1 Introduction

This chapter examines how a cyberattack (i.e., a cyber-enabled malicious activity) that has consequences similar to a kinetic or physical attack (causing serious loss of life or physical damage) could be encompassed within the crimes that may be prosecuted before the International Criminal Court (ICC). The chapter overviews when and how such a cyberattack could fall within the ambit of the ICC’s crimes – genocide, crimes against humanity, war crimes, and the crime of aggression. The chapter additionally acknowledges some of the limitations as to which attacks would be encompassed, given, particularly, the gravity threshold of the ICC’s Rome Statute, as well as the hurdle of proving attribution by admissible evidence that meets the standard of proof beyond a reasonable doubt. Notwithstanding such limitations, there is still potential for use of the Rome Statute to encompass a limited subset of cyberattacks. Increased awareness of this previous largely overlooked potential could possibly contribute to deterring such crimes, as could prosecution of those cases of cyberattacks that meet the standard of proof by required by the ICC Rome Statute. While it is very difficult to measure the deterrent impact of tribunals and international criminal law, whatever possible deterrence that can be created is certainly worth maximizing. This chapter explores how international criminal law could potentially contribute to the goal of reaching a state of “cyber peace.” Admittedly, the Rome Statute would not encompass the vast number of cybercrimes that occur, as it would only cover the more severe cyberattacks, such as those inflicting serious loss of life or significant physical damage; however, the Rome Statute does have applicability in this area to cover at least a limited subset of cyber operations, and this potential should be explored and utilized. The ICC can only help contribute to deterrence and cyber peace if the ability of the ICC to prosecute certain cyberattacks becomes acknowledged and well known.

2 Background

Cyberattacks can take a variety of forms including those aimed at data theft (stealing corporate information) (Griffiths, Reference Griffiths2015; as cited in Jensen, Reference Jensen2017, p. 736, n. 6), extortion, the spreading of false information (Greenfield, Reference Greenfield2013; as cited in Jensen, Reference Jensen2017, p. 736, n. 7), manipulation of elections (Hathaway et al., Reference Hathaway, Crootof, Levitz, Nix, Nowlan, Perdue and Speigel2012, p. 819; Ohlin, Reference Ohlin2020), breach of government computers in an effort to steal state secrets (O’Hare, Reference O’Hare2016; as cited in Jensen, Reference Jensen2017, p. 737, n. 8,), as well as denial of service attacks (U.S. Department of Homeland Security and the Cybersecurity and Infrastructure Security Agency [CISA], 2019). Such attacks sometimes proliferate beyond their intended targets to impact information technology (IT) systems around the globe, as with the infamous NotPetya attack (Greenberg, Reference Greenberg2018; Efrony & Shany, Reference Efrony and Shany2018, pp. 628–631). Further, the software code used in cyberattacks may also be “repurposed” by others (Bellovin et al., Reference Bellovin, Landau and Lin2017). Fortunately, to date, cyberattacks and cybercrimes have not resulted in widespread devastation causing loss of life and, to the extent physical damage has resulted, such damage has occurred more to data, computer hardware and software and, in one instance, to centrifuges at a nuclear facility (the Stuxnet attack). Cyberattacks have also caused massive economic losses (Greenberg, Reference Greenberg2018) and compromised the personal information of millions of individuals (Jensen, Reference Jensen2017, p. 737).

The use of cyber technology to date, however, makes clear that a much more catastrophic cyberattack could occur. States (on their own, or in conjunction with nonstate actor/hacker groups) now have the capacity to combine cyber weapons with conventional weapons into a “blended attack,” such as occurred in Ukraine (Greenberg, Reference Greenberg2018) and Georgia (ICC Forum, 2018). A number of war crimes that could be committed during a conventional armed conflict could now, potentially, also be committed through the use of cyberattacks or through both cyber and conventional means. Absent a state of armed conflict, cyberattacks meeting the requirements of, inter alia, a widespread or systematic attack against a civilian population could fall within the ambit of “crimes against humanity.” For example, the technological capacity to disable air traffic controls exists, causing a “cyber 9/11” – perpetrated, for example, by nonstate actors (cyber criminals or bands of hackers). A cyberattack could similarly target computer systems that control train traffic, nuclear facilities (Greenberg, Reference Greenberg2017a), hospitals (Glaser, Reference Glaser2017; Mačák et al., Reference Mačák, Gisel and Rodenhäuser2020), power grids (Greenberg, Reference Greenberg2017b, Reference Greenberg2018), and other critical infrastructure – or, for example, a dam located upstream from a major city (Berger, Reference Berger2016). It is this narrow subset of cyberattacks – causing serious loss of life and/or physical destruction – not the vast number of cybercrimes being perpetrated – that this chapter addresses.

While one hopes that a large-scale cyberattack, or even a more limited one that causes serious loss of life or damage to physical objects, will never reach fruition, it is simultaneously helpful to acknowledge that should such an attack occur, it potentially could be covered by one or more of the crimes provided for under the ICC’s Rome Statute. States, particularly Rome Statute States Parties, could also incorporate Rome Statute crimes into their domestic criminal codes and statutory law (if they have not already done so), and/or develop additional laws criminalizing cyberattacks and/or cybercrimes. Should they do so, domestic definitions of the crimes could be more broadly formulated than their Rome Statute counterparts and have greater jurisdictional reach; thus, the limitations of the Rome Statute discussed in this chapter do not necessarily carry over to domestic jurisdictions. While the international community could also create a new international criminal tribunal to deal exclusively with cybercrime and cyberattacks, in light of the apparently unwillingness to create new criminal tribunalsFootnote ¹ this chapter focuses on the permanent international criminal tribunal that already exists, the ICC.

3 Maximizing the Potential for Cyber Peace through Deterrence

The goal of the present chapter is not only to make the case for ICC cyber prosecutions should a horrific attack occur but to increase awareness of the potential for ICC prosecutions in order to maximize the potential for deterrence as a means to contribute to achieving a state of “cyber peace” (see Shackelford, Reference Shackelford2017, p. 8, defining “cyber peace”). It is important that the cyber domain is not seen as unfettered by the rule of law, when it is in fact subject to numerous bodies of international law (UK Government, 2018; Koh, Reference Koh2012, p. 3), including international humanitarian law (aka the laws of war) (Schmitt, Reference Schmitt2017, Rule 80; “The Paris Call,” 2018), international human rights law (Schmitt, Reference Schmitt2017, Rule 35), as well as the use of force norms contained within the UN Charter as supplemented by customary international law (Schmitt, Reference Schmitt2019 (citing position of France, and the UK Government, 2018, noting also that Russia and China accept that the UN Charter applies in cyberspace)). The more well acknowledged it is that international humanitarian law and international human rights law apply in the cyber domain, the easier it is to make the case that certain cyberattacks are covered under international criminal law. Even if the application of current bodies of international law to cyberattacks may not prove an “elegant fit,” it is imperative to utilize the laws that exist and/or develop additional laws (cf. Rona, Reference Rona2003, p. 60, arguing International Humanitarian Law (IHL) should apply to the “war on terror” even if “not an elegant fit”).

Significant academic literature exists on the subject of whether international criminal law can play a deterrent role and whether the existence of the various ad hoc and hybrid criminal tribunals has contributed to deterrence and/or the ICC can do so.Footnote ² Various scholars take a pessimistic stance as to the potential of tribunals to deter atrocity crimes (McAllister, Reference McAllister2019–20, p. 85, n. 2, categorizing scholars as “deterrence pessimists”). Yet, increasingly, there are scholars whose studies yield positive results (McAllister, Reference McAllister2019–20, p. 85, n. 4, categorizing scholars as “deterrence optimists”). For example, a recent study, based on over 200 interviews, demonstrates that Macedonian Armed Forces, during the 2001 conflict in Macedonia, considered the existence of the International Criminal Tribunal for the former Yugoslavia (ICTY) when deciding their actions (specifically, whether any could be viewed as war crimes), and this deterred violence against civilians (McAllister, Reference McAllister2019–20; see also Schense & Carter, Reference Schense and Carter2017). Similar studies show some deterrence created by the existence of the ICC (Jo & Simmons, Reference Jo and Simmons2016; Hillebrecht, Reference Hillebrecht2016; Human Rights Watch, 2009, Ch. IX).

It is worth noting that domestic criminal law also does not fully deter domestic crimes; yet states nonetheless criminalize crimes, from murder to insider trading. So too with international criminal law. As Brierly observes: “States often violate international law, just as individuals often violate municipal law” (Brierly, Reference Brierly1944, pp. 4–5). Clearly, the field of international justice has not yet fully deterred crimes such as genocide, crimes against humanity, or war crimes, as these crimes still occur far too often. Furthermore, it is also notoriously hard to prove a negative – that is, that crimes have not occurred due to the deterrent impact of tribunals or international criminal law – so there could actually be more deterrence than can be conclusively demonstrated. Yet, the case that one should not criminalize atrocity crimes is generally not made; clearly, whatever role deterrence can play is worth maximizing, and if international criminal laws and tribunals are incapable of deterring or not fully capable of doing so, then at least the laws exist whereby the crimes may be prosecuted. In short, international criminal law is one of the tools at the disposal of those working in the field of international justice, and while it may not fully deter, any deterrence potential is useful. As Guido Acquaviva writes: “international criminal institutions” that “strengthen[] the rule of law and pursu[e] individual criminal responsibility” “can increase awareness of the primary rules … among the general public and … foster compliance with the law and therefore, indirectly, general deterrence” (Acquaviva, Reference Acquaviva2014, p. 786).

The United States, for instance, suggests that the prosecution of cyberattacks can change behavior. Kristen Eichensehr explains:

Eichensehr notes that: “After the first U.S. attribution-by-indictment – the charges against Chinese [People’s Liberation Army] officers for intellectual property theft – sources indicated that the Chinese military substantially scaled down its economic espionage activities. But at the same time, [Eichensehr admits] state-sponsored hacks of many kinds have continued after indictments” (Eichensehr, Reference Eichensehr2020, p. 553). Eichensehr also discusses what she calls “micro-level deterrence” against particular individuals who are deterred from future violations through indictment or the imposition of sanctions (Eichensehr, Reference Eichensehr2020, pp. 554–555). Certainly, the potential for deterrence is maximized through the use of international criminal law, which has the potential to contain far more stringent sanctions than simply “naming and shaming” – that is, simply publicly attributing the source of the cyberattack.

That said, as mentioned, the ICC cannot play a role in deterring cyberattacks unless actors (both state and nonstate actors) realize that certain cyberattacks, even if only a limited subset of them, could constitute Rome Statute (or other) crimes. In this respect, one welcome initiative is the convening of the “Council of Advisers on the Application of the Rome Statute to Cyberwarfare,” a group of expert participants convened by the Permanent Mission of Liechtenstein to the United Nations and co-organized by Argentina, Austria, Belgium, Costa Rica, the Czech Republic, Estonia, Luxembourg, Portugal, Spain, and Switzerland, as well as the Global Institute for the Prevention of Aggression (“Council of Advisers,” 2021). The goal of the group is to increase awareness of the potential for the Rome Statute to cover certain cyberattacks through its meetings and the eventual release of a report (see also Digital Watch discussing the Open Ended Working Group on Cybersecurity at the UN). (The author serves on the Council of Advisers.)

It is not claimed that this increased knowledge will fully deter cyberattacks that could be encompassed by the Rome Statute; in particular, one would expect less deterrence in situations where no ICC jurisdiction exists, and where one would not anticipate the Security Council referring a situation to the ICC (see the Rome Statute, 1998, Arts. 12(2)(a)–(b), 13(b), 15bis, 15ter on jurisdiction).Footnote ³ For example, it would be naïve to anticipate referral by the Security Council of a situation to the ICC (which is permitted, Rome Statute, 1998, Arts. 13(b), 15ter), if a permanent member of the Security Council is involved in a cyberattack. (The permanent members hold veto power over substantive Security Council votes, UN Charter, Art. 27(3)). Additionally, it might be difficult to deter informal or rogue bands of hackers who might remain unaware of any expert report on cyberattacks (or even the ICC’s existence), and perhaps would not be deterred regardless. An additional argument could be made that the ICC would have to become a more effective institution before it creates significant deterrence – for example, it has a significant number of outstanding arrest warrants (see ICC Warrant/Summonses, n.d.). Furthermore, that the ICC tends to focus its prosecutions on higher-level perpetrators further suggests that “ordinary hackers” would not necessarily fall within its focus absent an egregious cyberattack, and so decreases any deterrence potential to “ordinary hackers.” Yet, the ICC is not limited to prosecuting only those bearing the “greatest responsibility” for statutory crimes, as was, for example, the Special Court for Sierra Leone (Special Court Statute, Art. 1.1); thus, if a particularly egregious cyberattack were to occur, an “ordinary hacker” could potentially attract the ICC Prosecutor’s focus, including, potentially, all who aided and abetted the crime or who acted with the “common purpose” of committing the crime.Footnote ⁴ Notwithstanding, as mentioned, the initial first step in attempting to maximize deterrence – and thereby potentially contributing to the goal of achieving a state of cyber peace – is most certainly to create broader awareness of the ICC’s potential to prosecute a limited subset of cyberattacks.Footnote ⁵

The section below briefly considers two initial overarching considerations that restrict the cyberattacks the ICC might be able to prosecute. The following section provides a brief overview of how certain cyberattacks could fall within the Rome Statute’s substantive crimes – war crimes, crimes against humanity, genocide, and the crime of aggression. A more expansive discussion of both topics can be found in my forthcoming article “The Criminalization of Cyberattacks under the International Criminal Court’s Rome Statute” (Trahan, forthcoming) and the upcoming Report of the Council of Advisers on the Application of the Rome Statute to Cyber Warfare (forthcoming).

4 Overarching Considerations as to ICC Prosecutions

Some of the limiting factors in terms of prosecuting cyberattacks before the ICC include (1) the Rome Statute’s “gravity” threshold and (2) the need to prove attribution through admissible evidence that could satisfy the standard of proof beyond a reasonable doubt. While they are beyond the scope of the present chapter, additional limiting factors include the need to satisfy jurisdiction; the ICC’s “intent” requirement (which excludes responsibility for unforeseen consequences and severely restricts it even as to foreseeable consequences);Footnote ⁶ and the prohibition in the Rome Statute on expanding definitions of crimes by analogy, with ambiguity construed to favor the defense (Rome Statute, 1998, Art. 22(2)). (For a discussion of all three topics, see Trahan, forthcoming.)

5 The ICC’s Gravity Threshold

For a case to be “admissible” before the ICC, Article 17 of the Rome Statute requires that it be of “sufficiently gravity to justify … action by the Court” (Rome Statute, 1998, Art. 17(1)(d)). Article 53 further states that the Prosecutor may only initiate an investigation or proceed with a case if it “would be admissible under Article 17” (Rome Statute, 1998, Arts. 53(1)(b), 53(2)(b)). These provisions raise the question of which cyberattacks would be considered more grave and which less grave, or of marginal gravity. The ICC’s cases to date have focused on rather large-scale crime scenes, with the “smaller” crime scenes probably being the killing of twelve peacekeepers, at issue in the Abu Garda case (see Whiting, Reference Whiting2015),Footnote ⁷ and the destruction of nine mausoleums and one mosque at issue in the Al Mahdi case (Prosecutor v. Al Mahdi, Case Information Sheet, 2018). Both cases involved the killing of persons or the destruction of physical objects.Footnote ⁸

In terms of evaluating the gravity of cyberattacks, a useful starting point for analysis is Tallinn Manual 2.0 on the International Law Applicable to Cyber Operations (Tallinn 2.0). Admittedly, there are divergent views among states and experts as to the weight to accord the Tallinn Manual (Efrony & Shany, Reference Efrony and Shany2018), and in any event they are not binding on the ICC, yet they can at least provide a useful starting point.

In Tallinn 2.0, the experts focused on what constitutes an “armed attack” committed through cyber means. They engaged in this analysis because an “armed attack” can justify self-defense under Article 51 of the UN Charter (see UN Charter, Art. 51); they were not engaging in this analysis in relationship to the ICC. Tallinn 2.0 takes the position that “a cyber operation that seriously injures or kills a number of persons or that causes significant damage to, or destruction of, property would satisfy the scale and effects requirement” and thus constitute an “armed attack” (Schmitt, Reference Schmitt2017, Rule 71, para. 8.) This would provide one possible standard by which to evaluate the gravity of cyberattacks. Namely, only if a cyberattack seriously injures or kills a number of persons or causes significant damage to, or destruction of, property, would that satisfy Rome Statute gravity.

The experts additionally suggested various criteria that “States are likely to consider” as to when a cyber operation constitutes a “use of force” (relevant to considering when Article 2(4) of the UN Charter is violated, see UN Charter, Art. 2(4)). These criteria included severity, immediacy, directness, invasiveness, and measurability of effects (Schmitt, Reference Schmitt2017, Rule 69, para. 9 (a)–(e)). These would appear useful criteria to consider in making the gravity evaluation. Additional factors that could prove useful for consideration include those identified in ICC case law (see, e.g., Prosecutor v. Al Hassan, 2020, paras. 59, 89, 90) and by the Prosecutor (see “Policy Paper on Preliminary Examinations,” 2013, paras. 62, 64–65).

Another interesting consideration is whether loss of life or physical destruction is always the most grave of harms? For instance, France takes the position that operations that penetrate military systems to weaken French defensive capabilities, even if this does not produce physical effects, would constitute a “use of force” (Droit International, 2019, as cited in Schmitt, Reference Schmitt2019).Footnote ⁹ Similarly, the Netherlands takes the view that a catastrophic systems attack that causes very serious economic impact could constitute an “armed attack” (Schmitt, Reference Schmitt2019, quoting the Dutch Minister of Defence). While neither country is opining on whether such conduct would meet Rome Statute gravity, it is worth considering whether it should do so. The author suggests that here one might differentiate between penetration of military systems and catastrophic systems attacks that cause serious injuries or fatalities to persons, or significant damage to or destruction of property, from those that do not. Another interesting question is whether the destruction of “data” should be encompassed, or whether the “property” destroyed would need to be physical property (see, e.g., Biller and Schmitt, Reference Schmitt2019; Mačák, Reference Mačák2015; Horowitz, Reference Horowitz2020, considering destruction of data).

The ICC might wish to examine these issues and consider issuing a policy paper on application of the Rome Statute to cyberattacks (including the topic of gravity). At the same time, in terms of increasing deterrence potential, there could also be some advantages flowing from ambiguity. Thus, this author suggests that one possible gravity threshold for ICC prosecution could be where a cyberattack causes serious injuries or fatalities to persons or significant damage to or destruction of property; at the same time, perhaps one would not want to close the door to other large-scale or invasive attacks that do not meet this definition. Also, as the ICC Appeals Chamber explains in the Al Hassan case, the gravity requirement does not “oblige the Court to choose only the most serious cases, but merely [obliges] it not to prosecute cases of marginal gravity” (Prosecutor v. Al Hassan, 2020, para. 59).

The ICC’s pursuing of a case where a cyberattack of sufficient gravity occurs would be significant in itself, and make clear that the Rome Statute does encompass cyberattacks. Roscini writes: “the Prosecutor might decide to select certain situations and cases involving the commission, instigation, or facilitation of international crimes through cyber conduct because of their impact or to deter them in the future, even if they resulted in a lower number of victims than in other cases” (Roscini, Reference Roscini2019, p. 271).Footnote ¹⁰ This “expressivist” approach – pursuing prosecutions that further protected values and thereby sending a message to achieve a given result – is indeed an important and legitimate aspect of prosecutorial strategy (Cross, Reference Cross2020, pp. 67–68).

6 Proving Attribution through Admissible Evidence that Establishes Proof Beyond a Reasonable Doubt

An additional limiting factor – true for all ICC crimes – would be that all the elements of the crime would need to be proven through admissible evidence that could eventually satisfy the requirement at trial of proof beyond a reasonable doubt (Rome Statute, 1998, Art. 66(3)). This includes the issue of attribution (who conducted the cyberattack), sourcing it not just to a state (or nonstate actor/hacker group working for the state) but potentially to a particular “computer, … to identify the person who operated the computer, and more importantly to identify the real ‘mastermind’ behind the attack ….” (Tsagourias, Reference Tsagourias2012, p. 233). This could pose significant challenges (Dederer & Singer, Reference Dederer and Singer2019, p. 438 (citing sources)).

Compounding difficulties, cyberattackers sometimes go to lengths to conceal cyber operations (Hathaway et al., Reference Hathaway, Crootof, Levitz, Nix, Nowlan, Perdue and Speigel2012, p. 843), and states sometimes deliberately hide their attack as perpetrated by another state (“false-flagging”). For example, this happened when “Russian hackers piggy-backed on an Iranian cyber-espionage operation,” thereby hacking into “government and industry organizations in dozens of countries while masquerading as attackers from the Islamic Republic [of Iran]” (Stubbs & Bing, Reference Stubbs and Bing2019). Or states can hide behind nonstate actors to mask their operations (Dederer & Singer, Reference Dederer and Singer2019, p. 438; Hathaway et al., Reference Hathaway, Crootof, Levitz, Nix, Nowlan, Perdue and Speigel2012, p. 854). Even when that is not the case, because cyberattacks can be perpetrated through a single computer or network of computers located far from where the consequences impact, they can be extremely difficult to attribute (Dederer & Singer, Reference Dederer and Singer2019, p. 431; Brenner, Reference Brenner2011, p. 32). The attacks can also be concealed by feigning that operating systems are functioning normally (Rowe, Reference Rowe2007; Hathaway et al., Reference Hathaway, Crootof, Levitz, Nix, Nowlan, Perdue and Speigel2012, p. 828).

Furthermore, if attribution is to be made, this raises questions as to who would be in a position to do so. Would this be practical for the ICC to do itself? And, if not, what are the implications of relying on state cooperation in this regard? In addition to attribution, all of the evidence in the case would require “authentication,” and this (and simply having the knowledge to assemble a cyberattack case) would require significant technical expertise. Relying on state cooperation also carries pitfalls in that states may be more likely to cooperate when it suits their self-interests (e.g., they have suffered from a cyberattack), and not cooperate when it does not serve their interests (e.g., they were the perpetrator or linked to the perpetrator). Thus, there will be significant challenges in terms of attribution, authentication, and development of the necessary expertise to establish both. Building ICC expertise will require both the hiring of staff, and/or use of outside experts, and development of relevant policies.

Thus, the above discussion suggests the potential applicability of the Rome Statute to a limited subset of cyberattacks: (1) if they meet the Rome Statute’s gravity threshold and (2) where attribution could be proven beyond a reasonable doubt. As mentioned, other limiting factors include whether jurisdiction exists; whether the “intent requirement” can be proven (which appears to exclude responsibility for unforeseen consequences and limit responsibility even for foreseen consequences);Footnote ¹¹ and whether the crimes can be applied without drawing on analogies, with ambiguity construed to favor the defense (Trahan, forthcoming).

7 The Rome Statute’s Substantive Crimes

Despite the limitations suggested above, the next section outlines the key elements of the Rome Statute’s four core crimes – genocide, war crimes, crimes against humanity, and the crime of aggression – and suggests how a limited subset of cyberattacks might fall within the definitions of each.Footnote ¹² Again, domestic jurisdictions, even ones that incorporate these crimes into their domestic criminal codes, could adopt broader definitions of the crimes; thus, the elements of the crimes discussed below would not necessarily apply in domestic jurisdictions, which also might have or develop broader criminal statutes covering cyberattacks and/or cybercrimes.

8 Cyberattacks as War Crimes under the Rome Statute

As mentioned, the rules of international humanitarian law apply in the cyber domain (Schmitt, Reference Schmitt2017, Rule 80; “The Paris Call,” 2018). Thus, for example, Tallinn 2.0 explains that in a state of armed conflict, cyberattacks may not target civilians (Schmitt, Reference Schmitt2017, Rule 80), may not be indiscriminate (Schmitt, Reference Schmitt2017, Rule 105), and may not cause excessive “collateral damage” (Schmitt, Reference Schmitt2017, Rule 113). Tallinn 2.0 expressly acknowledges that when such IHL rules are violated, “[c]yber operations may amount to war crimes and thus give rise to individual criminal responsibility under international law” (Schmitt, Reference Schmitt2017, Rule 84).

Under the Rome Statute, “[the] Court shall have jurisdiction in respect of war crimes in particular when committed as a part of a plan or policy or as part of a large-scale commission of such crimes” (Rome Statute, 1998, Art. 8(1)). Additionally, all of the contextual elements for war crimes would need to be proven – such as the existence of an “armed conflict” (whether international or noninternational), a “nexus” between the cyberattack and the armed conflict (ICC, “Elements of Crimes,” 2011), and that the perpetrator was aware of the factual circumstances that established the existence of the armed conflict (ICC, “Elements of Crimes,” 2011). There would also be the elements for the specific underlying war crime(s), as well as – as explained above – the need to prove attribution (linking a specific perpetrator), intent, and jurisdiction. As to specific war crimes, note that the Rome Statute contains different lists of war crimes depending on whether the crimes were committed during international armed conflict or noninternational armed conflict (compare Rome Statute, 1998, Art. 8.2(a)–(b) with Art. 8.2(c), (e)).

As to the requirement of armed conflict, under the generally accepted definition from the ICTY’s Tadić case, “an armed conflict exists whenever there is a resort to armed force between States or protracted armed violence between governmental authorities and organized armed groups or between such groups within a State” (Prosecutor v. Tadić, 1995, para. 70). The Rome Statute (and IHL) particularly exclude “situations of internal disturbances and tensions, such as riots, isolated and sporadic acts of violence or other acts of a similar nature” (Rome Statute, 1998, Art. 8(2)(d)). An international armed conflict is one in which two or more states are parties to the conflict (Rona, Reference Rona2003, p. 58; Common Article 2 to the 1949 Geneva Conventions). Noninternational armed conflict is defined as “armed conflict not of an international character” (Common Article 3 to the 1949 Geneva Conventions). For noninternational armed conflict, the operations must also have reached a minimum level of intensity and a nonstate armed group must have achieved a certain level of organization (Prosecutor v. Tadić, 1995, para. 70).Footnote ¹³

The cyberattacks on Eastern Ukraine provide a possible example of war crimes perpetrated using, at least partly, cyberattacks. The attacks there were “blended attacks,” perpetrated through cyber and physical/kinetic means. In addition to the armed conflict that killed more than 10,000, the hacking into dozens of governmental organizations and companies through a “scorched-earth” cyberattack, which penetrated victims ranging from media outlets to railway firms and hospitals, caused hundreds of thousands of homes to lose electricity and shut down at least three regional utilities (Greenberg, Reference Greenberg2018; Bezhan, Reference Bezhan2016; Efrony & Shany, Reference Efrony and Shany2018, pp. 624–626). Both the United States and the United Kingdom believe that the cyberattacks on Ukraine were perpetrated by Russia’s military intelligence service, commonly known by the Russian acronym GRU (Warrell et al., Reference Warrell, Seddon and Manson2020).

The cyberattack, conducted during a state of armed conflict could, if all the elements of the crimes were able to be proved through admissible evidence, potentially constitute the war crime of intentionally directing attacks against the civilian population (Rome Statute, 1998, Art. 8(2)(b)(i)), or civilian objects (Rome Statute, 1998, Art. 8(2)(b)(ii)),Footnote ¹⁴ or inflicting “collateral damage” – incidental loss of life or injury to civilians that is “clearly excessive in relationship to the concrete and direct overall military advantage anticipated” (Rome Statute, 1998, Art. 8(2)(b)(iv)).Footnote ¹⁵ The cyber operations also appear to have been “indiscriminate.”Footnote ¹⁶ A cyberattack against a medical facility – of which there were several in Eastern Ukraine (Greenberg, Reference Greenberg2018) – could also constitute a war crime under Rome Statute Articles 8(2)(b) (xxiv) and (e)(ii) (Mačák et al., Reference Mačák, Gisel and Rodenhäuser2020). As with all ICC crimes, one would, among other things, additionally need to attribute responsibility to particular individuals for an ICC case to proceed and satisfy the intent requirement, both of which could prove difficult. There is ICC jurisdiction over the events in Ukraine because Ukraine executed an Article 12(3) declaration, accepting the ICC’s jurisdiction over crimes committed on its territory from November 21, 2013 to February 22, 2014, and then executed another such declaration covering crimes committed from February 22, 2014 and continuing on an open ended basis. (ICC Investigation, Ukraine, n.d.). Thus, there currently is ICC jurisdiction over cyberattacks that have been and are being committed in Ukraine, as well as jurisdiction over war crimes, crimes against humanity, and genocide more generally.

9 Cyberattacks as Crimes Against Humanity under the Rome Statute

Crimes against humanity are defined in the Rome Statute as acts “committed as part of a widespread or systematic attack directed against any civilian population, with knowledge of the attack” (Rome Statute, 1998, Art. 7(1)). The “attack” against the civilian population is defined as “a course of conduct involving the multiple commission of acts [enumerated in Article 7(1)] against any civilian population, pursuant to or in furtherance of a State or organizational policy to commit such attack” (Rome Statute, 1998, Art. 7(2)(a)).Footnote ¹⁷ For crimes against humanity, the attack is directed against a civilian population and need not be a military attack or linked to armed conflict (see, e.g., Prosecutor v. Ntaganda, 2019, para. 662). There are also requirements that the perpetrator’s “conduct was committed as part of a widespread or systematic attack directed against a civilian population” (the “nexus” requirement) and that “[t]he perpetrator knew that the conduct was part of or intended the conduct to be part of a widespread or systematic attack directed against a civilian population” (ICC, “Elements of Crimes,” 2011). The “underlying crimes” that support a charge (or multiple charges) of crimes against humanity are murder, extermination, enslavement, deportation, imprisonment, torture, rape or sexual violence, persecution, enforced disappearances, apartheid, and other inhumane acts (see Rome Statute, 1998, Art. 7(1)(a)–(k) for details).

Let us assume a “cyber-9/11” scenario, where the attackers have used cyber means to jam the controls of several airplanes, causing them to crash into buildings with ensuing large-scale loss of life. That would likely constitute the crime against humanity of murder if evidence proves that the attack was “widespread” (e.g., impacting a large number of victims) or “systematic” (a coordinated, organized attack) and orchestrated through a “State or organizational policy” (proof of which may be inferred, Prosecutor v. Bemba, 2016, para. 160), and one can attribute responsibility to particular perpetrators, prove intent, and satisfy jurisdictional requirements. The same cyberattack, if directed toward members of a particular protected group, could additionally constitute the crime against humanity of persecution (see Rome Statute, 1998, Art. 7(1)(h), listing protected groups). Crimes against humanity also include a residual “catch-all” – namely, “[o]ther inhumane acts of a similar character [to other crimes against humanity] intentionally causing great suffering, or serious injury to body or to mental or physical health” (Rome Statute, 1998, Art. 7(1)(k). Cyberattacks with severe consequences, such as a cyber 9/11, could also fall within this category.

While there appears to be great interest and concern about the problem of cyberattacks disrupting elections, to this author such interference – which could certainly be “widespread” and “systematic” (although it need not be both) – does not rise to the level of “other inhumane acts” because it would not involve “great suffering, or serious injury to body or to mental or physical health.” It also does not appear to fit into any of the other “underlying crimes” of crimes against humanity (see Rome Statute, 1998, Art. 7(1)(a)–(k)).Footnote ¹⁸

10 Cyberattacks as Genocide under the Rome Statute

Genocide is a crime that targets members of a distinct “national, ethnical, racial or religious group” (Rome Statute, 1998, Art. 6). For this crime, it is not the attack itself, but the intent behind the attack that is key. The dolus specialis (special mental state requirement) of genocide requires proof of: (1) “intent to destroy”; (2) “in whole or in part”; (3) of a “national ethnical, racial or religious group”; and (4) “as such” (i.e., because individuals belong to such a group) (ibid.; Kreβ, Reference Kreβ2006, p. 498). While genocide includes “inchoate” forms – for example, incitement to commit genocide could be the completed crime (Rome Statute, 1998, Art. 25(3)(e); Ohlin, Reference Ohlin2009, discussing “inchoate crimes”) – for Rome Statute purposes, if no genocide occurs the crimes probably would not satisfy ICC gravity requirements.

In addition to these overall requirements, there must be “underlying crimes”; the first enumerated being the killing of members of a group (Rome Statute, 1998, Art. 6(a)). The second underlying crime is “[c]ausing serious bodily or mental harm to members of the group” (Rome Statute, 1998, Art. 6(b)). The third underlying crime is “[d]eliberately inflicting on the group conditions of life calculated to bring about its physical destruction in whole or in part” (Rome Statute, 1998, Art. 6(c)) – see also Arts. 6(d)–(e)). Again, all are subject to Rome Statute gravity requirements, as one can also imagine a “mental” harm caused by a cyberattack that does not rise to the level of Rome Statute gravity, or creating horrible conditions of life for members of a protected group that is not necessarily aimed at bringing about the group’s physical destruction, and/or does not meet Rome Statute gravity. Thus, for a cyberattack to constitute the crime of genocide, it would need to satisfy both this overall special mental state requirement and proof of at least one of the underlying crimes. Additionally, as with all Rome Statute crimes, proof of attribution to particular individuals, proof of intent, and jurisdiction are required.

Here, it may be easier to envision cyber enabled genocide. In Rwanda, in 1994, Radio Télévision Libre des Mille Collines (RTLM) was used to incite and facilitate the killing of members of the Tutsi ethnic group – with the Tutsi identified by their government – issued identity cards, particularly at roadblocks (Metzi, Reference Metzi1997). One can similarly imagine cyber means used to compromise hospital or other medical records to identify members of a protected group, and/or; cyber means being used to incite genocide against protected group members (see, e.g., Mozur, Reference Mozur2018, discussing Burmese military Facebook incitement, coupled with crimes against the Rohingya). In either situation, assume the identification of protected group members and/or incitement is followed by killings (as it was in Rwanda and Myanmar), and one could infer the required genocidal intent (see, e.g., Prosecutor v. Akayesu, 1998); Burmese Military Document entitled “Rohingya Extermination Plan,” Mansour, Reference Mansour2017). Either could satisfy the elements of genocide.Footnote ¹⁹ Roscini also provides the example of a cyberattack that shuts down the cooling system of a nuclear power reactor releasing high levels of radiation killing members of a particular national group, if one could prove genocidal intent (Roscini, Reference Roscini2019, p. 250).

11 Cyberattacks as the Crime of Aggression under the Rome Statute

While the crime of aggression has numerous requirements and warrants a far more extensive discussion (see Trahan, forthcoming), some of the key requirements are that there is a state “act of aggression” (Rome Statute, 1998, Art. 8bis, para. 2) that, to qualify as the crime of aggression, must also constitute a “manifest” violationFootnote ²⁰ of the UN Charter by its “character, gravity and scale” (Rome Statute, 1998, Art. 8bis, para. 1). The “act of aggression” is defined as “use of armed force by a State against the sovereignty, territorial integrity or political independence of another State, or in any other manner inconsistent with the Charter of the United Nations”Footnote ²¹ (Rome Statute, 1998, Art. 8bis, para. 2). There is also a list of acts enumerated in Rome Statute Article 8bis, paragraph 2 (a)–(g) that could meet that requirement, but each would additionally need to constitute a “manifest” violation of the UN Charter (Rome Statute, 1998, Art. 8bis, para. 2 (a)–(g)).Footnote ²² Another requirement is that the crime only covers “leaders” in that it applies only to “person[s] in a position effectively to exercise control over or to direct the political or military actions of a State”Footnote ²³ (Rome Statute, 1998, Art. 8bis, para. 1). Also, the leader would need to engage in the “planning, preparation, initiation or execution” of the crime (Rome Statute, 1998, Art. 8bis, para. 1).

While the above requirements appear difficult to satisfy, the fourth act enumerated as potentially qualifying as an “act of aggression” is “[a]n attack by the armed forces of a State on the land, sea or air forces, or marine and air fleets of another State” (Rome Statute, 1998, Art. 8bis, para. 2(d)) and Article 8bis refers to “the use of any weapon by a State against the territory of another State” (Rome Statute, 1998, Art. 8bis, para. 2(b) (emphasis added)). Imagine a cyber unit within the armed forces of a state causes weapon systems of the armed forces of another state to become completely inoperable.Footnote ²⁴ That would constitute an “attack by the armed forces of a State” on the forces of another state. One would additionally need to attribute responsibility to a particular state leader (or head of cyber command) of the attacking armed forces who is “in a position effectively to exercise control over or to direct the political or military actions of a State,” and who planned, prepared, initiated, or played a role in the execution of the cyberattack. Changing the scenario slightly, imagine the leader or head of cyber command instead employs bands of nonstate hackers to conduct the same attack and later acknowledges those acts as acts of the state. Here one would look to the rules on state attribution to determine whether the acts of the nonstate actors become attributable to the state, with perhaps the clearest situation being where the hackers are hired into the state cyber command structure, so they become part of the armed forces.Footnote ²⁵ In any event, the cyberattack would need to be “manifest,” such that it is not de minimis (insufficient in gravity and/or scale) and/or “super clear” in terms of its illegality (meeting the required “character”). Yet, because of seemingly extensive jurisdictional limitations – if they are valid (see Trahan, Reference Trahan2018) – it could be quite difficult to trigger ICC jurisdiction regarding the crime of aggression, absent a UN Security Council referral.Footnote ²⁶

Returning to the example of election interference, this author doubts that the elements of the crime of aggression would be satisfied. While election interference could be viewed as a “sovereignty violation” (Shackelford, Reference Shackelford2017, 11; Efrony & Shany, Reference Efrony and Shany2018, 640), this author does not see it rising to the level of a “manifest” Charter violation, which is required for the crime of aggression (Rome Statute, 1998, Art. 8bis, para. 1). Furthermore, at least one significant state involved in election interference, the Russian Federation (Ohlin, Reference Ohlin2020), is not a party to the Rome Statute, so there would be no ICC jurisdiction over the crime of aggression committed by Russian nationals (ibid., Art. 15bis, para. 5).Footnote ²⁷

12 Conclusion

This chapter has briefly touched on what will need to be a far more extensive study considering how the crimes in the ICC’s Rome Statute could potentially encompass certain cyberattacks. Yet, hopefully, this chapter has made the case that there is at least some potential for applicability. My forthcoming article and the forthcoming report of the Council of Advisers on the Application of the Rome Statute to Cyberwarfare will expand significantly on these topics.

It is important to engage in this analysis, as there would need to be broad recognition of the ICC’s ability to prosecute certain cyberattacks if there is to be any potential for deterrence. Only then can international criminal law in this area play a role in maximizing the potential of reaching a state of cyber peace. It is actually quite significant that there is an existing international criminal tribunal with jurisdiction to prosecute a limited subset of cyberattacks. This capacity was probably never envisioned when the Rome Statute was negotiated; yet, certain cyberattacks appear to meet the elements of the ICC crimes. Whether it is feasible to bring cases will depend if attribution can also be established, and if all of the elements of the crime can be proven through admissible evidence that satisfies the standard, at trial, of proof beyond a reasonable doubt. Perhaps this is not fully feasible now, but as technology develops, it could become more achievable in the future.

None of the cyberattacks perpetrated to date probably have reached the threshold for Rome Statute crimes with the possible exception of those in Ukraine, over which the ICC has an open preliminary examination (ICC, “Preliminary Examination, Ukraine,” n.d.). It may also take time for the ICC to develop the required expertise to be able to develop and prosecute such cases, and the ICC may need to rely extensively on the outside expertise of cyber experts. Yet, as mentioned, that also carries potential pitfalls. To the extent the ICC can develop its own internal capacity that could help alleviate potential conflicts of interest.

International criminal law does have a role to play here. Will this deter all cyberattackers from committing grievous cyberattacks? The author will not be so naïve to claim that it will. But if the ICC is able to achieve some deterrence – deterring even one horrific cyberattack – that would certainly be a worthwhile endeavor. Ironically, it will be hard to know if such an attack has been deterred, because it would involve the absence of the attack, something notoriously difficult to prove.

While ICC States Parties may be “willing” and “able” to prosecute cyberattacks, and under Article 17 of the Rome Statute, that would then render a case “inadmissible” before the ICC (see Rome Statute, 1998, Art. 17), it is also quite possible that domestic jurisdictions will lack the required laws and/or be unable to exercise jurisdiction over the totality of the crime (which potentially might involve a foreign attacker state and multiple “victim” states). Then, the domestic jurisdiction would be “unable” to prosecute the case fully, likely rendering the case “admissible” before the ICC if other Rome Statute requirements are also satisfied.

To date, most of the ICC’s focus has been on crimes in developing countries. Because both developed and developing countries suffer from cyberattacks (probably developed countries even more so), a focus on such crimes before the ICC could be a welcome development, at least in the eyes of many ICC States Parties. Promoting the applicability of the Rome Statute to certain cyberattacks could additionally demonstrate an increased relevance of the ICC to one of the more vexing contemporaneous challenges facing the international community.