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.Input validation should be applied on both syntactical and semantic level.Specifically, it is completely valid to have an mailbox address which: At the time of writing, RFC 5321 is the current standard defining SMTP and what constitutes a valid mailbox address.Please note, email addresses should be considered to be public data.For more information, please see the cheatsheet on Sanitizing HTML Markup with a Library Designed for the Job.Detailed information on XSS prevention here: OWASP XSS Prevention Cheat Sheet Many websites allow users to upload files, such as a profile picture or more. Many web applications do not treat email addresses correctly due to common misconceptions about what constitutes a valid address.Many web applications contain computationally expensive and inaccurate regular expressions that attempt to validate email addresses.
To normalise an email address input, you would convert the domain part ONLY to lowercase.
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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.
private static final Pattern zip Pattern = Pattern.compile("^\d(-\d)?
$"); public void do Post( Http Servlet Request request, Http Servlet Response response) Be aware that any Java Script input validation performed on the client can be bypassed by an attacker that disables Java Script or uses a Web Proxy.
start date is before end date, price is within expected range).