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.

Versions 4.2.1 and earlier of jsonwebtoken are affected by a verification bypass vulnerability. This is a result of weak validation of the JWT algorithm type, occuring when an attacker is allowed to arbitrarily specify the JWT algorithm.

Recommendation

Update to version 4.2.2 or later.

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

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.

Affected versions of the jws package allow users to select what algorithm the server will use to verify a provided JWT. A malicious actor can use this behaviour to arbitrarily modify the contents of a JWT while still passing verification. For the common use case of the JWT as a bearer token, the end result is a complete authentication bypass with minimal effort.

Recommendation

Update to version 3.0.0 or later.

Versions of base64url before 3.0.0 are vulnerable to to out-of-bounds reads as it allocates uninitialized Buffers when number is passed in input on Node.js 4.x and below.

Recommendation

Update to version 3.0.0 or later.

Affected versions of moment are vulnerable to a low severity regular expression denial of service when parsing dates as strings.

Recommendation

Update to version 2.19.3 or later.

Versions of moment prior to 2.11.2 are affected by a regular expression denial of service vulnerability. The vulnerability is triggered when arbitrary user input is passed into moment.duration().

Proof of concept

var moment = require('moment');

var genstr = function (len, chr) {
    var result = "";
    for (i=0; i<=len; i++) {
        result = result + chr;
    }

    return result;
}


for (i=20000;i<=10000000;i=i+10000) {
    console.log("COUNT: " + i);
    var str = '-' + genstr(i, '1')
    console.log("LENGTH: " + str.length);
    var start = process.hrtime();
    moment.duration(str)

    var end = process.hrtime(start);
    console.log(end);
}

Results

$ node moment.js
COUNT: 20000
LENGTH: 20002
[ 0, 618931029 ]
COUNT: 30001
LENGTH: 30003
[ 1, 401413894 ]
COUNT: 40002
LENGTH: 40004
[ 2, 437075303 ]
COUNT: 50003
LENGTH: 50005
[ 3, 824664804 ]
COUNT: 60004
LENGTH: 60006
[ 5, 651335262 ]

Recommendation

Please update to version 2.11.2 or later.

Impact

This vulnerability impacts npm (server) users of moment.js, especially if user provided locale string, eg fr is directly used to switch moment locale.

Patches

This problem is patched in 2.29.2, and the patch can be applied to all affected versions (from 1.0.1 up until 2.29.1, inclusive).

Workarounds

Sanitize user-provided locale name before passing it to moment.js.

References

Are there any links users can visit to find out more?

For more information

If you have any questions or comments about this advisory:

• Open an issue in moment repo