GHSA-5f5r-95pg-xrpm

Описание

Summary

Some API endpoints in the Beszel hub accept a user-supplied system ID and proceed without further checks that the user should have access to that system. As a result, any authenticated user can access these routes for any system if they know the system's ID.

System IDs are random 15 character alphanumeric strings, and are not exposed to all users. However, it is theoretically possible for an authenticated user to enumerate a valid system ID via web API. To use the containers endpoints, the user would also need to enumerate a container ID, which is 12 digit hexadecimal string.

Affected Component

• File: internal/hub/api.go, lines 283–361
• Endpoints:
  • GET /api/beszel/containers/logs?system=SYSTEM_ID&container=CONTAINER_ID
  • GET /api/beszel/containers/info?system=SYSTEM_ID&container=CONTAINER_ID
  • GET /api/beszel/systemd/info?system=SYSTEM_ID&service=SERVICE_NAME
  • POST /api/beszel/smart/refresh?system=SYSTEM_ID
• Commit: c7261b56f1bfb9ae57ef0856a0052cabb2fd3b84

Vulnerable Code

The containerRequestHandler function retrieves a system by ID but never verifies the authenticated user is a member of that system:

The same pattern applies to getSystemdInfo (lines 322–340) and refreshSmartData (lines 342–361).

Meanwhile, the standard PocketBase collection API enforces proper membership checks:

These rules are only applied to the PocketBase collection endpoints, not to the custom routes registered on apiAuth.

PoC

The proof: The standard PocketBase API returns 404 (system not found) for unassigned systems. The custom endpoints resolve the system, contact the agent, and return data — proving the authorization check is missing.

Step 1: Start the hub

Wait a few seconds, then verify:

Expected: {"message":"API is healthy.","code":200,"data":{}}

Step 2: Create User A (admin)

Open http://localhost:8090 in a browser and create the first user:

• Email: usera@test.com
• Password: testpassword1

Step 3: Create User B (readonly)

In the Beszel UI, go to Users and add a new user:

• Email: userb@test.com
• Password: testpassword2
• Role: readonly

Step 4: Authenticate as User A

Step 5: Get hub public key

Step 6: Create a universal token and start the agent

Find the Docker network the hub is on:

Start the agent on the same network so the hub can reach it:

Wait a few seconds for the agent to register:

Step 7: Verify User A sees the system

You should see one system in items. Save the system ID:

Step 8: Authenticate as User B (readonly)

Verify User B sees NO systems:

Expected: "totalItems": 0

Step 9: Control test — standard API blocks User B

Expected: 404 — RBAC correctly hides the system from User B.

Step 10: IDOR — SMART refresh (User B triggers action on User A's system)

Expected: The hub processes the request and contacts the agent. Any response (data or agent error) proves the IDOR — compare with the 404 from Step 9.

Step 11: IDOR — Systemd info (User B reads from User A's system)

Expected: Hub contacts the agent and returns systemd data or an agent-level error.

Step 12: IDOR — Container logs (User B reads from User A's system)

Container endpoints require a Docker container ID (12-64 hex chars). Get a real one from the agent's host:

Step 13: IDOR — Container info (User B reads from User A's system)

Impact

• Container logs: Content of recent application logs, potentially including sensitive information
• Container info: Content of Docker engine API's /containers/{id}/json endpoint, excluding environment variables
• Systemd info: Unit properties and status for any monitored service
• SMART refresh: Trigger a SMART data update on any system