The worm reused the meterpreter code which didn't target XP at all. For some reason some people are having are hard time dealing with this: https://news.ycombinator.com/item?id=14377799 and I am beginning to wonder why. Any insights?
Small nitpick- though the worm aspect of WCry does have a lot of issues with targeting WinXP, the meterpreter part of that sentence is a widespread myth that originated from poor wording in a slide. Source, w/ a reply that has a link to correction from the original author: https://twitter.com/riskybusiness/status/864293475981729793