A merger combines two previously separate organizations into one. For information security, it also means bringing together different identities, networks, cloud environments, devices, policies, and security processes. The security condition of each organization therefore becomes relevant to the other, especially before systems or data are connected.
Security due diligence should identify exposed services, unsupported systems, active incidents, privileged accounts, contractual obligations, and privacy requirements before integration. Afterward, teams need an accurate asset inventory, controlled trust relationships, least-privilege access, coordinated vulnerability management, and compatible logging and incident-response procedures. Data sharing and retention must remain consistent with applicable law and existing commitments; access should not be broadened merely because the organizations now have common ownership.