Classification

Category :

Malware

Type :

Worm

Aliases :

Mobler

Summary

Mobler is a worm that attempts to copy itself to all available writable media (floppy, USB memory, different folders on fixed drives). It also disables certain Windows features and can perform a DoS (Denial of Service) attack.

Removal

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.

Technical Details

Installation to the System

After being run, the worm hides the Windows folder (sets a hidden attribute to it) and starts copying itself to different folders on local hard drives, and also to writable media with many different names. The names of the dropped copies of the worm can be "borrowed" from existing files and folders (e.g. windows.exe, system.exe) and can include a user name of an infected computer (e.g. Administrator documents.exe). The worm can also create a copy of itself with the name of Black_Symbian.SIS + Cracked By .exe.

The worm drops several files into the Windows System folder:

  • autorun.inf - an autostarter file pointing to system.exe file
  • black.app - a text file
  • black.html - an HTML file with a short message from the virus writer
  • black.ico - an icon file
  • black.jpg - an image file
  • black.txt - a text file
  • makesis.exe - a SIS archiver
  • system.exe - a copy of the worm

In the same folder, the worm creates an archive with the name Black_Symbian.SIS where it stores its executable file together with several additional files. Additionally, the worm creates a file named Black_Symbian.PKG where it lists the contents of the archive.

When active, the worm tries to constantly infect different devices with itself. For example, it constantly tries to copy itself to a floppy diskette and if the floppy drive is empty, it starts to produce constant noise because it is accessed too frequently. (Making for a strange type of sound from the computer.)

Payload

The worm disables Task Manager, Registry tools, viewing of folder options, and disables search. It also does not allow for the start of certain applications and for the running of files from the Start > Run submenu.

Mobler can perform a DoS (Denial of Service) attack on a website named: www.bsi.ac.id.