MSAL Android is Microsoft’s supported library for sign-in and token acquisition in Android apps. It implements OAuth 2.0 and OpenID Connect flows, helping apps authenticate users and obtain access tokens for Microsoft services. The library manages details such as redirect handling, broker integration, and token caching, so developers do not build those security-sensitive parts from scratch.
It matters because tokens are bearer credentials: if an attacker can intercept or reuse them, they may gain access without knowing a password. In real attacks, weakness usually comes from misconfiguration rather than the library itself, such as an incorrect redirect URI, exported component, or permissive development setting that lets another app on the device interfere with the auth flow. Defenders use MSAL’s recommended settings, PKCE, and strict package/signature checks to keep token responses bound to the right app and reduce interception risk.