fix(backend): reject a replayed TOTP code within its validity window (#1389)

* fix(backend): reject a replayed TOTP code within its validity window verifyTotp() was stateless — otplib's window:1 tolerance meant the same 6-digit code could complete two independent logins inside its ~90s validity window. Track each admin's last-consumed step and reject a code that doesn't advance past it. * fix(backend): make the TOTP replay-tracking persist atomic verifyTotpEncryptedStep() read two_factor_last_used_step, then a plain UPDATE wrote the new step with no conditional guard — two concurrent requests carrying the same captured code could both pass the check before either UPDATE landed. The persist is now a conditional UPDATE (only advances the step, checked via affected-row count), so a losing concurrent request is correctly treated as a replay. --------- Co-authored-by: Paul Nothaft <[email protected]>
2026-09-11 10:40:27 +02:00
parent e3247911a0
commit cdde937d7f
7 changed files with 426 additions and 13 deletions
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+/**
+ * Migration 213: TOTP replay protection for admin MFA (GHSA-qcwx-r25m-j869).
+ *
+ * verifyTotp()/verifyTotpEncrypted() were stateless: otplib's window:1
+ * tolerance means a captured 6-digit code stays valid across several real
+ * time-steps (~90s), so the same code could complete two independent admin
+ * logins. `two_factor_last_used_step` tracks, per admin, the absolute TOTP
+ * time-step (Math.floor(Date.now() / 30000)) that their last successfully
+ * consumed code matched; mfaService now rejects a code whose matched step
+ * doesn't advance past it.
+ *
+ * Additive and idempotent: only adds a column, guarded by hasColumn, so it
+ * is safe to re-run and touches no existing data.
+ */
+exports.up = async function (knex) {
+  if (!(await knex.schema.hasColumn('admin_users', 'two_factor_last_used_step'))) {
+    await knex.schema.alterTable('admin_users', (t) => {
+      t.integer('two_factor_last_used_step').nullable();
+    });
+  }
+};
+
+exports.down = async function (knex) {
+  if (await knex.schema.hasColumn('admin_users', 'two_factor_last_used_step')) {
+    await knex.schema.alterTable('admin_users', (t) => {
+      t.dropColumn('two_factor_last_used_step');
+    });
+  }
+};