Worm.Win32.VB.an is a worm that spreads using P2P-networks. It also tries to disable several applications on infected system.
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.
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 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.
Worm.Win32.VB.an usually comes as 'Setup.exe'. When the worms file is started, it creates a folder 'winupdates' in system programs directory and copies itself there as 'winupdates.exe'.
The worm installs the following registry key for ensuring it will be started in the next system startup:
[HKLM\Software\Microsoft\Windows\CurrentVersion\Run] "winupdates" = "%ProgramFiles%\winupdates\winupdates.exe"
The worm also writes the following files to the Windows system folder:
cmd.com regedit.com taskkill.com tasklist.com tracert.com ping.com netstat.com
The contents of these files are characters 'MZ'. As 'com' extension is evaluated before 'exe' in Windows program execution, this trick tries to disable the execution of above programs with 'exe' extension.
The worm tries to copy itself to several folders used by popular P2P software, such as Kazaa and Morpheus.