Hi!
After some investigation, we determined that the attacker had gained access via phpbb in a series of crafted URL requests, like so:
64.235.234.84 - - [20/Dec/2004:08:41:35 -0800] "GET /viewtopic.php?p=9002&sid=f5 399a2d243cead3a5ea7adf15bfc872&highlight=%2527%252Efwrite(fopen(chr(109)%252echr (49)%252echr(104)%252echr(111)%252echr(50)%252echr(111)%252echr(102),chr(97)),ch r(35)%252echr(33)%252echr(47)%252echr(117)%252echr(115)%252echr(114)%252echr(47) %252echr(98)%252echr(105)%252echr(110)%252echr(47)%252echr(112)%252echr(101)%252 echr(114)%252echr(108)%252echr(10)%252echr(117)%252echr(115)%252echr(101)%252ech r(32)),exit%252e%2527 HTTP/1.0" 200 13648 "http://forum.CLIENT SITE OMITTED.com/
If you cannot fix it (virtual servers) fast for all your clients you could also try with something like this:
RewriteEngine On RewriteCond %{QUERY_STRING} ^(.*)echr(.*) [OR] RewriteCond %{QUERY_STRING} ^(.*)esystem(.*) RewriteRule ^.*$ - [F]
We had some vhosts where this worked just fine. On our systems we didnt see any valid request with echr and esystem, just be gentle with it, it works for me, it could work for you ;)
Bye, Raymond.