The only throttle on POST /api/auth/login was the per-IP limiter in server.js. That
bounds one noisy source and nothing else: it does not bound a distributed attempt, and
it is only as accurate as a deployment's proxy configuration. Nothing counted failures
against the account actually being attacked, and nothing cleared such a count on success
because no such count existed.
lib/login-lockout.js mirrors lib/totp-lockout.js and lib/pair-lockout.js so there is one
lockout idiom here rather than three. 10 failed passwords lock an account for 15 minutes.
Keyed on user.id, never on the submitted email: the email is attacker-supplied and
unbounded, so keying on it would let anyone grow the Map without limit — the same class
of bug fixed elsewhere in this campaign. A user id only exists for a real account, so the
key space is bounded by the user table and needs no eviction sweep, exactly like
totp-lockout.
A locked account returns the SAME 401 and body as a wrong password. A distinct 429 would
tell an attacker "this account exists and is under attack", turning login into an
account-existence oracle; the test asserts the locked response is byte-identical to both
the wrong-password and unknown-account responses. The trade is that a locked-out
legitimate user sees the generic message, so the trip is recorded in activity_log
(auth:login_locked) for the operator instead.
The counter is cleared as soon as the password verifies — before the TOTP and
email-verification branches, which return early and never reach issueSession, so a reset
placed there would never fire for those accounts. SSO paths do not share this code and
are unaffected.
Frontend needs no change: login.js renders any non-ok body's `error` string verbatim, and
the body is unchanged.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
