Machine identities are non-human identities used by systems, services, APIs, bots, and automated workloads to authenticate. They may be represented by certificates, service accounts, tokens, keys, or managed identities in cloud platforms. Unlike human logins, they are designed for software-to-software trust.
They matter because modern infrastructure depends on them for routine actions such as accessing databases, calling internal services, or moving data between cloud tools. If a machine identity is forged, overprivileged, expired, or left unmonitored, attackers can abuse it to blend in with legitimate automation. Defenders therefore treat machine identities as part of the attack surface: they restrict permissions, rotate credentials, track ownership, monitor unusual use, and revoke identities that are no longer needed. Strong lifecycle management helps prevent fake or stale identities from becoming trusted entry points.