[PLUG] Malware Webshell Infection. - Advice Needed

[Casey Bralla via plug <plug@lists.phillylinux.org>]

This morning, I received this eMail.  Originally I thought it was a scam, but looks like it might be true.  Here is the eMail (with redacted specifics)

Hello Casey,
Your cloud server that is hosting: [URL] and [URL] has been compromised on 2022-05-28 at 21:58, server time. I am not the threat actor, i stumbled across your server in a Shodan search.
Your server with IP [IP Address] and [URL] has directory listing enabled and you can see a webshell present there, wso.php, This probably happened because your server shares the webroot with rsync without authentication, someone used this to upload the webshell. The webshell has a default password of ghost287, is ran with the permissions of the www-data user so it's not possible to do heavy damage without escalating privileges but i highly encourage you to remove it to prevent further problems for your server.

Please answer if you need help to remove the webshell.

Kind regards

The file wso.php was present in /var/www along with another text file that looked like it had a password in it.  I've deleted those files.  But I'm wondering what my next course of action should be?

Should I completely shutdown and rebuild the servers (not too hard, I've got copies of the important files)?

Should I ask the author of this eMail for help as he offered?

Should I delete the 2 files and forget about it?

Obviously, I will be changing passwords, but could a bad person already have penetrated enough to see me change them and get the new passwords also?

Any advice would be appreciated.

-- 
LEGAL NOTICE:  This eMail contains private, personal, and/or privileged
information and is only for the intended recipient(s).  In fact, you
really should consider yourself honored to even be cc'd on this
tremendously important communication.  The author spent literally
seconds composing this magnificent opus of rational thought and
deductive logic.  Unfortunately, it has probably been based on
inaccurate data, which really stinks because this eMail would have been
truly awesome!  If you have received this eMail in error, we
respectfully DEMAND that you immediately delete it and inform the sender
that you have received it in error.  Then, just to be safe, you should
reformat your hard drive, shave your head, renounce all material
possessions (which are really controlling your life anyway), and join an
end-of-times cult somewhere.  Once there, you must reconsider all the
terrible choices you've made in your life, and promise never to confuse
"sex" with "gender" again.  Of course, this assumes you have already
come to terms with your inherent whiteness, AND that you have learned
the lyrics to The Internationale. "Arise, wretched of the earth!  Arise,
convicts of hunger..."
(https://en.wikipedia.org/wiki/The_Internationale)
We sincerely hope you are able to get your medication stabilized and no
longer have that recurring dream where you're alone in a large crowd,
standing naked in a vat of chocolate Yoo-hoo.  BTW, Yoo-hoo really is an
underrated beverage.  It’s chocolatey, yet suprisingly refreshing. Pick
up a 6-pack today, and tell your friends!

___________________________________________________________________________
Philadelphia Linux Users Group         --        http://www.phillylinux.org
Announcements - http://lists.phillylinux.org/mailman/listinfo/plug-announce
General Discussion  --   http://lists.phillylinux.org/mailman/listinfo/plug