An OAuth token is a credential that authorizes an application to access specific data or actions on a user’s behalf without giving the app the user’s password. Tokens are issued after an approval step, often through a login and consent flow, and they usually carry limited scopes, such as read-only access or access to a single service.
In cyber security, OAuth tokens matter because they turn trust into access. If an attacker steals a token, tricks a user into approving a malicious connected app, or abuses a compromised integration, they may be able to query APIs, export records, or move through SaaS systems while appearing legitimate. Defenders reduce this risk by reviewing connected apps, limiting token scopes, enforcing short lifetimes and revocation, and monitoring API activity and unusual exports for signs of abuse.