Attacks on privately-owned parts of the NII could have serious effects on U.S. security. While the U.S. will likely be the first country with the ability to conduct widespread cyberwar attacks, given increasing global interdependence, particularly in cyberspace, those attacks could cascade across national borders and cause damage well beyond their intended targets. Such secondary effects could deter any widespread American use of cyberwar for offensive purposes. These attacks have led some commentators to sound the alarm that the U.S. is vulnerable to a major cyberattack. NII are undeniable, it is unclear how widely they can be exploited.
Hackers can gain access to many sites, but it is unclear how much damage they can actually do.
There are few public estimates available as to when countries will acquire widespread cyberwar capabilities the earliest appears to be 2005. In the meantime, national militaries and other groups can be expected to increase their ability to inflict damage in cyberspace. Whether the goal is financial gain or disruption, most attacks are concentrated on a single target. The widespread denial of service attacks of February 2000 provided a glimpse of the damage a future cyberattack might cause. A group of attackers operating in concert might effectively be able to shut down a number of computer systems at the same time.