Summary

During early 1995, many PC users were confronted with a mystical "Pox on you" -message which appears on the computer's display when the machine was booted. When the matter was examined, the message was traced to an IDE driver file called CMD640X.SYS. The file comes with CMD PCI IDE drivers.

The message is not caused by a virus, nor has the original program file been tampered in any way. Rather, it seems that the driver's programmer has added a Trojan Horse routine to CMD640X.SYS as a "joke".

CMD640X.SYS activates randomly. It keeps printing the following message on the screen for a while, after which it crashes the computer.

        A poX oN yOu!! yoU wiLl bUrN iN tHe fiReS of HeLl!! A poX
        oN yOu!! yoU wiLl bUrN iN tHe fiReS of HeLl!! A poX oN
        yOu!! yoU wiLl bUrN iN tHe fiReS of HeLl!!

The only way to eliminate this nuisance is to install a sanitized version of the CMD driver into the computer.

[Analysis: Mikko Hypponen, F-Secure]