Syntax errors on all wordpress installs after upgrade

You need to start working your way through these resources:

• https://codex.www.ads-software.com/FAQ_My_site_was_hacked
• https://www.ads-software.com/support/topic/268083#post-1065779
• https://smackdown.blogsblogsblogs.com/2008/06/24/how-to-completely-clean-your-hacked-wordpress-installation/
• https://ottopress.com/2009/hacked-wordpress-backdoors/

Additional Resources:

• https://sitecheck.sucuri.net/scanner/
• https://www.unmaskparasites.com/
• https://blog.sucuri.net/2012/03/wordpress-understanding-its-true-vulnerability.html

Yes, I have already read all these files and followed all this advice following my original virus issue. This isn’t helpful!

You never came back to me so I didn’t know. Sorry!

Thanks for posting, Andrew!

DebraCuming: Wordfence doesn’t modify the core files, other than if you choose to have it restore any of the core files — the extra code added at the beginning is most likely from the ongoing infection. Since you said you’re reinstalling WordPress, that may fix some of the problems, but you will still need to find the original source of the hack. Were you able to do all of the recommendations in this guide? How do I clean my hacked site using Wordfence

The additional Wordfence options for high sensitivity scanning, and scanning files outside of the WordPress installation usually will find the source of the problem. Also, if you do have multiple sites under the same hosting account, make sure to run scans on all of them. (I think all of the header.php issues that we’ve seen resolved in the past couple of weeks were from additional sites that were outdated, or having an outdated plugin or theme on the site with the infection.)