+SI-10 Information Input Validation
---+SI-10(01) Manual Override Capability
---+SI-10(02) Review and Resolve Errors
---+SI-10(03) Predictable Behavior
---+SI-10(04) Timing Interactions
---+SI-10(05) Restrict Inputs to Trusted Sources and Approved Formats
---+SI-10(06) Injection Prevention

SI-10 Information Input Validation

Control

Check the validity of the following information inputs: [Assignement: information inputs].

Discussion

Checking the valid syntax and semantics of system inputs—including character set, length, numerical range, and acceptable values—verifies that inputs match specified definitions for format and content. For example, if the organization specifies that numerical values between 1-100 are the only acceptable inputs for a field in a given application, inputs of "387," "abc," or "%K%" are invalid inputs and are not accepted as input to the system. Valid inputs are likely to vary from field to field within a software application. 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 corrupted output will perform the wrong operations or otherwise interpret the data incorrectly. Prescreening inputs prior to passing them to interpreters prevents the content from being unintentionally interpreted as commands. Input validation ensures accurate and correct inputs and prevents attacks such as cross-site scripting and a variety of injection attacks.

Assessment Objective

the validity of the [Assignement: information inputs] is checked.

Assessment Method

Examine

System and information integrity policy system and information integrity procedures access control policy and procedures separation of duties policy and procedures procedures addressing information input validation documentation for automated tools and applications to verify the validity of information list of information inputs requiring validity checks system design documentation system configuration settings and associated documentation system audit records system security plan other relevant documents or records

Interview

Organizational personnel responsible for information input validation organizational personnel with information security responsibilities system/network administrators system developer

1. Přehled

Název	Standard
SI-10(01) Manual Override Capability	Control Provide a manual override capability for input validation of the following information inputs: [Assignement: information inputs]; Restrict the use of the manual override capability to only [Assignement: authorized individuals] ; and Audit the use of the manual override capability. Discussion In certain situations, such as during events that are defined in contingency plans, a manual override capability for input validation may be needed. Manual overrides are used only in limited circumstances and with the inputs defined by the organization. Assessment Objective a manual override capability for the validation of [Assignement: information inputs] is provided; the use of the manual override capability is restricted to only [Assignement: authorized individuals]; the use of the manual override capability is audited. Assessment Method Examine System and information integrity policy system and information integrity procedures access control policy and procedures separation of duties policy and procedures procedures addressing information input validation system design documentation system configuration settings and associated documentation system audit records system security plan other relevant documents or records Interview Organizational personnel responsible for information input validation organizational personnel with information security responsibilities system/network administrators system developer
SI-10(02) Review and Resolve Errors	Control Review and resolve input validation errors within [Assignement: organization-defined time period]. Discussion Resolution of input validation errors includes correcting systemic causes of errors and resubmitting transactions with corrected input. Input validation errors are those related to the information inputs defined by the organization in the base control ( [SI-10](#si-10)). Assessment Objective input validation errors are reviewed within [Assignement: time period]; input validation errors are resolved within [Assignement: time period]. Assessment Method Examine System and information integrity policy system and information integrity procedures procedures addressing information input validation system design documentation system configuration settings and associated documentation review records of information input validation errors and resulting resolutions information input validation error logs or records system audit records system security plan other relevant documents or records Interview Organizational personnel responsible for information input validation organizational personnel with information security responsibilities system/network administrators
SI-10(03) Predictable Behavior	Control Verify that the system behaves in a predictable and documented manner when invalid inputs are received. Discussion A common vulnerability in organizational systems is unpredictable behavior when invalid inputs are received. Verification of system predictability helps ensure that the system behaves as expected when invalid inputs are received. This occurs by specifying system responses that allow the system to transition to known states without adverse, unintended side effects. The invalid inputs are those related to the information inputs defined by the organization in the base control ( [SI-10](#si-10)). Assessment Objective the system behaves in a predictable manner when invalid inputs are received; the system behaves in a documented manner when invalid inputs are received. Assessment Method Examine System and information integrity policy system and information integrity procedures procedures addressing information input validation system design documentation system configuration settings and associated documentation system audit records system security plan other relevant documents or records Interview Organizational personnel responsible for information input validation organizational personnel with information security responsibilities system/network administrators system developer
SI-10(04) Timing Interactions	Control Account for timing interactions among system components in determining appropriate responses for invalid inputs. Discussion In addressing invalid system inputs received across protocol interfaces, timing interactions become relevant, where one protocol needs to consider the impact of the error response on other protocols in the protocol stack. For example, 802.11 standard wireless network protocols do not interact well with Transmission Control Protocols (TCP) when packets are dropped (which could be due to invalid packet input). TCP assumes packet losses are due to congestion, while packets lost over 802.11 links are typically dropped due to noise or collisions on the link. If TCP makes a congestion response, it takes the wrong action in response to a collision event. Adversaries may be able to use what appear to be acceptable individual behaviors of the protocols in concert to achieve adverse effects through suitable construction of invalid input. The invalid inputs are those related to the information inputs defined by the organization in the base control ( [SI-10](#si-10)). Assessment Objective timing interactions among system components are accounted for in determining appropriate responses for invalid inputs. Assessment Method Examine System and information integrity policy system and information integrity procedures procedures addressing information input validation system design documentation system configuration settings and associated documentation system audit records system security plan other relevant documents or records Interview Organizational personnel responsible for information input validation organizational personnel with information security responsibilities system/network administrators system developer
SI-10(05) Restrict Inputs to Trusted Sources and Approved Formats	Control Restrict the use of information inputs to [Assignement: trusted sources] and/or [Assignement: formats]. Discussion Restricting the use of inputs to trusted sources and in trusted formats applies the concept of authorized or permitted software to information inputs. Specifying known trusted sources for information inputs and acceptable formats for such inputs can reduce the probability of malicious activity. The information inputs are those defined by the organization in the base control ( [SI-10](#si-10)). Assessment Objective the use of information inputs is restricted to [Assignement: trusted sources] and/or [Assignement: formats]. Assessment Method Examine System and information integrity policy system and information integrity procedures procedures addressing information input validation system design documentation system configuration settings and associated documentation list of trusted sources for information inputs list of acceptable formats for input restrictions system audit records system security plan other relevant documents or records Interview Organizational personnel responsible for information input validation organizational personnel with information security responsibilities system/network administrators system developer
SI-10(06) Injection Prevention	Control Prevent untrusted data injections. Discussion Untrusted data injections may be prevented using a parameterized interface or output escaping (output encoding). Parameterized interfaces separate data from code so that injections of malicious or unintended data cannot change the semantics of commands being sent. Output escaping uses specified characters to inform the interpreter’s parser whether data is trusted. Prevention of untrusted data injections are with respect to the information inputs defined by the organization in the base control ( [SI-10](#si-10)). Assessment Objective untrusted data injections are prevented. Assessment Method Examine System and information integrity policy system and information integrity procedures procedures addressing information input validation system design documentation system configuration settings and associated documentation list of trusted sources for information inputs list of acceptable formats for input restrictions system audit records system security plan other relevant documents or records Interview Organizational personnel responsible for information input validation organizational personnel with information security responsibilities system/network administrators system developer

1.1 Odkazy

1.2 Identifikované požadavky

1.3 Související regulace

2. Identifikované požadavky

Požadavky
Zdroj	Požadavek

3. Související regulace

Regulace
Zdroj	Regulace

Propojené úkoly

Vazby
Typ vazby	Úkol
is blocked by	SI-10 Information Input Validation – Assessment Procedure
is blocked by	Safeguarding Data Over Open Networks
is blocked by	Input Data Validation

NIST -
https://csrc.nist.gov/pubs/sp/800/53/r5/upd1/final