This is the worm virus spreading via the Internet being attached to infected emails. The worm itself is a Windows PE EXE file about 107Kb of length, written in Visual Basic (VB5).
The worm activates from infected email only in case a user clicks on attached file. The worm then installs itself to the system, runs spreading routine and payload.
The infected messages have different texts and attached file names, they are randomly selected by worm while spreading from following variants:
Attach filenames are:
To send infected messages the worm scans *.EML, *.NWS, and *.DBX files, gets victim email addresses from there, then connects to SMTP server smtp.terra.es,then sends infected messages.
While installing the worm copies itself to Windows system directory with the REGWIZ.EXE name (and overwrites original Windows REGWIZ.EXE file in there),and registers this file in system registry auto-run key:
The worm also sets ReadOnly, Hidden and System attributes for this file.
The worm then displays fake error message:
The worm adds to C:MSDOS.SYS file the command:
The effect of this is unability to break or trace booting process under Win9x systems.
The worm then stays in Windows memory as hidden application (system service) and runs payload routine – the mouse cusror is randomly moved on the screen, and mouse becomes unusable.
The worm also runs its internal counter in the registry key:
and increases this valie on each run. When this counter reaches 75, the worm alteres the registry key:
then exits Windows and restarts the machine.