On 6/29/12 5:45 PM, Willy Santos wrote:
CCI-000025 refers to enforcing information flow control based on explicit security attributes. This mapping is open to discussion and change.

SRG-OS-000009 CCI-000025 The operating system must enforce information flow control using explicit security attributes on information, source, and destination objects as a basis for flow control decisions. Information flow control regulates where information is allowed to travel within an information system and between information systems (as opposed to who is allowed to access the information) and without explicit regard to subsequent accesses to the information. Examples of flow control restrictions include: keeping export controlled information from being transmitted in the clear to the Internet; and blocking outside traffic claiming to be from within the organization and not passing any web requests to the Internet that are not from the internal web proxy. Information flow control policies and enforcement mechanisms are commonly employed by organizations to control the flow of information between designated sources and destinations (e.g., networks, individuals, devices) within information systems and between interconnected systems. Flow control is based on the characteristics of the information and/or the information path. Information flow enforcement mechanisms compare security attributes on all information (data content and data structure), source and destination objects, and respond appropriately (e.g., block, quarantine, alert administrator) when the mechanisms encounter information flows not explicitly allowed by the information flow policy. Information flow enforcement using explicit security attributes can be used, for example, to control the release of certain types of information.

Source and destination are easy -- IPTables. It's when "security attributes" come into play that I get caught up. Technically we can enforce this by mandating MCS or MLS enablement. This requirement makes sense if we were to make a CNSS 12-53 profile, but I'm not convinced this makes sense for a general purpose security guide.

 unmet_impractical_guidance in my opinion