“[..]the obligation of all States to refrain from the threat or use of force against the territorial integrity or political independence of any State. A cyber operation can cause severe consequences and effects. In determining whether a cyber operation amounts to the use of force, factors that may be taken into account include, but are not limited to, the prevailing circumstances at the time of the cyber operation, the origin of the cyber operation, the effects caused or sought by the cyber operation, the degree of intrusion of the cyber operation, and the nature of the target.\n <\/p>\n

While Singapore considers the above principles to be essential ones underpinning the international legal order, Singapore\u2019s position is that it bears noting that ultimately, none of these impair a State\u2019s inherent right of self-defence, as provided under the UN Charter. This right of self-defence also applies in the cyber domain. In other words, a State has the inherent right of self-defence if malicious cyber activity amounting to an armed attack, or an imminent threat thereof, occurs against that State.\n <\/p>\n

Malicious cyber activity attributable to a State that causes death, injury, physical damage or destruction equivalent to a traditional non-cyber armed attack, or presenting an imminent threat thereof, would constitute an armed attack. Singapore notes the increasing prevalence of this view amongst States.\n <\/p>\n

In Singapore\u2019s view, it is also possible that, in certain limited circumstances, malicious cyber activity may amount to an armed attack even if it does not necessarily cause death, injury, physical damage or destruction, taking into account the scale and effects of the cyber activity. An example might be a targeted cyber operation causing sustained and long-term outage of Singapore\u2019s critical infrastructure.\n <\/p>\n

“Even if malicious cyber activity against a State has not risen to the level of an armed attack entitling the victim State to exercise the right of self-defence, international law provides that a victim State that is subjected to another State\u2019s internationally wrongful act against it (whether through malicious cyber activity, or physical means) is entitled to have recourse to counter-measures which are consistent with international law.\n <\/p>\n