Vendor Metadata Management
Metadata Service:#
The metadata service is a centralized, trusted database of FIDO authenticators. It is used by the Relying Party to validate authenticators i.e. attest the genuine-ness of a device. If implemented in organizations like government, federal agencies, banking and healthcare organizations for example) and/or organizations handling sensitive data (media companies, R&D institutions, corporations, etc), this information can help protect organizations against security vulnerabilities.
1. Local metadata service:#
Janssen's FIDO server has a configuration parameter called serverMetadataFolder which by default points to a directory location /etc/jans/conf/fido2/server_metadata where the administrator can (obtain from a vendor and ) place authenticator metadata in json format.
Example of authenticator metadata:
{
"aaguid": "83c44309-....-8be444b573cb",
"metadataStatement": {
"legalHeader": "Submission of this statement and retrieval and use of this statement indicates acceptance of the appropriate agreement located at https://fidoalliance.org/metadata/metadata-legal-terms/.",
"aaguid": "83c44309-....-8be444b573cb",
"description": "Just an example",
"authenticatorVersion": 448962,
"protocolFamily": "fido2",
"schema": 3,
"upv": [
{
"major": 1,
"minor": 0
},
{
"major": 1,
"minor": 1
}
],
"authenticationAlgorithms": [
"ed25519_eddsa_sha512_raw",
"secp256r1_ecdsa_sha256_raw"
],
"publicKeyAlgAndEncodings": [
"cose"
],
"attestationTypes": [
"basic_full"
],
"userVerificationDetails": [
[
{
"userVerificationMethod": "passcode_external",
"caDesc": {
"base": 64,
"minLength": 4,
"maxRetries": 8,
"blockSlowdown": 0
}
},
{
"userVerificationMethod": "presence_internal"
}
],
[
{
"userVerificationMethod": "passcode_external",
"caDesc": {
"base": 64,
"minLength": 4,
"maxRetries": 8,
"blockSlowdown": 0
}
}
],
[
{
"userVerificationMethod": "fingerprint_internal",
"baDesc": {
"selfAttestedFRR": 0,
"selfAttestedFAR": 0,
"maxTemplates": 5,
"maxRetries": 5,
"blockSlowdown": 0
}
},
{
"userVerificationMethod": "presence_internal"
}
],
[
{
"userVerificationMethod": "none"
}
],
[
{
"userVerificationMethod": "fingerprint_internal",
"baDesc": {
"selfAttestedFRR": 0,
"selfAttestedFAR": 0,
"maxTemplates": 5,
"maxRetries": 5,
"blockSlowdown": 0
}
}
],
[
{
"userVerificationMethod": "presence_internal"
}
]
],
"keyProtection": [
"hardware",
"secure_element"
],
"matcherProtection": [
"on_chip"
],
"cryptoStrength": 128,
"attachmentHint": [
"external",
"wired"
],
"tcDisplay": [],
"attestationRootCertificates": [
"MII....psmyPzK+Vsgw2jeRQ5JlKDyqE0hebfC1tvFu0CCrJFcw=="
],
"icon": "data:image/png;base64,iVBORw0KGgoAAAA....k5+36hF7vXAAAAAElFTkSuQmCC",
"authenticatorGetInfo": {
"versions": [
"FIDO_2_0",
"FIDO_2_1_PRE",
"FIDO_2_1"
],
"extensions": [
"credProtect",
"hmac-secret",
"largeBlobKey",
"credBlob",
"minPinLength"
],
"aaguid": "83c.....73cb",
"options": {
"plat": false,
"rk": true,
"clientPin": true,
"up": true,
"uv": false,
"pinUvAuthToken": true,
"largeBlobs": true,
"ep": false,
"bioEnroll": false,
"userVerificationMgmtPreview": false,
"authnrCfg": true,
"credMgmt": true,
"credentialMgmtPreview": true,
"setMinPINLength": true,
"makeCredUvNotRqd": false,
"alwaysUv": true
},
"maxMsgSize": 1200,
"pinUvAuthProtocols": [
2,
1
],
"maxCredentialCountInList": 8,
"maxCredentialIdLength": 128,
"transports": [
"usb"
],
"algorithms": [
{
"type": "public-key",
"alg": -7
},
{
"type": "public-key",
"alg": -8
}
],
"maxSerializedLargeBlobArray": 1024,
"forcePINChange": false,
"minPINLength": 4,
"firmwareVersion": 328965,
"maxCredBlobLength": 32,
"maxRPIDsForSetMinPINLength": 1,
"preferredPlatformUvAttempts": 3,
"uvModality": 2,
"remainingDiscoverableCredentials": 25
}
},
"statusReports": [
{
"status": "FIDO_CERTIFIED_L1",
"effectiveDate": "2021-08-06",
"url": "www.yubico.com",
"certificationDescriptor": "An example",
"certificateNumber": "FIDO2.....001",
"certificationPolicyVersion": "1.3",
"certificationRequirementsVersion": "1.4"
},
{
"status": "FIDO_CERTIFIED",
"effectiveDate": "2021-08-06"
}
],
"timeOfLastStatusChange": "2021-08-16"
}
2. Metadata service for authenticators approved by FIDO Alliance (MDS3)#
Metadata entries for trusted authenticators registered with FIDO Alliance can be found on - https://fidoalliance.org/certification/fido-certified-products/
Draw.io reference for image:
<?xml version="1.0" encoding="UTF-8"?>
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Janssen's FIDO2 server -
- Downloads, verifies and caches metadata BLOBs from the FIDO Metadata Service.
- Re-downloads the metadata BLOB when it expires.
- Provides trust root certificates for verifying attestation statements during credential registrations.
3. Skip metadata validation#
Metadata validation is recommended but not mandatory as per FIDO2 specifications.
In FIDO2 we can disable this validation by setting the attestionMode parameter (default is
monitor).
It should look something like this:
"fido2Configuration": {
...,
"attestationMode": "disabled",
...
}
4. How Apple does it differently#
If you check attStmt and it contains x5c, it is a FULL attestation. FULL basically means that it is a certificate
that is chained to the vendor. It's signed by a batch private key whose public key is in a batch certificate that is
chained to the Apple attestation root certificate. Usually certificates have an authorityInfoAccess extension that helps
locate the root, but Apple chose not to do that. Nevertheless, a quick google give us the needed root
certificate https://www.apple.com/certificateauthority/Apple_WebAuthn_Root_CA.pem.
This certificate is downloaded to the path /etc/jans/conf/fido2/authenticator_cert.
You can see more details of the implementation in this link from https://medium.com/webauthnworks/webauthn-fido2-verifying-apple-anonymous-attestation-5eaff334c849.
References:#
- https://fidoalliance.org/announcing-the-new-streamlined-and-simplified-metadata-service-for-authenticator-vendors-and-customers/
Created: 2022-07-07
