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Input validation should be applied on both syntactical and Semantic level. Input Validation should not be used as the primary method of preventing XSS, SQL Injection and other attacks which are covered in respective cheat sheets but can significantly contribute to reducing their impact if implemented properly.
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Input validation should happen as early as possible in the data flow, preferably as soon as the data is received from the external party.ĭata from all potentially untrusted sources should be subject to input validation, including not only Internet-facing web clients but also backend feeds over extranets, from suppliers, partners, vendors or regulators, each of which may be compromised on their own and start sending malformed data. Input validation is performed to ensure only properly formed data is entering the workflow in an information system, preventing malformed data from persisting in the database and triggering malfunction of various downstream components. This article is focused on providing clear, simple, actionable guidance for providing Input Validation security functionality in your applications. Input Validation Cheat Sheet ¶ Introduction ¶ Insecure Direct Object Reference Prevention Preventing XSS and Content Security Policy