40 new blogposts on my site advertising game downloads

Good morning.

Two days ago I received an email from my website host saying: “Malicious Attempt to Access Your Hosting Account is Detected.”

And: “We have put the following content into quarantine as we believe it contains
viruses or other malicious code:
wp-content/plugins/akismet/akismet.php”

I’m running WordPress v. 4.5.3 at this site:
https://nonprofit.csd-i.org/

Yesterday, on my website, what looks like a dated list of blog posts (an archive list or blog roll: August 2016, July 2016, June 2016 – going back a couple of years) appeared in my right sidebar. If you click on one of the links it takes you to advertisements for games and torrent downloads on blog posts installed on my site. These did not originate with me.

When I go into ‘Appearance’ widgets this archive list has been installed in my left sidebar—however my left sidebar is not activated. The archive list hasn’t been installed in a widget in the left sidebar – it’s in the main text of the description of the left sidebar where it says things like: “This widget area is currently disabled.” I can see it with firebug as an ordered list.

The next thing that happened is that I suddenly found 40 new blog posts relating to the new archive list.

I trashed all of them, and the archive list disappeared both from my website’s right side bar and also from the ‘Appearance’ widget area where it was visible in the left side bar.

<div id=”sidebar-left” class=”widgets-sortables ui-droppable ui-sortable”>
<div class=”sidebar-name”>
<div class=”sidebar-name-arrow”>
<h2>
</div>

Yesterday, I changed my login information at both the webhost (CPanel) and on my WordPress Admin Account. I also scanned my computer for viruses and found nothing.

Today, the dated archive list reappeared again in the right sidebar. I checked and I had a new blog post about a torrent download for an Adobe product.

Any ideas how to trouble shoot this?

Thanks in advance.

Tim Magee