Some of the more recent studies implied that over 10,000 Department of Defense PCs were zombies. But the Pentagon pointed out its array of defenses, and the civilian security people took that and reexamined their data. The result is that it is currently believed that only about 7,000 U.S. government PCs are still zombies. That's only a fraction of one percent of all government PCs, and far below the general rate. The military PCs are less likely to be zombies, than are other government computers.
The military, especially in the U.S., but worldwide as well, are increasingly dependent on PCs and the Internet. Military nets are often more vulnerable than corporate ones, because companies usually have better management, and more effective safeguards against Cyber War threats. But the military is always looking out for attempts to penetrate their networks, and use several layers of defenses to stop the attacks. Most of these attacks are automated. Any PC on the Internet, no matter who owns it, will immediately be subjected to automated probes and penetration attempts. What's most interesting about these studies is that they show Chinese PCs nearly three times as vulnerable as American ones. Chinese military PCs are better protected than civilian ones, but that's because the Chinese military has separate units of specialists devoted to computer security, and how to breach it.
A recent flurry of claims and counter-claims by computer security firms about PCs that had been taken over by hackers, indicates that the military is doing a pretty good job at defending themselves against hackers. What kind of damage are we talking about here? Earlier this year, Microsoft revealed that a study it had done showed that 62 percent of infected (with a virus, etc) machines had a Trojan horse type program, that allowed someone else to take over that computer remotely, and turn it into a "zombie" for spamming or DDOS (distributed denial of service) attacks to shut down another site. What's interesting about this is that it indicates there are millions of zombie PCs out there. The more recent studies found that about one percent of PCs in the United States, and nearly three percent in China, are currently zombies.