Somali.A is a mass-mailing worm that terminates security-related processes and blocks antivirus-related software updates.

Somali.A is also capable of opening a port on the infected machine. If a remote user sends strings to the opened port, the worm is able to reply to the remote user.

This malware will only run on Windows platforms that have .NET framework installed.

Execution

Upon execution, Somali.A modifies the registry so that the worm is executed every time a user logs on.

It then drops several copies of itself:


The worm also displays the following fake error messages:


Note: This message will appear on the first run on a clean machine.


Note: This message will appear if it has been run previously.

Propagation

Somali.A can also propagate through network. It does this by creating a Shared folder:


And then dropping a copy of itself on the shared folder as Sound.exe.

The said shared folder has a share name of MadSoli, as seen in the screenshot below:



Subsequently, it will create the following registry key:





Somali.A attempts to mass-mail itself using mx4.mail.yahoo.com as its SMTP server.

It searches for Yahoo! e-mail addresses on Windows folder in the files with the following extension names:



Possible Email address of the Sender:




Possible Subjects:



Possible Message Body:



Payload

Somali.A checks the running processes and terminates processes with the following strings:


The worm creates the following user in the local User Group:


Note: Run the following command from the CMD prompt to check for the said user:


It also deletes all the subkeys on the following registry key:


Somali.A displays the following Message Box every 19th of the month:



The worm also creates a HOST file named HOST.file in the %windir%\system32\drivers\etc directory. This HOST file will not allow accesses to the following sites:



Backdoor

Somali.A opens TCP port 8051. If a remote hacker connects to the said port and sends strings through this port, Somali.A will reply with the same string with all capital letters and adds exclamation mark at the end of the string.

Registry

Somali.A creates the following auto-run registry key so that every time the user logs on, Somali.A will be executed:


For its signature, it creates the following registry key:


It creates a Mutex named MadSoli so that there will be only one instance of itself in the memory.

Detection

F-Secure Anti-Virus detects this malware with the following updates:
[FSAV_Database_Version]
Version =  2006-08-28_04