Hi, Nancy.
I’m going to answer your question out of our usual order…
The file you’re referring to is a failed upload file. You can probably just delete it.
As far as the unlikely number of new member registrations go - that can come about when you use the defaults built into EE - like the member register being at a predictable place with the default trigger word.
It won’t hurt to check the rest of your site for potential problems.. I’m posting a boilerplate response to you about what to do if you are hacked.
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Thanks for reporting this. We take security very seriously and will do our best to work with you on figuring out what’s going on. To that, we need some additional information from you…
1. EE version and build (found at the bottom of your control panel)
2. Other scripts on your account, whether in use or not (phpBB, etc…)*
* If this is a shared hosting environment, the host can make a determination if the attack came through scripts on another account on the server, which is commonly the case with these types of hacks.
While we work through this, please check through these files:
* path.php
* config.php
* index.php
to ensure that there is no unusual code such as iFrames or Javascript includes; if you do find that code, then please back-up the file and remove said code. If you are unsure of what does or doesn’t belong in these files, do not hesitate to ask.
You may also wish to refresh your files by following the build update instructions.
Also please ensure that you report this to your host immediately as they can help identify where the attack originated from so that steps can be taken to prevent this in the future.