Det menes at WannaCry anvender den såkaldte EternalBlue exploit, der blev udviklet af det amerikanske [[National Security Agency]]<ref name="independent">{{Cite web|url=http://www.independent.co.uk/news/uk/home-news/nhs-cyber-attack-edward-snowden-accuses-nsa-not-preventing-ransomware-a7733941.html|title=NHS cyber attack: Edward Snowden says NSA should have prevented cyber attack|publisher=[[The Independent]]|access-date={{date|2017-05-13}}}}</ref><ref name="telegraph">{{Cite web|url=http://www.telegraph.co.uk/news/2017/05/13/nhs-cyber-attack-everything-need-know-biggest-ransomware-offensive/|title=NHS cyber attack: Everything you need to know about 'biggest ransomware' offensive in history|publisher=[[The Daily Telegraph]]|access-date={{date|2017-05-13}}}}</ref> for at kunne angribe computere, der kører [[Microsoft Windows]]-operativsystemerne.<ref>{{Cite web|url=http://money.cnn.com/2017/05/12/technology/ransomware-attack-nsa-microsoft/index.html|title=Massive ransomware attack hits 74 countries|last=Larson|first=Selena|date={{date|2017-05-12}}|access-date={{date|2017-05-12}}}}</ref> Selv om en rettelse der fjerner den underliggende svaghed blev udsendt 14. marts 2017, har forsinkelser i installationen af sikkerhedsopdateringerne betydet at nogle brugere og organisationer stadig var sårbare.<ref>{{Cite web|url=https://www.theregister.co.uk/2017/05/12/spain_ransomware_outbreak/|title=WanaCrypt ransomware snatches NSA exploit, fscks over Telefónica, other orgs in Spain|last=15:58|first={{date|2017-05-12}} at|access-date={{date|2017-05-12}}}}</ref> Microsoft har taget det usædvanlige skridt at udsende opdateringer til versioner af Windows, der ikke længere er officielt understøttet, som [[Microsoft Windows XP|Windows XP]] og [[Windows Server 2003]] samt opdateringer til [[Microsoft Windows 8|Windows 8]] operativsystemerne.<ref name="unsupported">{{Cite web|last=Surur|date={{date|2017-05-13}}|title=Microsoft release Wannacrypt patch for unsupported Windows XP, Windows 8 and Windows Server 2003|url=https://mspoweruser.com/microsoft-release-wannacrypt-patch-unsupported-windows-xp-windows-8-windows-server-2003/|access-date={{date|2017-05-13}}}}</ref>
Jura Juridiske_begreber Retsvidenskab Kriminalitet