An LOA, or letter of authorization, is a document showing that a person or organization has permission to act on an account. It may authorize account changes, access, or administrative work, and commonly identifies the account holder, the authorized party, and the scope of permission.
In cyber security, an LOA can be sensitive because it may help someone establish authority over a client account or service. Attackers who obtain genuine authorization documents could use them in social engineering or account takeover attempts; forged documents can also be used to deceive support staff. Organizations should store LOAs securely, verify them through trusted channels, and check that each document is current and limited to the necessary permissions.