Closes a gap exposed by the comms safety audit: the existing
EMAIL_REDIRECT_TO env var only redirected outbound SMTP via the
sendEmail() bottleneck. Two channels still leaked when set:
1. Documenso e-signature recipients — Documenso's own server emails
them on our behalf, so SMTP redirect doesn't help. We were sending
real client emails to the Documenso REST API, which would then
deliver to the real client.
2. Outbound webhooks — fire from the BullMQ worker to user-configured
URLs. SSRF guard blocks internal hosts but doesn't pause production
endpoints.
Documenso (src/lib/services/documenso-client.ts):
- createDocument: rewrite every recipient.email to EMAIL_REDIRECT_TO
and prefix the recipient.name with the original email so the doc
is traceable.
- generateDocumentFromTemplate: same treatment for both v1.13
formValues.*Email keys and v2.x recipients[]. The redirect happens
BEFORE the API call, so even Documenso's own retry logic can't
reach the original recipient.
- Both paths log when they redirect so it's visible in dev.
Webhooks (src/lib/queue/workers/webhooks.ts):
- When EMAIL_REDIRECT_TO is set, short-circuit the dispatch and write
a `dead_letter` row with reason "Skipped: EMAIL_REDIRECT_TO is set,
outbound comms paused." so the attempt is still visible in the
deliveries listing.
Doc:
docs/operations/outbound-comms-safety.md catalogs every outbound
comms channel (email, Documenso, webhooks, WhatsApp/phone deep-links,
SMS-not-implemented) and explains how each one respects the env flag.
Includes a verification checklist to run before any production data
import + cutover steps for going live.
Single env var EMAIL_REDIRECT_TO now reliably pauses ALL automated
outbound comms. Unset for production.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Three findings from a fourth-pass review:
1. MEDIUM — webhook URL SSRF. The validator only enforced HTTPS+URL
parse; it accepted private/loopback/link-local/.internal hosts. The
delivery worker fetched arbitrary URLs and persisted up to 1KB of
response body into webhook_deliveries.response_body, which is then
surfaced via the deliveries listing endpoint — a port admin could
register a webhook to an internal HTTPS endpoint, hit the test
endpoint to force immediate dispatch, and read the response back.
Validator now rejects RFC-1918/loopback/link-local/CGNAT/ULA IPs
(v4 + v6) and .internal/.local/.localhost/.lan/.intranet/.corp
suffixes; the worker re-resolves the hostname at dispatch time and
blocks before fetch (DNS rebinding defense). 21-case unit test
covers the matrix.
2. MEDIUM — POST /api/v1/email/accounts/[id]/sync had no owner check.
Any user with email:view could enqueue an inbox-sync job for any
accountId, which the worker would honour using the foreign user's
decrypted IMAP credentials and advance the account's lastSyncAt
(data-loss risk on the legitimate owner's next sync). Route now
asserts account.userId === ctx.userId before enqueueing, matching
the toggle/disconnect endpoints.
3. MEDIUM — addDocumentWatcher (and the wizard / upload watcher
inserts) didn't validate the watcher's userId belonged to the
document's port. notifyDocumentEvent then emitted a real-time
socket toast + email containing the document title to the foreign
user. New assertWatchersInPort helper verifies each candidate has
a userPortRoles row for the port (super-admin bypass).
818 vitest tests pass.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
