Snapchat: Subdomain takeover of blog.snapchat.com

Overview The ANAME for blog.snapchat.com, which redirects to snapchat-blog.com, was pointing to tumblr for Snapchat's blog. This blog had been expired or had removed the CNAME claim. Adding "snapchat-blog.com" to the custom domain setting on tumblr allowed takeover of this subdomain. Repro Steps ...