Introduction to Cyber-Warfare - Proiect SEMPER FIDELIS

220 12. CYBER ATTACKS AGAINST POWER GRID INFRASTRUCTUREIn a power-grid network, this would mean that when a transmission substation fails, theload it normally carries is redistributed to other substations. This may cause the capacityof some of these other substations to be exceeded—causing them to collapse as well. An importantpaper by researchers from Arizona State University used a mathematical model toillustrate how this could happen. 21 The researchers investigated several attack strategies—in particular, they examined targeting of randomly selected, high-degree, and high-loadnodes in a network representing the power grid of the western United States. Interestingly,they found that targeting only a single high-load node tended to cause cascading failures(in addition to causing network fragmentation as described earlier), which theoretically couldresult in the connected component of that power-grid network to be reduced by over half ofits original size.Dependencies on Computer Networks Can Lead to Cascading FailureIn a seminal paper published in Nature, 22 a team of physicists introduced a new model (thatwe shall refer to as the “Buldyrev model”) for cascading failure in power grids. In this particularmodel, two infrastructure networks are considered, that of the power grid and that ofthe Internet. An outage in a substation will lead to an outage in certain routers on the Internet,which could potentially leave a transmission or control station unable to communicate andthus cause more substation outages. We illustrate this type of cascade in Figure 12.5.TInial configuraon:R = Internet routerS = Power substaonT = Power transmissionA staonDRSXRXSXRRSSTTransmission staonfailure leads tosubstaon failureRRTTSRSRTTRRSSRXSSubstaonfailure leadto loss ofpower torouterBEXRTRRSSubstaonfailureSSXleads torouterfailureTXXRRTTSRSRTTRRSSXRRouter failurelead to loss ofconnecvity totransmissionstaonCXSTRSRRRRouter failureleads to loss ofconnecvityFIGURE 12.5 (A) Initial power grid and Internet router network (S, power substation; T, power transmissionstation; R, Internet router). (B) A single power substation is targeted by a cyber attack. (C) The substation outagecauses a corresponding outage to the Internet router. (D) The outage of the Internet router causes a power transmissionnode to fail. (E) The failure of the transmission node leads to another substation outage. (F) The second substationoutage leads to more Internet routers failing.FXRXSXTXXSXTTSRRSTTRRSS