Authentication mechanism absence or evasion In fuxa-server
Description
FUXA has an unauthenticated arbitrary tag value disclosure via /api/getTagValue
Summary
An authorization bypass in the /api/getTagValue endpoint allows unauthenticated access to tag values when the referenced script does not exist.
Details
The issue is caused by the combination of these code paths:
server/api/apikeys/verify-api-or-token.js:45 sends requests without x-api-key to authJwt.verifyToken(req, res, next).
server/api/jwt-helper.js:46-64 creates a signed guest token when no x-access-token is provided:
if (!token) { token = getGuestToken(); }
and then populates req.userId / req.userGroups from that guest token.
server/api/command/index.js:76-105 exposes /api/getTagValue.
server/runtime/scripts/index.js:106-111 returns true when the referenced script does not exist:
if (!script) { return true; }
As a result, an unauthenticated request reaches /api/getTagValue as guest, and the authorization check is bypassed because isAuthorisedByScriptName() returns true when sourceScriptName is omitted or does not match a real script. The endpoint then returns arbitrary tag values by ID.
PoC
Requests to /api/getTagValue without authentication could succeed when the authorization logic evaluated a non-existent sourceScriptName as authorized.
Mitigation
Update Impact
Minimal update. May introduce new vulnerabilities or breaking changes.
Ecosystem | Package | Affected version | Patched versions |
|---|---|---|---|
 npm | 1.3.1 |
Aliases
References