This does not mean that other users cannot access this mailbox, for example when the user makes use of a service that generates a throw away email address.
As the local-part of email addresses are, in fact - case sensitive, it is important to store and compare email addresses correctly.
In summary, input validation should: Example validating the parameter “zip” using a regular expression.
private static final Pattern zip Pattern = Pattern.compile("^\d(-\d)?
It is always recommended to prevent attacks as early as possible in the processing of the user’s (attacker's) request.
Input validation can be used to detect unauthorized input before it is processed by the application.
Recent changes to the landscape mean that the number of false-negatives will increase, particularly due to: To ensure an address is deliverable, the only way to check this is to send the user an email and have the user take action to confirm receipt.
Beyond confirming that the email address is valid and deliverable, this also provides a positive acknowledgement that the user has access to the mailbox and is likely to be authorized to use it.Data 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 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.$"); 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.Ensure that any input validation performed on the client is also performed on the server.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.