Name :	Somali.A
Category:	Trojan
Type:	Worm
Platform:	Win32
Date of Discovery:	August 28, 2006

Somali.A is a mass-mailing worm that terminates security-related processes and blocks antivirus-related software updates. This malware will only run on Windows platforms that have .NET framework installed.

Automatic Disinfection

Allow F-Secure Anti-Virus to disinfect the relevant files.

For more general information on disinfection, please see Removal Instructions.

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



It then drops several copies of itself:



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.



It 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.



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



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


- and drops a copy of itself on the said shared folder as Sound.exe.



The said shared folder has a share name of MadSoli, please see the sample image below:



Subsequently, it will create the following registry key:






Somali.A 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:



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:



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.


Payloads
Somali.A creates the following user in the local User Group:


Note: Run the following command from the CMD prompt to check for the said user: "net user NewAdmin".


It deletes all the subkeys on the following registry key:


- and displays the following Message Box every 19th of the month:

Detection

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