主动网络防御 决策者框架[20130222].pdf

F E B R U A R Y 2 0 1 3 P o l i c Y B R i E FActive Cyber DefenseA Framework for PolicymakersBy irving lachowAdvanced cyber attacks pose a serious risk to U.S.economic and national security.Passive cyber defenses1 that rely on perimeter sensors to prevent intrusions cannot adequately protect against increasingly sophisticated cyber attacks.Active cyber defense(ACD),a term that describes a range of proactive actions that engage the adversary before and during a cyber incident,can dramatically improve efforts to prevent,detect and respond to these sophisticated attacks.As a result,ACD activities are becoming increasingly common.One recent survey found that 36 percent of the 180 companies surveyed admitted to engaging in retaliatory hacking at least once and some people believe that the actual number is much higher.2 Yet even as ACD becomes more widespread,the debates about what techniques are appropriate or even legal are just beginning.One recent article in The Washington Post described ACD as“a con-troversial and sometimes ill-defined approach that could include techniques as aggressive as knocking a server offline.”3 Many of the public debates on the topic have focused on aggressi