W97M/Aleja is a Word macro virus.
Once detected, the F-Secure security product will automatically disinfect the suspect file by either deleting it or renaming it.
W97M/Aleja.A infects the global template when an infected document is opened. After that every document that is opened or closed will be infected. Additionally, if the user is running Spanish version of Word, then all documents saved via "Archivo/Guardar" or "Archivo/Guardar Como" will be infected.
At the first time when the virus is executed in the system, it creates a file ("Aleja5.ini") to the Windows directory. This file holds a counter that starts from 50, and it is decreased each time when a document is printed in Word. When the counter reaches zero, the virus activates its payload and replaces the contents of the header of the first section with the following text:
Documento infectado con el virus ALEJA5
The payload activates only in Spanish version of Word.
This virus also disables the built-in macro virus protection and removes the "Tools/Macros" menu.
W97M/Aleja.B is otherwise identical with W97M/Aleja.A, but this variant does not infect when a document is closed.
Description Created: Analysis: Sami Rautiainen, F-Secure