The <a href="https://en.wikipedia.org/wiki/WannaCry_ransomware_attack" id="mwAXk" rel="mw:WikiLink" title="WannaCry ransomware attack">WannaCry ransomware attack</a> impacts over 400,000 computers worldwide, targeting computers of the United Kingdom's <a class="mw-redirect" href="https://en.wikipedia.org/wiki/National_Health_Services" id="mwAXo" rel="mw:WikiLink" title="National Health Services">National Health Services</a> and <a href="https://en.wikipedia.org/wiki/Telefónica" id="mwAXs" rel="mw:WikiLink" title="Telefónica">Telefónica</a> computers.<sup about="#mwt105" class="mw-ref reference" data-mw='{"name":"ref","attrs":{},"body":{"id":"mw-reference-text-cite_note-19"}}' id="cite_ref-19" rel="dc:references" typeof="mw:Extension/ref"><a href="./May_12#cite_note-19" id="mwAXw" style="counter-reset: mw-Ref 19;"><span class="mw-reflink-text" id="mwAX0">[19]</span></a></sup>
<span class="mw-reference-text" id="mw-reference-text-cite_note-19"><cite about="#mwt102" class="citation web cs1" id="mwBjY"><a class="external text" href="https://www.theguardian.com/technology/2017/may/12/nhs-ransomware-cyber-attack-what-is-wanacrypt0r-20" id="mwBjc" rel="mw:ExtLink nofollow">"What is WannaCry ransomware and why is it attacking global computers?"</a>. <i id="mwBjg">The Guardian</i>. May 12, 2017<span class="reference-accessdate" id="mwBjk">. Retrieved <span class="nowrap" id="mwBjo">September 20,</span> 2021</span>.</cite><span about="#mwt102" class="Z3988" id="mwBjs" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=unknown&amp;rft.jtitle=The+Guardian&amp;rft.atitle=What+is+WannaCry+ransomware+and+why+is+it+attacking+global+computers%3F&amp;rft.date=2017-05-12&amp;rft_id=https%3A%2F%2Fwww.theguardian.com%2Ftechnology%2F2017%2Fmay%2F12%2Fnhs-ransomware-cyber-attack-what-is-wanacrypt0r-20&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3AMay+12"></span></span>