The overall reputation if your IP address matters more than a simple blacklist check:
Lookup for 107.182.166.86 - SenderScore.org
17 is terrible. You need to get that back over 80. It looks like you had a great score in the 90's until around 3 weeks ago.
From the graph it appears you're still suffering from bursts of spam from your IP address.
Who is responsible for keeping that wordpress up to date? If it's the client, I recommend you have them get their own web hosting so your sites don't suffer when their site isn't kept up to date.
Hi Ray,
Thanks for the reply. I apologize for not responding sooner. I wound up just dumping the server and getting a new one with new IPs. Namely because of this issue and I had a tech work to install ffmpeg, they had files strewn all over the place and it never worked. I wanted a fresh start.
Anyhow, I'm responsible for maintaining the WP install. If I don't manage it, I won't host it. You cannot depend on clients to be vigilant about updates. In the past year I've updated a couple of WP installs that were still running 2.x!
Once I caught the email issue I went through every folder in the account and found several php scripts with base64 encoding in the uploads folder. I neglected to check the wp-content/uploads folder when I did the original clean up. I rarely check /uploads as it's usually just pictures but this infection was particularly nasty. It placed PHP scripts named similar to WPs scripts all over the account (hard to detect) in addition to randomly named scripts which were easier to pin out. I wound up dumping all PHP files and manually uploading clean WP, plugin, and theme files. I had no problems after the more aggressive cleanup.
Finally, I moved this particular guy to a reseller account I have at a pretty awesome host. They have very strict email and abuse polices. I'm sure if there were still spam going out they would've been on my case by now.