Even though opportunistic encryption protects messages during transmission from sender to receiver, it is still possible for a Man-in-the-Middle (MITM) attacker with a self-signed certificate to impersonate the intended destination. This brief document describes the MITM situation, outlines various methods bad actors can use to conduct MITM attacks, covers components for deterring these attacks and introduces DANE (DNS-based Authentication of Named Entities), a new technology to assist messaging providers in validating they are communicating with an intended destination when using SSL/TLS.

Written in plain language by M3AAWG and the London Action Plan (LAP), Operation Safety-Net outlines the current and emerging threats faced by consumers, businesses and governments with recommended best practices to address these threats. For a brief overview of the document, see the brochure explaining the global depth and breadth of these best practices in the Supporting Documents section from the For the Industry menu tab.