VB.AS

Classification

Malware

Trojan

W32

Email-Worm.Win32.VB.as, Worm.Gasop.B, W32.Berlity@mm, Email-Worm:W32/VB.as, Worm/VB.AS.11, W32/Gasop@MM

Summary

VB.AS, a variant of VB, is a Trojan. VB.AS collects email addresses and is used by spammers to send emails from infected computers. VB.AS modifies registry keys and shows fake error messages.

Automatic action

Based on the settings of your F-Secure security product, it will either move the file to the quarantine where it cannot spread or cause harm, or remove it.

Suspect a file is incorrectly detected (a False Positive)?

A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:

  • Check for the latest database updates

    First check if your F-Secure security program is using the latest detection database updates, then try scanning the file again.

  • Submit a sample

    After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.

    NOTE If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.

  • Exclude a file from further scanning

    If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.

    Note You need administrative rights to change the settings.

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Submit a sample

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Technical Details

Upon execution, VB.AS, detected as Email-Worm.Win32.VB.as, displays a fake message: "File Error: [number]".

It then creates copies of itself in the following folders as:

  • %Temp% - (usually C:\Documents and Settings\[user]\Local Settings\Temp\ )
    • Horror.vbe
    • LSASS.exe
    • Service.exe
    • SVCHOST.exe
    • Winword.exe
  • %SystemDrive% - (usually C:\ )
    • COMAND.com
    • Spiderman.exe

It also creates the following registry entries to automatically launch when Windows starts:

  • [HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run] AVPScaner "C:\Documents and Settings\[user]\Local Settings\Temp\"
  • [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run] HostNet Service "C:\Documents and Settings\[user]\Local Settings\Temp\"

Additional registry entry:

  • [HKEY_CURRENT_USER\Software\Microsoft\Symantecs\Ver] Ver " 50"

It also searches for possible email addresses from all htm files found on the harddrive. All gathered data will be saved in the registry as follows:

  • [HKEY_CURRENT_USER\SOFTWARE\Microsoft\Records\FileList] List of htm files scanned for email addresses
  • [HKEY_CURRENT_USER\SOFTWARE\Microsoft\Records\AdressList] List of email addresses gathered
  • [HKEY_CURRENT_USER\SOFTWARE\Microsoft\Records\Names] List of gathered names from the email addresses (ex. 'myname@' from myname@domain.com)
  • [HKEY_CURRENT_USER\SOFTWARE\Microsoft\Records\Servers] List of gathered domain name the email addresses (ex. 'domain.com from myname@domain.com)
  • [HKEY_CURRENT_USER\SOFTWARE\Microsoft\Records\AdressAlList] List of all possible combination of email addresses based from the gathered names and domains
  • [HKEY_CURRENT_USER\SOFTWARE\Microsoft\Records\Activar] Indicates that the malware is active
  • [HKEY_CURRENT_USER\SOFTWARE\Microsoft\Records\Scaneado] Indicates that the malware has performed scan

Notes:

  • %Temp% - usually C:\Documents and Settings\[user]\Local Settings\Temp\
  • %SystemDrive% - usually C:\
  • [user] - is the current user