The ethernet port LED (green) of my HP PageWide Pro Printer is constantly flashing in a very high frequency. Permanent, it seems to be 24 hours x 365 days even though the printer is not in use most of the time. This extreme flash is visible on the back wall and very annoying. I can't move the printer. I could cover the LED somehow but I really would like to know what the h*** this printer is communicating all day all year so that the ethernet port shows traffic with constantly flickering LED. No other web based device I own or ever owned did this. Can I stop it? Could it even be that something strange is going on (spyware)?
There's a pretty serious potential security exploit (CVE-2017-2741) for this (and other similar HP models) that could allow remote code execution.
If this device has been internet accessible and seems to be communicating with something, I would suggest investigating the following HP Security Bulletin, and taking steps to ensure that it is no longer vulnerable to this attack.