Fleet: Observer-level enrollment secret extraction via ORDER BY oracle on Apple MDM commands endpoint

QFinch assessment

A vulnerability in Fleet's Apple MDM commands listing endpoint allowed authenticated users with the lowest-privilege Observer role to extract sensitive values from joined database tables — including host enrollment secrets and Apple Push Notification Service (APNS) tokens — through a cursor-based binary search oracle. The endpoint accepted a user-supplied orderkey parameter that was not validated against a column allowlist.

Potential impact

The GET /api/v1/fleet/mdm/apple/commands endpoint constructs its query using a deprecated helper that did not restrict which columns could appear in the ORDER BY clause. The underlying query joins the hosts and nanoenrollments tables, so any column on those tables could be supplied as orderkey. An attacker with Observer credentials could then use the cursor-based pagination parameter (after) to binary-search the value of the chosen column one character at a time. The targeted values never appeared in the response body, but the presence or absence of results revealed each character. With extracted nodekey or orbitnodekey values, an attacker could impersonate enrolled hosts to Fleet's osquery and Orbit endpoints, submit fabricated host data, and retrieve pending scripts and commands. The APNS values are exploitable only by a party that also possesses the organization's APNS certificate. Exploitation required authenticated Observer access and a Fleet deployment with Apple MDM enabled and at least one queued MDM command. Instances without Apple MDM configured were not affected.