Its hard to believe that anyone would put faith in a Industrial Process system running on Microsoft Windows. Eyecurrent, explains:
Microsoft has posted an advisory about a new virus that seems to be specifically targeting Siemens WinCC through a Windows security hole, although users of other software shouldn’t feel smug about that, because there might be other strains affecting systems from other vendors as well. According to reports, the virus spreads via USB, keys and fully patched versions of MS Windows 7 are vulnerable. This is NOT the familiar “auto-run” vulnerability, so you’re not safe just because you’ve turned that off.
The really interesting point is that this appears to be specifically targeting industrial controls, rather than just the usual attempts by spammers to take over home PCs for botnets. If you are using this type of software, this is probably a story to keep an eye on.
Here is a link to the Microsoft Security Advisory: http://www.microsoft.com/technet/security/advisory/2286198.mspx
The saving grace is that these systems are typically firewalled and isolated from the real world.