1. Symantec/
  2. Security Response/
  3. Trojan.Norio


Risk Level 1: Very Low

September 4, 2003
February 13, 2007 12:23:36 PM
Also Known As:
TrojanDownloader.Win32.Small.b, Downloader-EA [McAfee]
Trojan Horse
Systems Affected:

Trojan.Norio is a Trojan horse that modifies browser and network settings to direct you to pornographic Web sites. This Trojan horse changes the default Explorer home page and search pages by modifying the registry.

The worm includes a component that can download and execute arbitrary code on your computer.

Note: At the time of this writing, this Trojan uses the file names, Winupdate.exe and Lookupsys.exe, in the Windows folder.

Antivirus Protection Dates

  • Initial Rapid Release version September 4, 2003
  • Latest Rapid Release version March 23, 2017 revision 037
  • Initial Daily Certified version September 4, 2003
  • Latest Daily Certified version March 23, 2017 revision 041
  • Initial Weekly Certified release date September 4, 2003
Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.
Writeup By: Heather Shannon

Search Threats

Search by name
Example: W32.Beagle.AG@mm
STAR Antimalware Protection Technologies
2016 Internet Security Threat Report, Volume 21
  • Twitter
  • Facebook
  • LinkedIn
  • Google+
  • YouTube