Security hardening: token validation and service URL improvements#370
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Pull request overview
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Security hardening for token validation and inbound serviceUrl handling, plus preventing DevTools from running in production.
Changes:
- Added
serviceUrldomain allowlist validation (withadditional_allowed_domains) and strengthened JWT scope checks to exact set membership. - Added issuer-validation warning when Entra validation is configured without a tenant ID.
- Added a production-environment guard to prevent the DevTools plugin from starting, with accompanying unit tests.
Reviewed changes
Copilot reviewed 10 out of 10 changed files in this pull request and generated 6 comments.
Show a summary per file
| File | Description |
|---|---|
| packages/devtools/src/microsoft_teams/devtools/devtools_plugin.py | Blocks DevTools plugin initialization when environment indicates production. |
| packages/devtools/tests/test_devtools_plugin.py | Adds tests for DevTools production guard and basic plugin initialization behavior. |
| packages/apps/src/microsoft_teams/apps/auth/token_validator.py | Adds service URL allowlist logic, warning for missing tenant ID, and exact scope matching. |
| packages/apps/src/microsoft_teams/apps/http/http_server.py | Adds serviceUrl allowlist validation and plumbs additional_allowed_domains into server init. |
| packages/apps/src/microsoft_teams/apps/options.py | Adds additional_allowed_domains to app options/internal options. |
| packages/apps/src/microsoft_teams/apps/app.py | Passes additional_allowed_domains from app options into server initialization. |
| packages/apps/tests/test_token_validator.py | Adds unit tests for domain allowlist, exact scope matching, and issuer warning. |
| packages/apps/tests/test_http_server.py | Adds unit tests for idempotent initialize, endpoint validation, auth rejection, and serviceUrl allowlist behavior. |
| packages/apps/tests/test_app.py | Adds unit test for merging app options with defaults. |
| examples/cards/src/main.py | Formatting-only change (single-line method chaining). |
lilyydu
reviewed
Apr 20, 2026
heyitsaamir
approved these changes
Apr 21, 2026
corinagum
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to microsoft/teams-sdk
that referenced
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Apr 22, 2026
## Summary Documentation for security hardening changes shipping in the SDK PRs: - microsoft/teams.ts#515 - microsoft/teams.py#370 - microsoft/teams.net#418 ### New page: Service URL Validation `src/pages/templates/essentials/service-url-validation.mdx` + per-language include files Documents the service URL domain allowlist: - Allowed hostnames by cloud environment preset - How to add custom domains via `additionalAllowedDomains` - Sovereign cloud FQDNs that require manual configuration - How to disable validation with wildcard `*` - Note on proactive messaging ## Test plan - [x] Docusaurus builds without errors - [x] New page renders correctly for all 3 languages - [x] Admonitions render correctly
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corinagum
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Apr 28, 2026
## Summary Reverting the serviceUrl allowlist defense-in-depth feature before public release. Open design questions on the work item (default sovereign cloud domains, narrowing of `*.botframework.com`, applying to proactive `ConversationReference`s, consultation with APX) should be resolved before this becomes part of the public API surface. This feature has not shipped in any release. Removing the public `additional_allowed_domains` option is a breaking change for anyone building from `main`, which is not ideal but acceptable since no release has been cut. Reverting now buys time to discuss without breaking customers later. ## Removed - `is_allowed_service_url` helper - `additional_allowed_domains` option on `AppOptions`/`InternalAppOptions`, plus plumbing through `App` -> `HttpServer` -> `TokenValidator` (`for_service`, `for_entra`, `validate_token`) - `CloudEnvironment.allowed_service_urls` field and per-cloud entries (PUBLIC/US_GOV/US_GOV_DOD/CHINA) - Service URL hostname check in `HttpServer.handle_request` - All allowlist tests in `test_token_validator.py` and `test_http_server.py` ## Preserved (other security work bundled into PR #370) - Scope validation (exact set membership) - Issuer validation logging when `tenant_id` is missing in `for_entra` ## Preserved (sovereign cloud, separate work) `CloudEnvironment` presets, `with_overrides`, `from_name`, `cloud` option on `App`, and the `cloud` parameter on `TokenValidator` factories are unchanged. ## Test plan - [x] `uv run ruff check` clean (full repo) - [x] `uv run pyright` clean (full repo, 0 errors / 0 warnings) - [x] `uv run pytest packages/apps/tests/`: 246 tests pass - [x] Smoke test: `examples/echo` starts and uvicorn binds to port --------- Co-authored-by: Claude Opus 4.7 (1M context) <[email protected]>
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Summary
Security hardening for token validation, service URL handling, and development tooling.
serviceUrlagainst allowed hostnames from the configured cloud environment preset. Configurable viaadditional_allowed_domainsfor non-standard channels or sovereign clouds without presets.Test plan
PYTHON_ENV=production