Scenario 06: Cyber countermeasures against an enabling State

A country believed to possess highly developed cyber capabilities repeatedly fails to assist other States in countering cyber attacks emanating from its territory. After yet another malicious cyber operation from the former State’s territory results in numerous casualties abroad, the said State comes under a large-scale DDoS attack. The scenario considers the international obligation of due diligence in the cyber context and the ability of States to take countermeasures in response to violations of that obligation.

Keywords
Countermeasures, critical infrastructure, DDoS, due diligence, international co-operation, non-State actors

Facts
[F1] State A is generally considered to possess advanced cyber capabilities, including detection and incident reaction capabilities. However, it has come under a growing criticism that it does not do enough to thwart malicious cyber activities that originate from or transit through its territory. Several States have made public statements in international fora complaining that their requests for assistance submitted to State A’s authorities had been ignored. Nonetheless, State A’s public response has been to maintain that it had attended to all reasonable requests received from other States.

[F2] Following an aircraft crash in State B involving scores of casualties, caused apparently by a fault in the air traffic control system of State B’s receiving airport, its domestic forensic investigation concludes that the fault had been caused by a premeditated cyber operation originating from the territory of State A and that it cannot be excluded that the operation will be repeated. State B’s relevant authorities submit a request for an urgent assistance to State A, asking that more information be provided on specific actors and that the infrastructure identified in the request be investigated and command and control servers shut down immediately.

[F3] Several days later, the foreign ministry of State B issues a statement claiming that no response has been received from State A to the request for assistance. The statement further says that it considers the matter to be one of utmost importance for its national security and expresses grave concerns about impact on mutual relations. On the same day, the foreign ministry of State A responds with a public statement noting that while it cannot comment on any ongoing investigation, its general policy is to attend to all reasonable requests for assistance received from other States. It adds that in any event its domestic laws do not allow it to intervene in privately owned cyber infrastructure.

[F4] One week after this exchange of statements, hundreds of State A’s government servers come under sustained large-scale distributed denial-of-service (DDoS) attacks. As a result, many public services ordinarily provided to the population of State A by online means become unavailable, including the system of e-health prescriptions, lodging of e-tax returns, and e-ticketing on public transport across the country.

Examples

 * Colonial Pipeline ransomware attack (2021)
 * Springhill Medical Center ransomware attack (2019)
 * DNC email leak (2016)
 * Office of Personnel Management data breach (2015)
 * Sony Pictures Entertainment attack (2014)
 * Cyber attacks against Estonia (2007)

Legal analysis
For a general overview of the structure of analysis in this section, see Note on the structure of articles.

[L1] The legal analysis in this scenario first considers whether State A’s failure to respond to State B’s request for assistance qualifies as a violation of its due diligence obligations under customary international law or any specific treaty obligations related to interference with air traffic control. It then examines whether the measures State B took in response can be qualified as lawful countermeasures against State A.

Due diligence
[L2] In the present scenario, all the elements seem to have been met. To begin with, the cyber operation against State B has resulted in the deaths of many individuals and significant destruction in that State’s territory. As such, the operation was manifestly contrary to the rights of State B (condition 1).

[L3] The indicators of compromise identified by the authorities of State B suggest that cyber infrastructure on the territory of State A had been used to mount the cyber operation in question. This information has not been opposed in any way by the territorial State. The acts in question should thus be seen as conducted from or at least through the territory of State A (condition 2).

[L4] Air traffic control systems usually form part of a State’s critical infrastructure and their proper functioning can be considered as pertaining to national security as well as part of that State’s international obligations in case of international aerial transportation. There is no doubt that a cyber operation which disables air traffic control systems, prevents the State from fulfilling its international obligations, and may result in lethal effects, thus impacting on national security, constitutes a breach of international law. Therefore, had the acts and omissions in question been attributed to State A, they would manifestly have been internationally unlawful (condition 3).

[L5] Similarly, there is little doubt that an operation that results in scores of civilian deaths should be seen as entailing “serious adverse consequences” for the victim State. This criterion may be somewhat difficult to meet with respect to certain “below the threshold” operations. However, it is generally accepted that “operations that would comprise, were they to be directly undertaken by a State, ‘over the threshold’ of international law rules on use of force” do trigger the due diligence obligations of the potentially responsible State (condition 4).

[L6] The next question is one of knowledge. It is unclear whether State A had actual knowledge of the forthcoming hostile operation from its territory in the first place. However, there are strong indications that it had at least constructive knowledge of the operation. In particular, its possession of advanced detection capabilities combined with its ignorance of repeated States’ requests for assistance suggest that State A should have known of the operation in question or that it had turned a blind eye to it. Hypothetically, if the attackers had used, at least in part, State A’s governmental cyber infrastructure, it would be easier to claim State A’s knowledge. Nonetheless, by the time State B’s relevant authorities had submitted the request for assistance to State A, the knowledge element (condition 5) would likely have been met. [L7] Finally, it appears that State A has failed to take any measures to stop the hostile operation emanating from its territory. It may well be the case that State A’s domestic law proscribed it from acting against the threat, as its foreign ministry implied when it noted that State A’s authorities may not intervene in privately owned cyber infrastructure. However, this would be of no relevance as to the characterization of State A’s conduct under international law, given that “domestic legal limitations do not justify a State’s failure to comply with its due diligence obligation”. Similarly, State A would not be assisted by a reference to its general policy to respond to other States’ requests. In this regard, the pattern of ignoring requests apparent from prior public statements by other countries would amount to an indication that this policy is actually ineffective in practice. In sum, State A’s failure to take any specific steps designed to put an end to the hostile operations against State B strongly suggests that it had failed to act in response to the acts contrary to the rights of State B (condition 6). [L8] In addition to these general considerations relating to the obligation of due diligence which applies as a matter of customary international law, specific States may have additional treaty obligations in similar situations of interference with air traffic control. This is particularly the case with respect to those States that are parties to the 1971 Montreal Convention. The Convention prescribes that a State which has “reason to believe” that an offence of this kind will be committed, has a duty to furnish any relevant information to the potential victim State. Moreover, once the offence has been committed, States have an obligation to “afford one another the greatest measure of assistance” in the resulting criminal proceedings. Accordingly, if States A and B both were parties to the Montreal Convention, then the failure of State A to warn and later to assist State B could additionally violate the former’s relevant treaty obligations.

Countermeasures in response to a violation of due diligence
[L9] Assuming that due diligence is a binding international legal obligation that extends to the cyber context (a question that is analysed in the section on due diligence), an injured State may respond to the violation of this obligation by resorting to countermeasures against the responsible State. Any such response must comply with the strict conditions that international law imposes on the lawful exercise of countermeasures.

[L10] In the present case, whether or not the relevant criteria have been met would depend on the following considerations. At the outset, it should be noted that the analysis proceeds on the assumption that the DDoS attacks against State A’s cyber infrastructure were attributable to State B. It is also assumed that the act of launching the attacks could qualify as a breach of an international obligation of State B (for the analysis of a similar fact pattern, refer to Scenario 05). Without these preconditions, any assessment of countermeasures would be moot as there would be no relevant conduct by the injured State in question that could potentially qualify as a countermeasure.

[L11] Firstly, State A’s violation of its due diligence obligations amounts to a prior internationally wrongful act against State B as the injured State. Additionally, State A’s failure to act qualifies as a continuing internationally wrongful act for as long as it chooses not to take any specific steps designed to put an end to the hostile operations against State B. This period of inaction by State A also delineates the temporary scope within which State B may, provided that the remaining conditions are met, resort to countermeasures.

[L12] Secondly, the public statement by State B’s foreign ministry may be construed as a request on State A to cease its internationally wrongful conduct. It has been noted that the requirement of notification is “probably unrealistic” in the cyber context, and it is the view of several States that prior notification need not be given if doing so would expose highly sensitive capabilities needed for national defence, or if it would adversely affect the effectiveness of the measures taken.

[L13] Thirdly, for the DDoS attacks against State A’s infrastructure to be lawful, their object should have to have been strictly limited to inducing State A to comply with its international obligations. In particular, if State A did indeed provide the requested information to State B while the attacks were underway, State B would have to terminate the attacks given that the object of its countermeasure — the restoration of legality as between the two States — would have been achieved. The aim to restore the legality on both sides implies that countermeasures should be, “as far as possible”, reversible in nature; this criterion is typically met by DDoS attacks such as those launched against State A in the present scenario.

[L14] Fourthly, the DDoS attacks against State A would have to comply with the requirement of proportionality. To begin with, proportionality does not imply that the injured State’s response must be equivalent, reciprocal, or in-kind. This is of crucial importance in the present case, as any active response to a failure to act will always by definition be non-reciprocal in nature. In favour of proportionality, State B could argue that its action was commensurate with the injury suffered, taking into account the severe risk of further loss of life and significant damage that may result if future hostile operations emanating from State A’s territory are not thwarted. By contrast, the impact of the DDoS attacks on services wholly unrelated to State A’s unwillingness to thwart malicious cyber operations would militate against the proportionality of the supposed countermeasures. Ultimately, the assessment of proportionality is highly contextual and would depend on the specific circumstances of the case at hand.

[L15] Finally, the DDoS attacks against State A do not prima facie violate the obligations that must not be affected by countermeasures under international law.

Checklist

 * Due diligence:
 * Did the relevant cyber operation adversely affect the rights of a State?
 * Was the cyber operation conducted from or through the territory of another State?
 * Would the cyber operation have been unlawful if conducted by the potentially responsible State?
 * Did the incident result in serious adverse consequences for the victim State?
 * Did the potentially responsible State know of the incident in question? Alternatively, even if it only became aware of the incident through the information from the injured State, should it have known of it at the material time?
 * Did the potentially responsible State take all feasible measures to put an end to the malicious cyber activities?
 * Countermeasures:
 * Is the injured State responding to a prior internationally wrongful act of the responsible State?
 * Would the injured State’s conduct taken in response amount to an internationally wrongful act if not justified as a countermeasure?
 * Do the measures taken in response by the injured State meet the conditions prescribed for the lawful resort to countermeasures under international law?

Bibliography and further reading

 * Luke Chircop, ‘A Due Diligence Standard of Attribution in Cyberspace’ (2018) 67 ICLQ.
 * James Crawford, State Responsibility: The General Part (CUP 2013).
 * Dan Efrony and Yuval Shany, 'A Rule Book on the Shelf? Tallinn Manual 2.0 on Cyberoperations and Subsequent State Practice' (2018) 112 AJIL.
 * Robin Geiss and Henning Lahmann, ‘Freedom and Security in Cyberspace: Shifting the Focus Away from Military Responses Towards Non-Forcible Countermeasures and Collective Threat-Prevention’ in Katharina Ziolkowski (ed), Peacetime Regime for State Activities in Cyberspace (NATO CCD COE 2013).
 * James Green, ‘Fluctuating Evidentiary Standards for Self-Defence in the International Court of Justice’ (2009) 58 ICLQ 163
 * Marco Roscini, Cyber Operations and the Use of Force in International Law (OUP 2014).
 * Michael N Schmitt (ed), Tallinn Manual 2.0 on the International Law Applicable to Cyber Operations (CUP 2017).
 * Rüdiger Wolfrum, ‘Obligation of Result Versus Obligation of Conduct: Some Thoughts About the Implementation of International Obligations’ in Mahnoush H Arsanjani and others, Looking to the Future: Essays on International Law in Honor of Michael Reisman (Brill 2010).

Contributions

 * Scenario by: Taťána Jančárková & Kubo Mačák
 * Analysis by: Kubo Mačák
 * Reviewed by: Václav Borovička; Dan Efrony; Anna-Maria Osula; Barrie Sander; Peter Stockburger