A Directory Harvest Attack (DHA) is a technique used by spammers to find valid/existent email addresses at a domain either by using Brute force or by guessing valid e-mail addresses at a domain using different permutations of common username. Its easy for attackers to get hold of a valid email address if your organization uses standard format for official e-mail alias (for example: [email protected]). We can configure DHA Prevention to prevent malicious actors from quickly identifying valid recipients.
Note: Lightweight Directory Access Protocol (LDAP) is an Internet protocol that email programs use to look up contact information from a server, such as ClickMail Central Directory. For example, here's an LDAP search translated into plain English: "Search for all people located in Chicago who's name contains "Fred" that have an email address. Please return their full name, email, title, and description.