W97M/Aleja is a Word macro virus.
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.
[Analysis: Sami Rautiainen, F-Secure]
