According to the Department of Defense (DoD), a breach of personal information occurs when the information is lost, disclosed to, accessed by, or potentially exposed to unauthorized individuals, or compromised in a way where the subjects of the information are negatively affected. 1  Full DoD breach definition.ccording to the Department of Defense (DoD), a breach of personal information occurs when the information is lost, disclosed to, accessed by, or potentially exposed to unauthorized individuals, or compromised in a way where the subjects of the information are negatively affected. 1  Full DoD breach definition.