I just upgrade Confluence DC to 8.3.4 from 8.3.3 yesterday. (3/Nov/2023)
Then I find a plugin named "Web Shell Plugin" in user-installed apps.
I did not install this plugin manually.
I am not sure whether it is in the apps list, when Confluence DC is 8.3.3.
Is it a Atlassian plugin within Confluence DC itself? It seems a malware.
It's not a free plugin. I just disabled it.
And it's not a valid url when I click "buy now".
I could not find this plugin in Atlassian Marketplace.

Has my Confluence instance been hacked?