[voltagex_]

Those Linux systems that aren't getting updates must be the ones sending Mirai to my Linux systems, which are getting updates (and also Mirai, although it won't run because it's the wrong architecture).

No malware? Only if you have your head in the sand.

[NegativeK]

I assume that comment was saying that they handle the update process and that their machines don't have any malware on them.

I ignored it because it was somewhat abusive and is missing the problem that automatic updates are trying to solve: that most people, but not all, don't do updates.