How the CVE Works:
The vulnerability in the APIExport Virtual Workspace allows unauthorized creation and deletion of objects in arbitrary target workspaces. By design, access to these workspaces should be restricted to API providers with explicit permission via APIBindings. However, this flaw enables attackers to bypass these restrictions, even in the absence of an APIBinding or when permission claims are explicitly rejected. This occurs due to insufficient authorization checks in the APIExport VirtualWorkspace implementation, allowing attackers to manipulate resources without proper validation.
DailyCVE Form:
Platform: kcp
Version: <0.26.3, <0.27.0
Vulnerability: Unauthorized Object Manipulation
Severity: Critical
Date: 2024-XX-XX
What Undercode Say:
Exploitation:
1. Exploit Code:
An attacker can craft malicious API requests to the APIExport VirtualWorkspace endpoint to create or delete objects in unauthorized workspaces.
Example:
curl -X POST -H "Authorization: Bearer <token>" -d '{"object": "malicious"}' https://<kcp-endpoint>/apis/export/virtualworkspaces/<workspace>/resources
2. Reverse Proxy Bypass:
If reverse proxies are not configured to enforce strict authorization, attackers can exploit this vulnerability by sending crafted requests directly to the APIExport endpoint.
Protection:
1. Upgrade:
Upgrade to kcp 0.26.3 or 0.27.0 to apply the patch.
kubectl kcp upgrade --version 0.27.0
2. Access Control:
Restrict `apiexport/contentsub-resource` access to only trusted users.
Example:
apiVersion: rbac.authorization.k8s.io/v1 kind: Role metadata: name: restricted-apiexport-access rules: - apiGroups: [bash] resources: [bash] verbs: [bash]
3. Reverse Proxy Configuration:
Configure reverse proxies to enforce authorization logic similar to the patch.
Example (NGINX):
location /apis/export/virtualworkspaces/ {
if ($http_authorization !~ "Bearer valid-token") {
return 403;
}
proxy_pass http://kcp-backend;
}
4. Monitoring:
Monitor APIExport VirtualWorkspace logs for suspicious activity.
Example:
kubectl logs -n kcp-system -l app=kcp --tail=100 | grep "APIExport VirtualWorkspace"
5. Patch Validation:
Verify the patch by testing APIExport VirtualWorkspace endpoints after upgrade.
Example:
curl -X POST -H "Authorization: Bearer <token>" -d '{"object": "test"}' https://<kcp-endpoint>/apis/export/virtualworkspaces/<workspace>/resources
6. References:
- Pull Request: bash
- kcp Documentation: bash
By following these steps, organizations can mitigate the risk posed by this critical vulnerability and secure their kcp environments.
References:
Reported By: https://github.com/advisories/GHSA-w2rr-38wv-8rrp
Extra Source Hub:
Undercode
