CERT warns that DNS Cache Poisoning attacks could be used also to hijack email to a rogue server. DNS is a critical component in a network because it is responsible for the translation of logical names into IP addresses. CERT/CC researchers have analyzed DNS responses belonging to Gmail, Yahoo! and Hotmail. The issue should be solved by DNSSEC, which guarantees the integrity of the DNS responses, which only around 0.5% of the.com and.net domains currently deploy DNSSec.”]
Source: https://securityaffairs.co/wordpress/28283/cyber-crime/dns-cache-poisoning-emails.html