|SI-10 (1) Manual Override Capability || |
The information system: SI-10 (1)(a)
Provides a manual override capability for input validation of Assignment: organization-defined inputs; SI-10 (1)(b)
Restricts the use of the manual override capability to only Assignment: organization-defined authorized individuals; and SI-10 (1)(c)
Audits the use of the manual override capability.
|SI-10 (2) Review / Resolution Of Errors || |
Resolution of input validation errors includes, for example, correcting systemic causes of errors and resubmitting transactions with corrected input.
The organization ensures that input validation errors are reviewed and resolved within Assignment: organization-defined time period.
|SI-10 (3) Predictable Behavior || |
A common vulnerability in organizational information systems is unpredictable behavior when invalid inputs are received. This control enhancement ensures that there is predictable behavior in the face of invalid inputs by specifying information system responses that facilitate transitioning the system to known states without adverse, unintended side effects.
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 || |
In addressing invalid information system inputs received across protocol interfaces, timing interfaces become relevant, where one protocol needs to consider the impact of the error response on other protocols within 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 collisions or noise on the link. If TCP makes a congestion response, it takes precisely the wrong action in response to a collision event. Adversaries may be able to use apparently acceptable individual behaviors of the protocols in concert to achieve adverse effects through suitable construction of invalid input.
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 || |
This control enhancement applies the concept of whitelisting to information inputs. Specifying known trusted sources for information inputs and acceptable formats for such inputs can reduce the probability of malicious activity.
The organization restricts the use of information inputs to Assignment: organization-defined trusted sources and/or Assignment: organization-defined formats.