Endpoint Protection

How can we judge that the file is virus file or normal?

If SEP catches it that would be a good indicator

You can also upload to ThreatExpert (owned by Symantec) to analyse:

http://www.threatexpert.com/

Or you can send to Symantec for review:

https://submit.symantec.com/websubmit/gold.cgi

Here are a bunch of tools to also help assist you in making a determination:

https://www-secure.symantec.com/connect/forums/your-system-infected-symantec-tools-help-clear-infection

About Symantec Help (SymHelp)

https://www.symantec.com/business/support/index?page=content&id=TECH170735

Hello,

Check its Reputation by either Running the Symantec Support Tool, check this Article:

Using Symantec Support Tool, how do we Collect the Suspicious Files and Submit the same to Symantec Security Response Team.

OR

Submit the file to the Security Response Team on:

https://submit.symantec.com/essential

OR / AND

on 

http://www.threatexpert.com/

Hope that helps!!

Agree with above comments.