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Double Submit Cookies

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August 08, 2012
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Double Submit Cookies

An illustration of how the Double Submit Cookies method work in preventing Cross-Site Request Forgery

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szechuen

August 08, 2012
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Transcript

  1. Cookies   Double  Submit  Cookies   Web  Server   Client

      CSRF  Nonce   Session  ID   Form   CSRF  Nonce   Email  Add.  
  2. Cookies   Double  Submit  Cookies   Web  Server   Client

      CSRF  Nonce   Session  ID   Form   CSRF  Nonce   Email  Add.  
  3. Cookies   Double  Submit  Cookies   Web  Server   Client

      CSRF  Nonce   Session  ID   Form   CSRF  Nonce   [email protected]  
  4. Cookies   Double  Submit  Cookies   Web  Server   Client

      CSRF  Nonce   Session  ID   Form   CSRF  Nonce   [email protected]  
  5. Cookies   Double  Submit  Cookies   Web  Server   Client

      CSRF  Nonce   Session  ID   Form   CSRF  Nonce   [email protected]   Equal?  If  yes,  accept  form.  
  6. Cookies   Double  Submit  Cookies   Web  Server   Client

      CSRF  Nonce   Session  ID   Form   CSRF  Nonce   Email  Add.   A1acker  
  7. Cookies   Double  Submit  Cookies   Web  Server   Client

      CSRF  Nonce   Session  ID   A1acker  
  8. Cookies   Double  Submit  Cookies   Web  Server   Client

      CSRF  Nonce   Session  ID   Malicious  Form   Bad  Nonce   [email protected]   A1acker  
  9. Cookies   Double  Submit  Cookies   Web  Server   Client

      CSRF  Nonce   Session  ID   Malicious  Form   Bad  Nonce   [email protected]   A1acker  
  10. Double  Submit  Cookies   Web  Server   Client   A1acker

      Cookies   CSRF  Nonce   Session  ID   Malicious  Form   Bad  Nonce   [email protected]  
  11. Double  Submit  Cookies   Web  Server   Client   Equal?

     No:  Reject!   A1acker   Cookies   CSRF  Nonce   Session  ID   Malicious  Form   Bad  Nonce   [email protected]