TSPY_MEXBANK.A

This spyware uses social engineering methods to lure users into performing certain actions that may, directly or indirectly, cause malicious routines to be performed. Specifically, it takes advantage the advantage of the controversial news about an allegedly missing four-year-old girl from Mexico. Upon investigation, it was found that the attack came from a Mexican botnet which aims to steal banking/financial-related information from users.

Upon execution, it drops the file, register.bat which terminates an existing svxhost.exe process, deletes the file and the registry associated with it. It then starts a new instance of the malware process.

Once executed, it performs several commands such as deleting of files, downloading and executing other malicious files, logging keystrokes to steal sensitive data, terminating applications and uploading of files.

This spyware executes commands from a remote malicious user, effectively compromising the affected system. It connects to a website to send and receive information. However, as of this writing, the said sites are inaccessible.

It executes the files it drops, prompting the affected system to exhibit the malicious routines they contain.

Arrival Details

This spyware may be downloaded from the following remote sites:

• http://{BLOCKED}botnetphp.com/ejecutable.exe

Installation

This spyware drops the following component file(s):

• %Windows%\WinSxS\x86_svxhost.VC90.MFC_1fc8b3b9a1e18e3b_9.0.30729.4148_x-ww_a57c1f53\register.bat
• %Windows%\WinSxS\x86_svxhost.VC90.MFC_1fc8b3b9a1e18e3b_9.0.30729.4148_x-ww_a57c1f53\register.vbs

(Note: %Windows% is the Windows folder, which is usually C:\Windows.)

It creates the following folders:

• %Windows%\WinSxS\x86_svxhost.VC90.MFC_1fc8b3b9a1e18e3b_9.0.30729.4148_x-ww_a57c1f53

(Note: %Windows% is the Windows folder, which is usually C:\Windows.)

Autostart Technique

This spyware adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
svxhost = "%Windows%\WinSxS\x86_svxhost.VC90.MFC_1fc8b3b9a1e18e3b_9.0.30729.4148_x-ww_a57c1f53\svxhost.exe"

Other System Modifications

This spyware adds the following registry entries as part of its installation routine:

HKEY_CURRENT_USER\Software\WinRAR SFX
%Windows%WinSxS%x86_svxhost.VC90.MFC_1fc8b3b9a1e18e3b_9.0.30729.4148_x-ww_a57c1f53% = "%Windows%\WinSxS\x86_svxhost.VC90.MFC_1fc8b3b9a1e18e3b_9.0.30729.4148_x-ww_a57c1f53"

It adds the following registry keys as part of its installation routine:

HKEY_CURRENT_USER\Software\WinRAR SFX

Backdoor Routine

This spyware executes the following commands from a remote malicious user:

• Download configuration file
• Delete files
• Send message via MSN messenger
• Download and execute other files

It connects to the following websites to send and receive information:

• http://{BLOCLKED}otnetphp.com/
• http://{BLOCLKED}tnetphp.com/
• http://{BLOCLKED}tnetphp.com/

It posts the following information to its command and control (C&C) server:

• IP address
• IP location
• Country
• Computer name

However, as of this writing, the said sites are inaccessible.

Dropping Routine

This spyware drops the following files:

• %Windows%\WinSxS\x86_svxhost.VC90.MFC_1fc8b3b9a1e18e3b_9.0.30729.4148_x-ww_a57c1f53\svxhost.exe - detected as TSPY_MEXBANK.SMI

(Note: %Windows% is the Windows folder, which is usually C:\Windows.)

It executes the files it drops, prompting the affected system to exhibit the malicious routines they contain.

Other Details

This spyware connects to the following URL(s) to get the affected system's IP address:

• http://www.ip-adress.com/

It does the following:

• Drops the file register.bat which terminates an existing svxhost.exe process and deletes the file together with the registry associated with it. It then starts a new instance of the malware process.
• It modifies the affected system's HOSTS if the location of the IP address is in Mexico.