It's a supply-chain attack because the article has a section about how the official website for "Free Download Manager" was serving malware to a percentage of people.
> While checking videos on Free Download Manager that are hosted on YouTube, we identified several tutorials demonstrating how to install this software on Linux machines. We observed the following actions that happen in all these videos:
> - The video makers opened the legitimate website of Free Download Manager (freedownloadmanager[.]org) in the browser;
> - They afterwards clicked on the Download button for the Linux version of the software;
> - They were redirected to the malicious https://deb.fdmpkg[.]org/freedownloadmanager.deb URL that hosts the infected version of Free Download Manager.