In jsonwebtoken node module before 4.2.2 it is possible for an attacker to bypass verification when a token digitally signed with an asymmetric key (RS/ES family) of algorithms but instead the attacker send a token digitally signed with a symmetric algorithm (HS family).
Overview
Versions <=8.5.1 of jsonwebtoken library could be misconfigured so that legacy, insecure key types are used for signature verification. For example, DSA keys could be used with the RS256 algorithm.
Am I affected?
You are affected if you are using an algorithm and a key type other than the combinations mentioned below
| Key type | algorithm | |----------|------------------------------------------| | ec | ES256, ES384, ES512 | | rsa | RS256, RS384, RS512, PS256, PS384, PS512 | | rsa-pss | PS256, PS384, PS512 |
And for Elliptic Curve algorithms:
| alg | Curve | |-------|------------| | ES256 | prime256v1 | | ES384 | secp384r1 | | ES512 | secp521r1 |
How do I fix it?
Update to version 9.0.0. This version validates for asymmetric key type and algorithm combinations. Please refer to the above mentioned algorithm / key type combinations for the valid secure configuration. After updating to version 9.0.0, If you still intend to continue with signing or verifying tokens using invalid key type/algorithm value combinations, you’ll need to set the allowInvalidAsymmetricKeyTypes option to true in the sign() and/or verify() functions.
Will the fix impact my users?
There will be no impact, if you update to version 9.0.0 and you already use a valid secure combination of key type and algorithm. Otherwise, use the allowInvalidAsymmetricKeyTypes option to true in the sign() and verify() functions to continue usage of invalid key type/algorithm combination in 9.0.0 for legacy compatibility.
Overview
In versions <=8.5.1 of jsonwebtoken library, lack of algorithm definition and a falsy secret or key in the jwt.verify() function can lead to signature validation bypass due to defaulting to the none algorithm for signature verification.
Am I affected? You will be affected if all the following are true in the jwt.verify() function: - a token with no signature is received - no algorithms are specified - a falsy (e.g. null, false, undefined) secret or key is passed
How do I fix it? Update to version 9.0.0 which removes the default support for the none algorithm in the jwt.verify() method.
Will the fix impact my users?
There will be no impact, if you update to version 9.0.0 and you don’t need to allow for the none algorithm. If you need 'none' algorithm, you have to explicitly specify that in jwt.verify() options.
Token validation methods are susceptible to a timing side-channel during HMAC comparison. With a large enough number of requests over a low latency connection, an attacker may use this to determine the expected HMAC.
Overview
Versions <=8.5.1 of jsonwebtoken library can be misconfigured so that passing a poorly implemented key retrieval function (referring to the secretOrPublicKey argument from the readme link) will result in incorrect verification of tokens. There is a possibility of using a different algorithm and key combination in verification than the one that was used to sign the tokens. Specifically, tokens signed with an asymmetric public key could be verified with a symmetric HS256 algorithm. This can lead to successful validation of forged tokens.
Am I affected?
You will be affected if your application is supporting usage of both symmetric key and asymmetric key in jwt.verify() implementation with the same key retrieval function.
How do I fix it? Update to version 9.0.0.
Will the fix impact my users?
There is no impact for end users