Given the incredible modding scene that surrounded Grand Theft Auto IV, it seemed inevitable that GTA V would follow suit. So far, that seems to be the case, although it will probably take some time before some of the best mods will be seen. Nonetheless, with prospects of great mods also comes prospects of other people trying to ruin your day, by giving you something extra with that mod.
At GTAForum, user aboutseven notes that their PC was recently infected with malware, and after investigating, found that the source was a popular GTA V mod called Angry Planes. Since the post was made, many others joined in with confirmation, and another mod, called Simple Noclip, was also found to be packing malware.
It doesn't seem clear exactly what the malware does, but for the sake of precaution, it's being highly recommended that if you installed either of these two mods, you should get rid of them, scan your PC for malware, and then change your passwords. More in-depth steps can be found at the URL below.