I have configured app registration with client certificate .cer file in azure
Using jwt.io to create client assertion, and requested access token as in below screenshot
There were few posts about issues with key not found, but in this scenario key Is not able to generate signature. unable to understand the issue here. I used private key and public key in jwt.to to generate client assertion.
Header in JWt used base64 thumbprint value-
{
"alg": "RS256",
"typ": "JWT",
"x5t": "hfbTrE31AcSETk1BFhovA1w1SMc="
}
However, signature is verified in jwt.io.
TIA
I have figured this out, its issue in Private/public key. Extract Private key as PKCS #8 to use in building jwt assertion.
Verify Signature gives error with encrypted Private key, use decrypted private key
Related
I don't understand why I should use the public key in signing JWT. The private key is there so that the JWT token cannot be forged, yes? But why additionally sign it with a public key? Are there any benefits? Because I don't understand it at all. After all, a JWT signed with a private key can be read without the public key. What is this public key for?
Signing a JWT means you take the cleartext, signing it with a key - either the private key from an RSA pair or a symmetric key, then add the signature to the JWT. The JWT itself is still readable without decrtypting the signature. But someone with the key can decrypt the signature and confirm the contents match the cleartext.
The advantage of using RSA over symmetric key is that anyone can verify the signature without them having to have a secret key. You can either pass the public key to the JWT recipient over a side channel, or if using OAuth2 it provides a URL to access public keys.
You would use the public key for encrypting, not signing. You encrypt with the recipient's public key so that only the recipient can decrypt it.
I am trying to decrypt JWT token and verify signature using python. Though I found PyJWT, it does not actually encrypt/decrypt the payload, so I cannot use it. I also looked at https://github.com/IdentityPython/pyjwkest/tree/master/src/jwkest but the decrypt() method is actually returning plain text and then not sure how to "verify" on the plain text.
Can someone share example for decrypt a JWT token using private key and verify the signature using public key. Algo for decrypt: RSA-OAEP-256 and enc: A256GCM. Algo for signing was PS512
By following this MS info about client credential grants, I got a JWT token:
eyJ0eXAiOiJKV1QiLCJub25jZSI6InBOWU1CVkZKcFAxVjJ1VTFaUnM1V3NOLVhyeDhjXzhWWjU5RWxhTFZBeDAiLCJhbGciOiJSUzI1NiIsIng1dCI6IllNRUxIVDBndmIwbXhvU0RvWWZvbWpxZmpZVSIsImtpZCI6IllNRUxIVDBndmIwbXhvU0RvWWZvbWpxZmpZVSJ9.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.fy2TIhXb89Ic2wuw7ysao-JzBqzpQGHD29A_X-JrjeEXOTvO5AB75tn0G1zV69vYkg2hEMsv3Dej5pNJ82w8NETRXMEEhC6ke9-URk0uKzWJ_ZzxNrL9I1eD8N4UUhqXeJifYE9gatDRqSfFmEn5eQbRVgEegJMmpqb7DMeUH8pOkTZLKzFHjSmJATx2eQBkW1PiMEL5u-QuIiZohObxficQ8PvK-IgE2V_LcTuVnEVXBrgYfZllPesQTP9-fjV_iGnM5gwcnVhwqNdpk9Ws-Vz2XDgRRCDu604IbYv3SvA9JhbKByo0CPreMfhqjrP5l_0Rm_bJeGj9iJrql5Jj3w
When I simply copy-paste it to jwt.io, the token is correctly decoded but its signature validation fails.
So I suspected jwt.io not to work properly and wanted to verify the token myself.
The token's header:
{
"typ": "JWT",
"nonce": "pNYMBVFJpP1V2uU1ZRs5WsN-Xrx8c_8VZ59ElaLVAx0",
"alg": "RS256",
"x5t": "YMELHT0gvb0mxoSDoYfomjqfjYU",
"kid": "YMELHT0gvb0mxoSDoYfomjqfjYU"
}
According to this description where the Azure public keys/certificates are available I fetched them and the key with kid=YMELHT0gvb0mxoSDoYfomjqfjYU is there:
{
"kty":"RSA",
"use":"sig",
"kid":"YMELHT0gvb0mxoSDoYfomjqfjYU",
"x5t":"YMELHT0gvb0mxoSDoYfomjqfjYU",
"n":"ni9SAyu9EsltQlV7Jo3wMUvcpYb4mmfHzV4IsDZ6NQvJjtQJuhsfqiG86VntMd76R44kCmkfMGvtQRA2_UmnVBSSLxQKvcGUqNodH7YaMYOTmHlbOSoVpi3Ox2wj6cWvhaTTm_4xzJ3F0yF0Y_aRBMxSCIwLv3nTMRNe74k4zdBnhL7k5ObOY_vUGt_5-sPo6BXoV7oov4Ps6jeyUdRKtqVZSp5_kzz16kPh1Ng_2tn4vpQimNbHRralq8rNM_gOLPAar6v7mL_qsqpgx-48e5ENFxikbB-NzAmLll1QSkzciu2rCjFGH4j_-bCHr7FxUNDL_E0vMFVDFw8SUlYMgQ",
"e":"AQAB",
"x5c":[
"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"
],
"issuer":"https://login.microsoftonline.com/{tenantid}/v2.0"
}
Next I extract the public key from the certificate:
openssl x509 -in ms_signing_cert4.pem -pubkey -noout
-----BEGIN PUBLIC KEY----- MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAni9SAyu9EsltQlV7Jo3w
MUvcpYb4mmfHzV4IsDZ6NQvJjtQJuhsfqiG86VntMd76R44kCmkfMGvtQRA2/Umn
VBSSLxQKvcGUqNodH7YaMYOTmHlbOSoVpi3Ox2wj6cWvhaTTm/4xzJ3F0yF0Y/aR
BMxSCIwLv3nTMRNe74k4zdBnhL7k5ObOY/vUGt/5+sPo6BXoV7oov4Ps6jeyUdRK
tqVZSp5/kzz16kPh1Ng/2tn4vpQimNbHRralq8rNM/gOLPAar6v7mL/qsqpgx+48
e5ENFxikbB+NzAmLll1QSkzciu2rCjFGH4j/+bCHr7FxUNDL/E0vMFVDFw8SUlYM
gQIDAQAB
-----END PUBLIC KEY-----
And lastly I use the Python PyJWT library to verify the signature:
import jwt
token = 'eyJ0eXAiOiJKV1QiLCJub25jZSI6InBOWU1CVkZKcFAxVjJ1VTFaUnM1V3NOLVhyeDhjXzhWWjU5RWxhTFZBeDAiLCJhbGciOiJSUzI1NiIsIng1dCI6IllNRUxIVDBndmIwbXhvU0RvWWZvbWpxZmpZVSIsImtpZCI6IllNRUxIVDBndmIwbXhvU0RvWWZvbWpxZmpZVSJ9.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.fy2TIhXb89Ic2wuw7ysao-JzBqzpQGHD29A_X-JrjeEXOTvO5AB75tn0G1zV69vYkg2hEMsv3Dej5pNJ82w8NETRXMEEhC6ke9-URk0uKzWJ_ZzxNrL9I1eD8N4UUhqXeJifYE9gatDRqSfFmEn5eQbRVgEegJMmpqb7DMeUH8pOkTZLKzFHjSmJATx2eQBkW1PiMEL5u-QuIiZohObxficQ8PvK-IgE2V_LcTuVnEVXBrgYfZllPesQTP9-fjV_iGnM5gwcnVhwqNdpk9Ws-Vz2XDgRRCDu604IbYv3SvA9JhbKByo0CPreMfhqjrP5l_0Rm_bJeGj9iJrql5Jj3w'
pub_key = b'-----BEGIN PUBLIC KEY-----\nMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAni9SAyu9EsltQlV7Jo3w\nMUvcpYb4mmfHzV4IsDZ6NQvJjtQJuhsfqiG86VntMd76R44kCmkfMGvtQRA2/Umn\nVBSSLxQKvcGUqNodH7YaMYOTmHlbOSoVpi3Ox2wj6cWvhaTTm/4xzJ3F0yF0Y/aR\nBMxSCIwLv3nTMRNe74k4zdBnhL7k5ObOY/vUGt/5+sPo6BXoV7oov4Ps6jeyUdRK\ntqVZSp5/kzz16kPh1Ng/2tn4vpQimNbHRralq8rNM/gOLPAar6v7mL/qsqpgx+48\ne5ENFxikbB+NzAmLll1QSkzciu2rCjFGH4j/+bCHr7FxUNDL/E0vMFVDFw8SUlYM\ngQIDAQAB\n-----END PUBLIC KEY-----'
print(jwt.decode(token, pub_key, algorithms=['RS256']))
Results in
jwt.exceptions.InvalidSignatureError: Signature verification failed
I tried to generate on my PC my own JWT, also signed by RS256 - passes both on jwt.io and PyJWT. Same for a sample token I found somewhere on the web. Just cannot handle tokens issued by AAD.
What am I missing with these AAD tokens?
Many thanks.
Your token is correct. It is just a specific token for graph api. You will see a nonce in Jwt.Header. This means you need special processing. Normal processing will fail.
If you're a client getting a token for Graph, assume that it's an
encrypted string that you should never look at - sometimes it will be.
We use a special token format for Graph that they know how to validate
- you shouldn't be looking at access tokens if they're not for you.
See the details here.
Reference:
Can not validate signature
Yes indeed. This nonce is in V2, the addition to the V1 token.
I used to validate V1 using this snippet:
var signatureKey = signatureKeyIdentifier.X509CertificateChain.First();
var certificate = new X509Certificate2(signatureKey.ToBytesFromBase64URLString());
var rsa = certificate.GetRSAPublicKey();
var data = string.Format("{0}.{1}", header, payload).ToBytes();
var isValidSignature = rsa.VerifyData(
data,
signature.ToBytesFromBase64URLString(),
HashAlgorithmName.SHA256,
RSASignaturePadding.Pkcs1);
But now this validation will fail.
Please note that I am creating a certificate as provided by header.
The nonce has nothing to do with signature, it is just a number that changes for each request/token to make sure no one is replaying that valid token. Validating the nonce is by saving all of them in a database and check uniqueness.
I think we need to find out the changes in calculating the signation. are they still using the same padding? same Algo?
The way I am using to validate now is to send that token to the same active directory to get data, then AD will give the data ONLY upon valid token.
I am having this issue while logging ADFS SSO. "No decryption key for encrypted SAML response".
Login from another account is being successful. Someone can help me with this. I am using Express with passport-saml work.
This is code snap where I am stuck.
node_modules/passport-saml/lib/passport-saml/saml.js in null. at line 623:15
if (encryptedAssertions.length == 1) {
if (!self.options.decryptionPvk)
throw new Error('No decryption key for encrypted SAML response');
var encryptedAssertionXml = encryptedAssertions[0].toString();
How encryption works in SAML: identity provider encrypts some elements of the SAML response with service provider's public key. The service provider decrypts using the private key that corresponds to the public key used to encrypt. In other words, the service provider needs to own a keypair - private key and public key - for this use case to work.
The private key of the aforementioned keypair needs to be configured via decryptionPvk parameter in passport-saml. Since the assertion is encrypted yet no private key is found in decryptionPvk, passport-saml complains.
Either remove the encryption on ADFS side or provide the private key to passport-saml.
I am following this guide to the client credentials flow and this guide to the JWT token needed. The ultimate objective is to access calendar information through the Microsoft Graph API. Calls to the Graph API need to be authenticated with an access token which is obtained from the Microsoft token endpoint.
But calling the token endpoint itself requires some form of authentication, which can be either by shared secret or by a certificate-signed JWT token. The shared secret approach is well-documented and appears to work fine, except that the Graph service I am trying to call rejects the access token as not secure enough - it seems a certificate-signed JWT token is required. I have been unable to find any Java examples of this second approach, and what I have implemented so far following the above guides doesn't work.
Using JJWT, the code for generating the token looks like:
PrivateKey key = loadPrivateKey();
String jwt = Jwts.builder()
.setHeaderParam("typ", "JWT")
.setHeaderParam("alg", "RS256")
.setHeaderParam("x5t", "A7...89")
.setSubject(clientId)
.setExpiration(new Date(System.currentTimeMillis() + 200000))
.setIssuer(clientId)
.setNotBefore(new Date())
.setAudience("https://login.microsoftonline.com/" + tenantId + "/oauth2/token")
.setId(UUID.randomUUID().toString())
.signWith(
SignatureAlgorithm.RS256,
key)
.compact();
loadPrivateKey() uses BouncyCastle classes:
KeyFactory factory = KeyFactory.getInstance("RSA");
PemObject pemObject;
PemReader pemReader = new PemReader(new StringReader(pemFileContent));
try {
pemObject = pemReader.readPemObject();
} finally {
pemReader.close();
}
byte[] content = pemObject.getContent();
PKCS8EncodedKeySpec privKeySpec = new PKCS8EncodedKeySpec(content);
return factory.generatePrivate(privKeySpec);
I created a key pair in the apps.dev.microsoft.com console, downloaded the private key and converted it to PEM format using openssl, then pasted the PEM content into the pemFileContent variable used above. openssl calculates the same thumbprint for the PEM version as the MS application console.
I use the JWT token in a call to a Retrofit service:
default Call<APIToken> getAccessToken(String tenantId, String clientId, String clientAssertion)
{
return this.getAccessToken(
tenantId,
clientId,
clientAssertion,
"urn:ietf:params:oauth:client-assertion-type:jwt-bearer",
"https://graph.microsoft.com/.default",
"client_credentials");
}
#FormUrlEncoded
#Headers({
"Host: login.microsoftonline.com",
"Content-Type: application/x-www-form-urlencoded"
})
#POST("/{tenant_id}/oauth2/token")
Call<APIToken> getAccessToken(
#Path("tenant_id") String tenantId,
#Field("client_id") String clientId,
#Field("client_assertion") String clientAssertion,
#Field("client_assertion_type") String clientAssertionType,
#Field("scope") String scope,
#Field("grant_type") String grantType);
Everything looks good in the debugging output:
header={typ=JWT, alg=RS256, x5t=A7...89},body={sub=b0a0fd13-1e86-4ef3-a003-c53eaf21daa4, exp=1517656715, iss=b0a0fd13-1e86-4ef3-a003-c53eaf21daa4, nbf=1517656515, aud=https://login.microsoftonline.com/87ad3067-2703-49ea-8cd2-a094fc3ee413/oauth2/token, jti=4fa5db4f-76b7-4122-9c5a-092ac74fd0fa},signature=....342 characters....
But the response is 401 Unauthorized, with the error report:
{"error":"invalid_client","error_description":"AADSTS70002: Error validating credentials. AADSTS50012: Client assertion contains an invalid signature. [Reason - The key was not found., Thumbprint of key used by client: '03B....3D', Configured keys: [Key0:Start=02/03/2018, End=12/31/2099, Thumbprint=lQ...M4;]]\r\nTrace ID: b4775394-51cc-4a4a-b927-50bd05421100\r\nCorrelation ID: f9264339-9b85-4942-9404-af941aa0331c\r\nTimestamp: 2018-02-03 11:15:18Z","error_codes":[70002,50012],"timestamp":"2018-02-03 11:15:18Z","trace_id":"b4775394-51cc-4a4a-b927-50bd05421100","correlation_id":"f9264339-9b85-4942-9404-af941aa0331c"}
I am at a loss as to where to look for the problem. Neither of the thumbprint values mentioned in the error correspond to the thumbprint of the private key. Others have reported this error message when using the wrong signature algorithm, but RS256 is the documented algorithm to use. I'm looking for either a pointer to what I'm getting wrong, or a working example in Java (I'm not fussy about which libraries are used) of the client credentials flow using a signed JWT token (I have found examples using a shared secret, and they work OK, but the MS Graph API rejects the token as not being secure enough).