SONAR.Changeup!gen2 is a heuristic detection that is designed to detect W32.Changeup.

Initial Daily Certified version of virus definitions for Norton security products was released on June 4, 2013 revision 003. It should be noted that users with the older versions of Norton Internet Security are limited to Daily LiveUpdate definitions. For more information, go to the page where the are described virus definitions available for Norton products.

SONAR.Changeup!gen2 Threat Assessment

Component	Severity
Wild Level	Low
Number of Infections	0 - 49
Number of Sites	0 - 2
Geographical Distribution	Low
Threat Containment	Easy
Removal	Easy
Damage Level	Low
Distribution Level	Low

According to the Symantec Threat Severity Assessment, overall risk of SONAR.Changeup!gen2 is now categorized as «Low» — threat type characterized either as low or moderate wild threat (but reasonably harmless and containable) or non-wild threat characterized by an unusual damage or spread routine, or perhaps by some feature of the virus that makes headlines in the news. Read more about Threat Severity Assessment.

More information about SONAR.Changeup!gen2, you can find on the official site of Symantec Corporation, where in addition to useful information you can find technical details and removal instructions: www.symantec.com

It is also recommended to read the article Network security threats, where you can find a brief description and explanation of the most dangerous security threats plus a few simple tips on how to protect your personal computer from them.