Thanks everyone for your comments on this. I like this excerpt from doesmysiteneedhttps.com:
"this discussion isn't about PKI. It's the best system we've got for right now. Deal with it and secure your site. Use CAA records to restrict which CAs can issue certificates for your site, then cross your fingers and hope transparency and oversight works (it does, so far)".
Do you all feel that there is enough integrity in browser trusted root certificate stores to still provide robust defence against the content / malware injection threat?
Also - have these kinds of injection attacks ceased now, and is SSL the reason for this?
Thanks!