Overview

Security Requirements for 03.13.13 Mobile Code

Mobile code technologies include Java, JavaScript, ActiveX, Postscript, PDF, Flash animations, and VBScript. Decisions regarding the use of mobile code in organizational systems are based on the potential for the code to cause damage to the systems if used maliciously. Usage restrictions and implementation guidance apply to the selection and use of mobile code installed on servers and mobile code downloaded and executed on individual workstations, notebook computers, and devices (e.g., smart phones). Mobile code policy and procedures address controlling or preventing the development, acquisition, or introduction of unacceptable mobile code in systems, including requiring mobile code to be digitally signed by a trusted source. [SP 800-28] provides guidance on mobile code.

Assessment GuidanceExamine 0/11

How an assessor determines this requirement is met. Source: CMMC Assessment Guide – Level 2, Version 2.13 (NIST SP 800-171 Rev. 2).

Discussion

Ensure mobile code is authorized to execute in company systems only in accordance with policy and technical configuration, and that unauthorized mobile code is not. Monitor the use of mobile code through boundary devices (e.g., firewalls), audit logs, or security utilities (e.g., mobile device management, advanced endpoint protection) and implement remediation activities as needed.

The first intent of this requirement is to ensure the limits of mobile code usage and usage restrictions are documented and enforced. This includes documenting all authorizations for the use of mobile code and ensuring it is not used in other ways. Usage restrictions and implementation guidance apply to the selection and use of mobile code installed on servers and mobile code downloaded and executed on individual workstations and devices to include all mobile devices and smart phones. The second intent is to monitor the use of mobile code and implement remediation steps if its use does not align with policy.

Examples

  1. Example 1

    Your company has decided to prohibit the use of Flash, ActiveX, and Java plug-ins for web browsers on all of its computers [a]. To enforce this policy you configure the computer baseline configuration to disable and deny the execution of mobile code [a]. You implement an exception process to re-enable mobile code execution only for those users with a legitimate business need [a].

  2. Example 2

    One department complains that a web application they need to perform their job no longer works. You meet with them and verify that the web application uses ActiveX in the browser. You submit a change request with the Change Review Board. Once the change is approved, you reconfigure the department’s computers to allow the running of ActiveX in the browser. You also configure the company firewall to alert you if ActiveX is used by any website but the allowed one [b]. You set a reminder for yourself to check in with the department at the end of the year to verify they still need that web application.

Assessment Methods

Examine
The process of reviewing, inspecting, observing, studying, or analyzing assessment objects (e.g., policies, procedures, plans, system designs, mechanisms) to facilitate understanding, achieve clarification, or obtain evidence.Example: An assessor reads the access control policy and inspects system configuration settings to confirm they match.

Not all of the evidence listed is required to meet this requirement — check the items your organization has collected.

Interview
The process of holding discussions with individuals or groups within an organization to facilitate understanding, achieve clarification, or identify the location of evidence.Example: An assessor asks a system administrator to describe how user accounts are approved, reviewed, and disabled.
  • System or network administrators
  • Personnel with information security responsibilities
  • Personnel with responsibilities for managing mobile code
Test
The process of exercising assessment objects (e.g., activities, mechanisms) under specified conditions to compare actual behavior with expected behavior.Example: An assessor attempts to sign in with a disabled account to confirm that access is denied.
  • Organizational process for controlling, authorizing, monitoring, and restricting mobile code
  • Mechanisms supporting or implementing the management of mobile code
  • Mechanisms supporting or implementing the monitoring of mobile code

Potential Assessment Considerations

  • Are there defined limits of mobile code usage and established usage restrictions, which specifically authorize use of mobile code (e.g., Java, JavaScript, ActiveX, PDF, Flash, Shockwave, Postscript, VBScript) within the information system [a]?
  • Is the use of mobile code documented, monitored, and managed (e.g., Java, JavaScript, ActiveX, PDF, Flash, Shockwave, Postscript, VBScript) [b]?

Key References

NIST SP 800-171 Rev. 2 3.13.13

Evidence

  1. 03.13.13.a

    Use of mobile code is controlled

  1. 03.13.13.b

    Use of mobile code is monitored