seen on Shaan’s blog – Between the Lines
There is a virus being reported by a couple AutoCAD based product customers. The original virus first popped up in 2005 and was very limited but has been changed slightly. Some antivirus software does detect this virus and remove it. See below for the link to the technical solution.
The virus spreads simply by someone placing the malicious acad.vlx in a directory with the DWG files or a support path location being opened and then spreads from there into open DWG files and by replicating itself.