An attacker could alter the amount of points that they receive. It has happened in the past with Folding@home, but they have put measures in place to prevent this from happening again. Although it isnt a guarantee that someone will not find a work around, we would become instantly aware and a patch could be put in place to correct the problem. https://folding.stanford.edu/home/faq/faq-points/#ntoc3

Each core is digitally signed for security reasons and authenticity of a real WU http://folding.stanford.edu/home/faq/#ntoc45