AWS cognito-idp: Get client Authentic Tokens

Require info

user_name  : client_cog-idp@hogemail.com
password   : mypassword-hogehoge
client_ID  : 0123456789abcdef0123456789
userpool_ID: ap-northeast-1_aBCDEFG89

• client_ID consist of 26 chars
• userpool_ID consist of <aws_region>_<unique_service_ID>
• <aws_region> is ap-northeast-1 in japan. AWS: Regions and Availability Zones
• <unique_service_ID> is consist of 9 chars

I want to know userpool_ID and/or client_ID !

• I'm an AWS user: Look AWS Web page
• I'm a not AWS user (mean I'm a user of services using AWS): Have you an account? Let's capture the packet!

---

Capture the packet

Use some capturing tool. e.g) Wireshark, Burp Suite or etc.
And login tha service.

target: https;/cognito-idp.<aws_region>.amazon.com

client_ID is in there.
userpool_ID is ecrypted.

Decode the value by base64 in any reply:

{"AuthenticationResult":
{"AccessToken":"4LTYhFhn....SJIg",
"ExpiresIn":3600,
"IdToken":"ZWF.E1Fb....KCB",
"RefreshToken":"sEMhD.N....6Hp3mhze"..