An XP computer is old, Windows 8.1 is one generation back. Both are vulnerable to this exploit. Yes, patches have been available for supported versions, I don't know how that makes anything I said wrong or misleading.
We agree about it being not JUST old Windows versions being affected.
I replied to your comment because the "old" Windows XP having no patch available was significant here, and I read your comment as saying "old" windows versions were not proportionally more responsible for WannaCry's rapid spread.
Windows XP is still the third largest version of Windows by current installed base (after Windows 10 and Windows 7).
The fact that Windows XP remained unpatched was significant, as there is notable overlap between Windows machines that aren't getting new security updates (at least within a month or two of their release) and Windows machines still running Windows XP.
This vulnerability was, in fact, unusually dangerous, relative to other Windows XP vulnerabilities that have come to light in the last 5 years, and the install base of the "older" Windows XP machines made a big difference in the ransomware's ability to spread.
The resources I see don't show XP as third, though I'm sceptical of anything based on user agent. And I can't find anything about how responsible they would be for the spread.
I addressed that it wasn't "old" Windows because there is a crazy belief out there that this only hit XP.
I replied to your comment because the "old" Windows XP having no patch available was significant here, and I read your comment as saying "old" windows versions were not proportionally more responsible for WannaCry's rapid spread.
Windows XP is still the third largest version of Windows by current installed base (after Windows 10 and Windows 7).
The fact that Windows XP remained unpatched was significant, as there is notable overlap between Windows machines that aren't getting new security updates (at least within a month or two of their release) and Windows machines still running Windows XP.
This vulnerability was, in fact, unusually dangerous, relative to other Windows XP vulnerabilities that have come to light in the last 5 years, and the install base of the "older" Windows XP machines made a big difference in the ransomware's ability to spread.