Notes from the field: VMware Access with VMware UAG and JWT validation

It’s been a while since I’ve retested the setup with validating gateway request with JWT entries, because I thought it was depending on an appliance such as F5 for it to work. See Launching Horizon Resources Through Validating Gateways (

I did try and configure it none the less but never got it farther then just enabling JWT in Access with no audience enabled and the UAG also not configured with any WS1 for a working desktop, otherwise it would always error out with something like below:

Well that was then and this is now and here comes a very nice blog post by Nick Burton explaining how easy it is and just works. See Integrating Workspace ONE Access and UAG with JWT – Nick’s IT Blog (

Ok, mind blown and Nick and I got to some trial and error testing and checking the setup of the environments is different whatsoever. Everything seems to be in order.

This is the URL where you can check it btw:

https://<WS1 AccessURL>/SAAS/API/1.0/REST/auth/token?attribute=publicKey&format=pem

So digging in deeper and putting the UAG in DEBUG mode and reproducing the issue gave some interesting feedback in the JWT section of the UAG:

08/03 19:10:01,061[nioEventLoopGroup-10-1]INFO  jwt.JWTArtifactHelper[validateJWT: 215][][][Horizon][287c-***-dd51-***-7f3c-***-f651]: JWT rejected with error message : Unable to process JOSE object (cause: org.jose4j.lang.InvalidKeyException: An RSA key of size 2048 bits or larger MUST be used with the all JOSE RSA algorithms (given key was only 1024 bits).): JsonWebSignature{“typ”:”JWT”,”alg”:”RS256″,”kid”:”1624905951″}->eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiIsImtpZCI6IjE2MjQ5MDU5NTEifQ.eyJqdGkiOiI0M2RkOGY3OS1kNTc5LTRmMTEtYjI5Yi00M2Y4ZTY1NTEwNDAiLCJpc3MiOiJodHRwczovL3RlY2huaWNhbGZlbGxvdy1jb25zdWx0YW5jeS52bXdhcmVpZGVudGl0eS5kZS9TQUFTL2F1dGgiLCJhdWQiOlsiaHR0cHM6Ly91YWcudGVjaG5pY2FsZmVsbG93Lm5sIl0sImFydGlmYWN0IjoiQUFRQUFIVFJLZjJBTVFpMzJNNGxLOVRUMkFNUmRqdmhKVEdMTmErVDhzQVIxeW5DSndSalZFVlk3VlU9IiwidXBuIjoiaGhlcmVzQHRlY2huaWNhbGZlbGxvdy5jb20iLCJleHAiOjE2MjgwMTgwOTgsImlhdCI6MTYyODAxNzc5OH0.ffFHm8zqNyfNJGFl_-at_NL_gEa9PzC88iIBW23jdaOsdXJAOZu6gVD-eiMxWLpX_i9Hje2v6FhqDvetv_M1uutaPgCAZU34-QxmWLN2XK4MT0IaQdLK

It seems that the key size of the tenant is 1024 and 2048 is expected to use this.

So validating tenants again and Nick has a fairly new tenant in which I have an older tenant. I’ve used a separate tenant which is also new and presto it works out of the box there as well. Key size is 2048 and all is fine.

So with this information logged a GSS support case for this and turns out it’s indeed the case that new tenants will get a key size of 2048 and older tenants still have 1024. At this time there is no ETA on when older tenants will get upgraded. If you also want to log a support case and get some more traction reference HW-106923

Hope it helps!

Author: hheres

IT Pro / Geek