SI-10: Information Input Validation
Control Family:
Threats Addressed:
Baselines:
- Low
N/A
- Moderate
- SI-10
- High
- SI-10
Next Version:
- NIST Special Publication 800-53 Revision 5:
- SI-10: Information Input Validation
Control Statement
The information system checks the validity of [Assignment: organization-defined information inputs].
Supplemental Guidance
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. Software applications typically follow well-defined protocols that use structured messages (i.e., commands or queries) to communicate between software modules or system components. Structured messages can contain raw or unstructured data interspersed with metadata or control information. If software applications use attacker-supplied inputs to construct structured messages without properly encoding such messages, then the attacker could insert malicious commands or special characters that can cause the data to be interpreted as control information or metadata. Consequently, the module or component that receives the tainted output will perform the wrong operations or otherwise interpret the data incorrectly. Prescreening inputs prior to passing to interpreters prevents the content from being unintentionally interpreted as commands. Input validation helps to ensure accurate and correct inputs and prevent attacks such as cross-site scripting and a variety of injection attacks.
Control Enhancements
SI-10(1): Manual Override Capability
Baseline(s):
The information system: Provides a manual override capability for input validation of [Assignment: organization-defined inputs]; Restricts the use of the manual override capability to only [Assignment: organization-defined authorized individuals]; and Audits the use of the manual override capability.
SI-10(2): Review / Resolution Of Errors
Baseline(s):
The organization ensures that input validation errors are reviewed and resolved within [Assignment: organization-defined time period].
SI-10(3): Predictable Behavior
Baseline(s):
The information system behaves in a predictable and documented manner that reflects organizational and system objectives when invalid inputs are received.
SI-10(4): Review / Timing Interactions
Baseline(s):
The organization accounts for timing interactions among information system components in determining appropriate responses for invalid inputs.
SI-10(5): Restrict Inputs To Trusted Sources And Approved Formats
Baseline(s):
The organization restricts the use of information inputs to [Assignment: organization-defined trusted sources] and/or [Assignment: organization-defined formats].