0200] "GET /webdav/shell.php?act=phptools&host=67.x.x.x&time=120&port=80 HTTP/1.1" 302 260 "-" "-"
173.242.123.168 - - [23/May/2011:09:52:42 +0200] "GET /webdav/shell.php?act=phptools&host=99.x.x.x&time=120&port=80 HTTP/1.1" 302 260 "-" "-"
173.242.123.168 - - [23/May/2011:09:52:42 +0200] "GET /webdav/shell.php?act=phptools&host=99.x.x.x&time=120&port=80 HTTP/1.1" 302 260 "-" "-"

I checked the server and the apache root to clarify that the site isn't hacked. I didn't found anything.

Can somebody explain me what this is? And how we can stop this?

We are running an Ubuntu 10.04 LTS with newest updates

Apache Server version: Apache/2.2.14 (Ubuntu)

Answer 1

The opening IP is attempting to browse the pages /webdav/shell.php? as it's likely to be a known vulnerability. If you had such an application they would attempt to hack your server or use it in some way to spread their message.

It looks like you have an Apache rewrite in place to handle 404 pages (based on the 302 response code)..

Add the ip's to your iptables or firewall device...