Helvis is a trojan written with Visual Basic Script. The purpose of the trojan is to collect emails from the infected system.
Once detected, the F-Secure security product will automatically disinfect the suspect file by either deleting it or renaming it.
When this trojan is executed, it opens a web page using Internet Explorer. After opening the web site, the trojan attempts to drop a file to "c:\winnt\profiles\all users\start menu\programs\startup\VirusChecker.vbs". Because the path is hard coded, this file is dropped only in the default Windows NT installations.
Next the trojan collects all mails except a mail with subject "Halloween Elvis" from both inbox and sent mail folders from Outlook. These mails are sent to particular email address that propably belongs to the virus writer. The mail with the subject "Halloween Elvis" is deleted.
The "VirusChecker.vbs" file dropped into startup directory common for all users will be executed when the system restarts. With this file the trojan collects emails from the previous working day only. These mails are collected from user's inbox and sent mail folders and sent to the same email address mentioned above. On that way the trojan continues spying the infected machine.
Technical Details: Katrin Tocheva and Sami Rautiainen; F-Secure Corp.; November 1st, 2002