Mcon

Classification

Malware

Worm

VBS

Mcon, Sorry, TTFLOADER

Summary

VBS/Mcon is a worm that spreads via open network shares and mIRC.

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


Variant:Mcon.A

When the worm is executed, it first checks if the "Fonts" subdirectory in the Windows installation directory contains the worm. If the file is not found, the worm copies itself there using a filename "ttfloader.vbs". Then the worm executes the copy from the "Fonts" directory and deletes the original file.

If the original file was not named "ttfloader.vbs" or was not executed from the Windows' Startup directory the worm shows a message box with the following text:

FILE I/O ERROR
 

Next the worm will add itself to the registry, so it will be executed each time when the system is restarted.

Depending an a random number, the worm may change the Internet Explorer page to www.zonelabs.com.

The worm goes trough all drives in the system and if the drive is a local fixed disk, it copies itself to the root of the drive and to the following directories:


pub

 ftproot

 wwwroot
 

or if the name of the directory contains any of the following strings:


my

 download

 upload

 share

 game

 warez
 

The worm copies itself using a random file name taken from user's Recent directory, with a number of spaces and a ".vbs" extension appended to it. An attempt is made to hide the file by changing the file attributes as well.

It also removes following directories, if found:


chode

 foreskin

 dickhair 

If the drive is a network or removable drive, then VBS/Mcon.A copies itself to the root of the drive, and any directory that contains one of the following strings:

 my

 share

 download

 downloads 

Also, if Windows' Startup directory is found, the worm copies itself there as "ttfloader.vbs".

The worm deletes following files regardless of the drive

 mscfg.exe

 ashield.pif

 netstat.pif

 network.vbs

 mscfg.vbs

 winsock.vbs

 a24.vbs 

If VBS/Mcon.A founds a mIRC installation directory, the worm copies itself to the Windows' Fonts directory using name "sndload.vbs" and replaces the "script.ini" file with its own.

Next the worm chooses a random IP addess within some limits and uses the ping utility to check if a machine responds at that address. If the machine exist, it attempts to connect to each share on the remove machine.

If the connection is established, the worm will go through all directories in the shared drive copying itself there in the same way it does with removable and network drives above.


Variant:Mcon.B.

VBS/Mcon.B is modified variant of VBS/Mcon.A. The filename, that the worm uses in Windows' Fonts directory is changed to "ttfloads.vbs".

Additionally this variant copies itself to the Windows' System directory as "ttfload.dll".