Cyberwarfare countermeasures must consider more than technological capabilities. Attacks in cyberspace are commonplace. The effects of such attacks can range from minor nuisances, such as defacing webpages or temporarily denying service to noncritical systems, to major disturbances that interrupt international commerce or threaten to destabilize a nation-state. Anyone can wage an attack in cyberspace: individual citizens, criminal syndicates, terrorist organizations, even entire nations. Such attacks can be extremely sophisticated and involve many actors.The cyberattacks on Estonia in 2007 by so-called "patriotic hackers," criminal elements that leased out botnets, and alleged state-sponsored information warriors combined some of the characteristics of a military campaign with those of a covert operation.