Other examples of proprietary malware
Malware means software designed to function in ways that mistreat or harm the user. (This does not include accidental errors.) This page explains how Adobe software is malware.
Malware and nonfree software are two different issues. The difference between free software and nonfree software is in whether the users have control of the program or vice versa. It's not directly a question of what the program does when it runs. However, in practice nonfree software is often malware, because the developer's awareness that the users would be powerless to fix any malicious functionalities tempts the developer to impose some.
Adobe applications require periodic connection to a server.
Adobe tools require a subscription. Adobe also tried to rip people off by making the subscriptions annual, but that is a secondary issue compared with the basic wrong of the time bomb. When a program proprietary, and even malware, don't get distracted by the secondary issues like price.
Please don't repeat the marketing term “Creative Cloud” except to express revulsion for it. The term “cloud” is designed to cloud users' minds.
Adobe nonfree software may halt all other work and freeze a computer to perform a license check, at a random time every 30 days.
Adobe applications have time bombs: they stop working after a certain time, after which the user must pay to extend the time.
Once there was a problem with the servers that these programs use to check who has paid, and the applications refused to work for anyone.
Adobe made “Digital Editions,” the e-reader used by most US libraries, send lots of data to Adobe. Adobe's “excuse”: it's needed to check DRM!