SEP Vulnerability BLOCKED, Attach Name: Portscan, Application: /mach_kernel

Problem

Symantec Endpoint Protection (SEP) for Mac detects /mach_kernel as a vulnerability and displays this notification.

Please note that this is an issue SEP and not an actual threat to your computer. The mach_kernel is legitimate.

To stop receiving this false vulnerability alert, you need to disable the notifications for this.

Open SEP from the Menu bar on the top of your Mac
Go to Symantec Endpoint Protection, then click Open Symantec Endpoint Protection
Go to Settings, then click Network Threat Protection or Intrusion Protection (varies depending on what version of Symantec is present)
Turn off Display Network Threat Notifications or Intrusion Protections as shown below. Do not turn off Network Threat Protection or Intrusion Protection, only the notifications.