Is @microsoft/teams.apps safe?
What @microsoft/teams.apps does
@microsoft/teams.apps is a TypeScript library for building Microsoft Teams agents, tabs and message extensions. It is published by Microsoft on npm from the microsoft/teams.ts repository under the MIT license and needs Node.js 22.12 or later. It routes Teams activities, validates incoming requests, sends replies and proactive notifications, and handles OAuth sign-in and Microsoft Graph access. It can start its own HTTP server or plug into an existing one such as Express, receiving activities at /api/messages by default. The latest npm release declares no install scripts. Before installing, keep the dangerouslyAllowUnauthenticatedRequests option off outside local testing, since it skips Teams service token validation.
- Node.js filesystem write/delete
- Node.js network egress
- Delegated authentication (OAuth 2.0 / OIDC)
What to do: Nothing here argues against installing it. Grant the capabilities it lists only if you expect the tool to need them.
@microsoft/teams.apps is an npm package analyzed by SkillTotal's deterministic static scanner. The scan found no malicious indicators. It can: delegated authentication, filesystem write and network egress — capabilities are what the code can do, not a verdict on intent. Risk score 0/100 (low).
@microsoft/ teams.apps 2.2.1
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Automated static-analysis result. It can contain false positives and false negatives, and is not a claim about the intent of @microsoft/teams.apps's authors. Report a false positive.
Behavioral traits
How this component maps to the CSA agentic threat model. Descriptive — it never affects the risk score.
Findings (3)
The component writes or deletes files on disk.
await (0, promises_1.writeFile)(path, this.bytes, { signal: options?.signal });const writable = (0, fs_1.createWriteStream)(path);
Why it matters: Usually legitimate, but worth confirming the paths can't be controlled by untrusted input.
Fix: Confirm which files are written/deleted and that paths cannot be influenced by untrusted input.
The component makes outbound network requests.
const axios_1 = require("axios");return fromFetchResponse(await options.fetch(url, {import http from 'http';
const http_1 = __importDefault(require("http"));const axios_1 = require("axios");if ((0, axios_1.isAxiosError)(err) && err.response?.status === 409 && err.response.data?.error?.code === 'PlanConflict') {import { AxiosError } from 'axios';const axios_1 = require("axios");const axios_1 = require("axios");import http from 'http';
const http_1 = __importDefault(require("http"));import { AxiosError } from 'axios';const axios_1 = require("axios");{ regex: /fetch\(\s*["']([^"']+)["']/gi, source: 'fetch()' },Why it matters: Usually legitimate, but confirm the destinations are expected and no sensitive data leaves.
Fix: Confirm the destination hosts are expected and that no sensitive data is sent off-host.
An OAuth 2.0 / OpenID Connect delegated-authentication flow was detected (authorization-code / refresh-token / token-exchange grant, an OIDC authorize/discovery endpoint or id_token, or a delegation library). Tools authenticate with the end user's delegated, scoped credentials rather than a long-lived embedded service credential. (3 occurrence(s) shown as evidence).
const msal_node_1 = require("@azure/msal-node");this._msalLogger = this.logger.child('azure/msal-node', {pattern: '-azure/msal-node'
Fix: Delegated auth is a lower-blast-radius execution context than an embedded static credential. Confirm the requested scopes are minimal and that tokens are never logged or forwarded off-host.
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