Suh et al. (2004) propose a wonderful method for tracking taintedness, and denying dangerous operations.  It’s elegant, easy to understand, cheap in terms of performance hit, and effective.  The only problem is…  it would require re-designing the hardware (CPUs) to support it. 

I wish it would happen, but I’m not holding my breath.  Perhaps virtual machines could help until it happens, and even make it happen?