Class Virus
Platform Win32

Technical Details

This is a per-process memory resident parasitic high-polymorphic Win32 virus. The virus infects PE EXE files that have .EXE, .SCR, and .CPL filename extensions. When run, the virus infects these files in current Windows and Windows system directories.

The virus also stays in the system memory as a component of the infected host program, gains access to KERNEL functions and intercepts 15 of them: file searching, opening, copying, moving functions, etc. When a PE EXE file is accessed by these functions, the virus infects it. As a result, the virus will infect all PE EXE programs that are accessed by the infected host program, and the virus will be active until the moment the host program exits.

While infecting a file, the virus encrypts its 8K code and is stored at the end of the file. Then the virus reads 8K of the victim file code, encrypts it and is also saved at the end of the file. That “cave” then is filled with virus polymorphic code
that decrypts the main virus code and passes control there:

File infection

 �=============�        �==============�
 �Header       �        �Header        �
 �-------------�        �--------------� <---- Program entry address
 �Code section � ---�   �Polymorphic   �
 �             �    �   �virus routine � ----� Jump to main virus code
 �             �    �   �--------------�     �
 �             �    �   �              �     �
 �-------------�    �   �--------------�     �
 �Data section �    �   �Data section  �     �
 �             �    �   �              �     �
 �-------------�    �   �--------------�     �
 �etc.         �    �   �etc.          �     �
 L=============-    �   L==============-     �
                    �   �Encrypted     � <----
                    �   �virus code    �
                    �   �--------------� 
                    L-> �Encrypted     � 
                        �hist file code� 

The virus’ polymorphic engine contains bugs and in some cases, the virus cannot decrypt its code, causing a standard Windows message about an error in the application.

On Fridays, and depending on the system date, the virus replaces StartPage for MS Internet Explorer and Netscape Navigator with a reference to the Web site:

The virus contains the “copyright” text:

[Virus TUAREG by The Mental Driller|29A]
– This virus has been designed for carrying the TUAREG engine –

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