| Invalid input occurs when a user, or system acting on behalf of a user, inserts data or characters into an application's data entry fields and the application is unprepared to process that data. Checking the valid syntax and semantics of information system inputs (e.g., character set, length, numerical range, and acceptable values) verifies that inputs match specified definitions for format and content. Prescreening inputs prior to passing to interpreters prevent the content from being unintentionally interpreted as commands.
The integrity of the firewall ACL, rule sets, and security zone data is essential for controlling network access. Input validation helps ensure accurate and correct inputs and prevent attacks such as cross-site scripting and a variety of injection attacks. |
