OAuth authorization code theft via legacy SSO open redirect
- Asset
- sso-legacy.example-corp.com → billing.example-corp.com
- Impact
- Account takeover of any billing user who clicks a link; read access to 41,207 invoices proven via planted canary record.
- Detected?
- No. No alert in SIEM or EDR. Nightwatch rule BW-3192 drafted.
- Fix
- Exact-match
redirect_uri allowlist on IdP client 0x41; rotate client secret.
- 1Open redirect on /sso/continue accepts any https hostT+07m
- 2IdP allows wildcard redirect for legacy clientT+12m
- 3Code exchanged for session as svc-billingT+18m
- 4Canary invoice INV-CANARY-77 retrieved, chain haltedT+22m
$ rogue replay SEC-8812 --dry-run
✓ step 1 302 → https://callback.rogue-lab.net/c
✓ step 2 code=7f3c…a1 captured (redacted)
✓ step 3 session issued: role=billing_reader
✓ step 4 canary match · sha256 9e1b…04
replay deterministic · safe to run in CI