Threat Description

Net-Worm:​W32/Koobface.BM

Details

Aliases:Net-Worm:​W32/Koobface.BM, Net-Worm.Win32.Koobface.bm
Category:Malware
Type:Net-Worm
Platform:W32

Summary



A type of worm that replicates by sending complete, independent copies of itself over a network.



Removal


Automatic action

Once detected, the F-Secure security product will automatically disinfect the suspect file by either deleting it or renaming it.

More

You may wish to refer to the Support Community for further assistance. You also may also refer to General Removal Instructions for a general guide on alternative disinfection actions.



Technical Details



This worm attempts to spread via the Facebook social interaction website.

Execution

Upon execution, the malware will check itself to determine if it is running as "c:\windows\bolivari19.exe". If it is not, it will drop a copy of itself named as bolivari19.exe and will execute the file.

Once executed, the malware checks its marker c:\windows\fmark2.dat to verify if has already been installed. If the file does not exist, the malware will display the following message:

  • Title: Error Message: Error Installing Codec. Please contact support.

It will then create the file.

Next, the malware checks for existing Facebook cookies, in preparation for its installation and propagation routine. If no cookie is found, the malware just terminates and deletes itself.

The worm will then perform a post request (POST /fb/first.php?[...]=0&v=20&c=1&s=fb&l=en&ck=1&c_fb=1&c_ms=0&c_hi=0post) to a220[...].com, to receive the necessary data, such as the URL link of the malware executable file.

Registry Changes

On installation, the malware creates a registry key that allows the malware to function on the infected machine.

Propagation

The malware propagates by using the cookie session of an infected Facebook user's account to post messages to people on the person's friends list. The message posted will include some tantalizing text such as "Someboody puload a vvldeo wtlh you on utubbe you hsould see", and a link.

The message content changes as new variations are downloaded by the worm during execution.

Clicking on the link leads to an external malicious website offering a (fake) YouTube video. The user is then informed that their "Flash Player is outdated" and they are prompted to "download an update". Doing so will download the malware's executable file.

This propagation method is effective because the message is supposedly posted by a friend. A person receiving such a message is far more likely to click the included link, greatly increasing the chances of infection. This propagation method also allows the malware to spread in the MySpace social interaction website, though based on its code, Facebook is its preferred propagation site.

In addition to posting messages to other users, the worm may also propagate by putting a link on the infected user's profile, which may also lead unsuspecting users to the malicious website.

Registry Modifications

Creates these keys:

  • HKEY_LOCAL_MACHINE\Microsoft\Windows\CurrentVersion\Run sysftray32 = c:\windows\bolivar19.exe





SUBMIT A SAMPLE

Suspect a file or URL was wrongly detected? Submit a sample to our Labs for analysis

Submit Now

Give And Get Advice

Give advice. Get advice. Share the knowledge on our free discussion forum.

Learn More