Update 9/18/2020: To future Googlers, this was determined to be an IT overreaction and I should not have posted it without proper research. The issue was likely our firewall incorrectly identifying a mirror server as malicious.
A few days ago I was installing Manjaro KDE on my laptop. I downloaded the manjaro-kde-20.0.3-200606-linux56.iso from the OSDN link, flashed it on Windows 10 using Rufus, and ran the install off of a freshly formatted flash drive.
I finished the install over my employer’s guest network, and within 5 minutes of booting into the system our IT director was in my office asking why a device called Manjaro was attempting to break through our firewall into the production network and install malware on the server. I immediately disconnected from WiFi, and wanting to get as far away from the issue as possible I downloaded ArcolinuxD, flashed it from my android phone, and installed that over Manjaro. My IT has confirmed no further suspicious activity since.
I am not sure whether the issue lies with Manjaro, or possibly with some pre-existing malware in my Windows 10 or Rufus installs, and since this is my personal machine I really don’t want to take any further risks to test this on our company network, and don’t really know how to identify the issue myself. I would really like to get my laptop running Manjaro, but I am nervous to try it again. Like an idiot, I did not verify the SHA1SUM of the ISO file, and the file was wiped out when I installed over Windows.
Since I am not really in a position to check in on this, so I wanted to put this out here in case someone with Manjaro wants to investigate. I am hopeful that any issues may have been eliminated with the new ISO that was just posted as I type this.