Worm:VBS/AutoRun.B is a worm that spreads by copying itself to local hard drives, network drives, and removable drives.
It has no other functionality.
The worm contains four files:
The first file is the worm's Visual Basic Script file.
The autorun.inf file causes the __.vbs file to be executed when an infected drive is accessed with a computer that has autorun enabled on the drive in question.
The script copies all four files to the root of local hard drives, network drives, and removable drives not labeled A:\ or B:\. The four files are also copied under %windir%\system32.
The _.reg and _.bat files are detected as Trojan.Win32.Zapchast.ee.
If the script isn't being run from the %windir%\system32 location and therefore hasn't yet been installed, it executes the __.bat file.
The batch file (__.bat) installs the worm by creating the following registry entry to execute itself each time the computer is started:
- HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
Userinit = userinit.exe,__.bat
The batch file can make the registry changes by adding the contents of __.reg in to the registry. If the __.bat file was executed by the registry entry, it then runs the script file.
The batch file also sets the file attributes for all four files to hidden, system, read-only and archive.
The worm also tries to alter this registry entry:
This alteration is an attempt to make hidden files invisible in Windows Explorer.