syssec_red_book

6. Critical Infrastructure Securitybe needed, something that is not even supported by most SCADA systems andtheir backbones.Subsequent milestones were Duqu (2011) and Flame (2012), both designedwith intelligence gathering purposes, although Flame is more opportunistic asit spreads also to mobile devices and uses ambient sensors (e.g., microphone)to steal information. These are two examples of the second most importantapplication of cyber weapons: espionage. Due to the similarity of some codefragments of Duqu, Flame and the variants of Stuxnet, it is not unrealistic toconclude that Duqu was designed to be the precursor of the next Stuxnet [127],to gather intelligence about CI targets.Whether Flame will be the precursor of the often predicted “year of cyberattacks (2013),” remains to be seen. As mentioned in Section 6.7, recentindustrial research efforts are moving toward this direction by deployinghoneypot ICSs to collect object evidence of attacks, which would be of help inanswering these questions.6.4 What Is the Worst That Can Happen?The discovery of Stuxnet, and the related events, concretelyshowed to the security the potential impactof attacks against CIs; this significantly increasedthe concerns and interest of the community. Today,vulnerabilities and attacks against CIs continue to bediscovered every week in the wild. A recent case isdated February 23, 2013, when the US Departmentof Homeland Security (DHS) reported that in a cyberattackagainst 23 natural gas pipeline operators,crucial information was stolen [71]. Although theDHS report, not yet disclosed to the public, does notmention the sources of the espionage, the digital signatures of the attackshave been identified by independent researchers as belonging to a particulargroup recently linked to China’s military (although China has denied theallegations) [72]. Unfortunately, these attacks will continue to spread. This iscorroborated by the increased amount of incidents reported and, more importantly,by the recent cyber-espionage cases, which are likely to be the precursorof more targeted and sophisticated attacks.In addition to (intentional) attacks and unintentional incidents in ICSs,which both impact the physical world, we believe that unintentionally causedfailures are also bound to happen. Instability, natural and artificial faults [259]or unexpected conditions in the physical systems, which eventually translateinto “signals,” processed by ICSs to take proper control actions, can44