Cyber operations can cause significant disruption. When a state fails to do what is arguably required to prevent, halt, mitigate or repress cyber operations, the nature of the relevant conduct is a potential failure to exercise due diligence, in other words, an omission. Illustrated with a case study on cyberspace, we aim to show that the attribution of omissions in the international law of state responsibility is far more straightforward than what states seem aware of. We conduct a comparative analysis of a set of reports submitted by states about how international law applies in cyberspace to examine how states deal with the attribution issues around failures to exercise due diligence. After more than twenty years of existence, the ILC Articles on State Responsibility are the uncontroversial reference point for the analysis of state responsibility and and examining them in relation to omissions underscores their practicality in addressing due diligence failures.