CRV2 ClientSideCodeJSon

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JSON or JavaScript Object Notation is an open standard format that uses easy to read text to transmit data between a server and web applications. JSON data can be used by a large number of programming Languages and is becoming the de-facto standard in replacing XML.

JSON main security concern is JSON text dynamically embedded in JavaScript. This creates vulnerability in the program that may inadvertently to run a malicious script or store the malicious script to a database. This is a very real possibility when dealing with data retrieved from the Internet.

The code reviewer needs to make sure the JSON is not used with Javascript eval. Make sure JSON.parse(…) is used.

Var parsed_object = eval(“(“ + Jason_text  + “)”);  // Red flag for the code reviewer.
JSON.parse(text[, reviver]); .. // Much better then using javascript eval function.

Code reviewer should check to make sure the developer is not attempting to reject known bad patterns in text/string data, Using regex or other devices is fraught with error and makes testing for correctness very hard. Allow only whitelisted alphanumeric keywords and carefully validated numbers.

Do not allow JSON data to construct dynamic HTML. Always us safe DOM features like innerText or CreateTextNode(…)