Hi,
This piece of code was added to all php files with header.php, the wp-login.php file and a few others.
<div id="oaupbcygq"><img width=0 height=0 src="http://coffeescorer.com/count.gif?id=4cf1d54647353435fc00a677"></div>
I have removed this code, but what does it do and where did it come from?
Thanks
Have you checked your site's logs? Might give an indication for where.
Also what Plugins do you have on your site? 99.9999% of all plugins are safe but have found a couple that when activated place embedded links and they remain even if the plugin is removed. Or have you installed a hit counter? Or did someone else design your site?
It looks like its probably a hit counter. The width & height make it invisible. The count.gif could even be a non-existent file. The ID is probably for tracking by site. Everytime someone would view a page on your site it will generate a hit for the count.gif on the coffeescorer.com log.
If concerned about security:
http://codex.wordpress.org/Hardening_WordPress