nsbu.exe is a application which is most likely NOT a virus or malware. So, if nsbu.exe is on your system, it is most likely ok, and will NOT cause problems. Even if your system is clean, it is still recommended to purchase a good antivirus with a good track record, in order to defend yourself against viruses and malware.
This program is usually stored on disk in C:\Program Files (x86)\Norton Security with Backup\Engine\18.104.22.168\nsbu.exe.
The MD5 checksum for this executable is 82e38ae3aa0487d32f215797a41b39ee.
This program is set up as a Windows service. This means it operates on your PC in background, usually without showing any user interface to you. Most Windows services are legit programs, which perform useful functions to other programs or to Windows in general.
This program uses the Internet to communicate. In this day and age this is quite normal. For example, most of the apps on your computer check for updates. For this, Internet communications are required.
64-bit code has been detected. This program can exploit the full power of a current computer cpu.
The description present in the file is Norton Security with Backup.
File version 22.214.171.124.
Maker Symantec Corporation.
Legal copyright notice Copyright (c) 2017 Symantec Corporation. All rights reserved..
nsbu.exe appears to have visible windows. This is good because it doesn't work in some kind of invisible mode. Its operation is clearly displayed to the user.
nsbu.exe is digitally signed. Nowadays the large majority of serious programs are digitally signed.
The digital signature attached to nsbu.exe verifies as ok. This is very good.
Digitally signed by: Symantec Corporation
Certificate's issuer name: VeriSign Class 3 Code Signing 2010 CA
It has an uninstall string in registry, which is a good sign. si are uninstall.