Domain validated SSL certificates (DV SSL) are server security certificates that provide the lowest level of validation available from commercial certificate authorities.
Before a DV SSL certificate can be issued, the issuing certificate authority will verify that a contact at the domain in question approves the certificate request. This approval is usually done by email, but can also be done via telephone or through alternate methods.
Because DV certificate issuance can usually be automated, DV certificates are often offered at prices much lower than High-Assurance or EV SSL certificates, both of which require a degree of human element in the certificate issuance process and additional organizational validation processes.
While DV certificates verify the consent of a domain owner, they make no attempt to verify who the domain owner really is. The manner in which domain validation is carried out makes this kind of certificate ideal for both phishing and man in the middle attacks.