Tuesday, April 22

How to avoid CSRF - Cross Side Request Forgery attack

How to prevent CSRF using.

CSRF attack can be prevented using Synchronized Token Pattern.

When an HTML form is rendered ,server assigns it a unique and random identifier in the form of hidden http parameter. Server

Also stored the unique identifier in user session profile

When This form is submitted server compares the identifier's value in hidden field with value stored in user session profile . If value matches only then request is further processed otherwise request is aborted.

Thus if any evil website tries to submit a form with forging the client request information in that , it is not able to generate the unique identifier As
It does not know How to get it , It's not there on client cookie , it's not guessable . So attacker can't make CSRF attack.

For example : If a form named businessForm is rendered is follow ,server creates random token and form store that in hidden field. Also it's value is sotred
in user session



When user submit this form token value is validated. Evil site can't steal this random number So that request will be rejected and CSRF attack will be prevented

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