Session Management

Session management

A session is the credential a user carries after login, so a stolen or stale session is a stolen identity. The dangers are a token that never dies, one that survives a password change, and one exposed to script or sent in the clear. Good session handling is about controlling the token's lifetime and reach.

Method

1. Set the cookie flags that lock the token down. Mark session cookies HttpOnly (script cannot read them), Secure (HTTPS only), and SameSite=Lax or Strict (limits cross-site sending). Scope with Path and avoid a wildcard Domain. These four attributes block the cheapest theft routes.
2. Rotate the session ID on every privilege change. Issue a new identifier at login, at logout, and when a user elevates (assumes admin, re-authenticates for a sensitive action). Rotation defeats fixation and shrinks the window a captured pre-elevation token is worth anything.
3. Expire on both idle and absolute timeouts. Enforce an inactivity timeout (for example 30 minutes) and a hard maximum lifetime (8 to 24 hours) after which re-login is required regardless of activity. A token that lives forever is a permanent key once copied.
4. Store sessions server-side so you can revoke them. Keep a server record (a session store, Redis, a table) keyed by an opaque random ID, so logout, a password reset, or an admin action can delete it and end the session at once. If you use stateless JWTs, add a revocation list or keep lifetimes very short, because a plain JWT cannot be recalled.
5. Generate identifiers from a CSPRNG. Use at least 128 bits from a cryptographically secure source (secrets.token_urlsafe, crypto.randomBytes), not a counter, a timestamp, or Math.random. A guessable session ID is an open door that needs no theft.
6. Invalidate sessions on the events that demand it. On logout, delete the server record, do not just clear the cookie. On password change or reset, revoke that user's other sessions so a thief already inside is evicted.

Checks

• Do the response headers show HttpOnly, Secure, and SameSite on the session cookie?
• After a password reset, are the user's other active sessions rejected on their next request?
• Does an idle session stop working after the timeout, verified by waiting past it?

Boundaries

Session management picks up after authentication succeeds and hands off to authorization for per-request access decisions. It does not cover the login flow itself (see authn-design) or token-based API patterns like OAuth bearer tokens, whose lifecycle differs. Framework session middleware handles most of this correctly; the risk is in overrides and custom stores.