[Screenhero] Subdomain takeover

Hi, I found out some neglected DNS records that can be exploited to takedown the subdomain of Slack's acquisition `feedback.screenhero.com` The security issue is that you have CNAME record that points `feedback.screenhero.com` to a `screenhero.uservoice.com`, but the problem is that the service is inactive, thus any malicious hacker would simply sign up for the service and claims the username `Screenhero` as his and no verification is done by the Service Provider, besides that the DNS-setup is already correctly set. {F97017} **Scenario attack :** Attacker can now build a complete clone of the real site, add a login form, redirect the user, steal credentials (e.g. admin accounts), cookies and/or completely destroy business credibility for your company along with along with injecting malicious codes to steal their sensitive cookies, redirect them to malicious web pages etc. **Mitigation :** To mitigate the threat you should remove CNAME DNS records for the services you don't use anymore. **Reference:** http://yassineaboukir.com/blog/neglected-dns-records-exploited-to-takeover-subdomains/ Best regards.