Worm:W32/Mabezat.B, Win32.Worm.Mabezat.Gen, Worm.Win32.Mabezat.b, Mabezat.B, W32/Mabezat (McAfee), W32.Mabezat.B (Symantec), W32/Mabezat-B (Sophos), PE_MABEZAT.B-O (Trend Micro), Virus:Win32/Mabezat.B (Microsoft)


Worm:W32/Mabezat.B spreads through infected email attachments, removable drives and network shares.

The worm includes functionality to behave as a polymorphic file infecting virus, as it is able to infect executable files.

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.

For more Support


Find the latest advice in our Community.

User Guide

See the user guide for your product on the Help Center.

Contact Support

Chat with or call an expert for help.

Submit a sample

Submit a file or URL for further analysis.

Technical Details


On execution, the worm drops the following files into the system root drives:

  • %root%\autorun.inf
  • %root%\zPharaoh.exe

The autorun.inf file contains the following code:

  • [AutoRun] ShellExecute=zPharaoh.exe shell\open\command=zPharaoh.exe shell\explore\command=zPharaoh.exe open=zPharaoh.exe

The above process is used to automatically execute zPharaoh.exe, which contains the worm's executable code. It also makes the malware capable of propagating via removable drives.

The virus also creates the following folder:

  • C:\Documents and Settings\%currently logged-in user%\Application Data\tazebama

And may drop the file zPharaoh.dat into it.


Mazebat.B infects files in a polymorphic manner by appending data to a section of clean file code, then relocating the entire section together with the appended data. This action means that the altered code differs in every infected file.

The virus also adds garbage code to the file to 'pad' it and increase its polymorphism.


The worm modifies the Registry to disable certain functions.

It deletes this registry entry so that Autoplay is turned off:

  • HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer NoDriveTypeAutoRun = 00000091

It also creates this entry:

  • HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced ShowSuperHidden = 00000000