Level 5 CMMC - CMMC Practices

SI.1.213  

Reference: CMMC 1.02

Family: SI

Level Introduced: 1

Practice:
Perform periodic scans of the information system and real-time scans of files from external sources as files are downloaded, opened, or executed.

CMMC Clarification:
Companies should use anti-malware software to scan and identify viruses in their computer systems, and have a plan for how often scans are conducted. Real-time scans will look at the system whenever new files are downloaded, opened, and saved. Periodic scans check previously saved files against updated malware information.

Example
While cleaning up your office, you find your old thumb drive. You are not sure if you should use it. Then you remember something: Your company just purchased anti-malware software that auto-updates with the latest antivirus code and definitions of all known malware. With this in mind, you decide to plug in the thumb drive. The new anti-malware software scans the thumb drive, finds a virus, then deletes the file.

3.14.5

Perform periodic scans of organizational systems and real-time scans of files from external sources as files are downloaded, opened, or executed.

Discussion:
Periodic scans of organizational systems and real-time scans of files from external sources can detect malicious code. Malicious code can be encoded in various formats (e.g., UUENCODE, Unicode), contained within compressed or hidden files, or hidden in files using techniques such as steganography. Malicious code can be inserted into systems in a variety of ways including web accesses, electronic mail, electronic mail attachments, and portable storage devices. Malicious code insertions occur through the exploitation of system vulnerabilities.

Source: NIST Special Publication 800-171 Rev. 2

SI-3

MALICIOUS CODE PROTECTION

Description:
The organization:
    a. Employs malicious code protection mechanisms at information system entry and exit points to detect and eradicate malicious code;
    b. Updates malicious code protection mechanisms whenever new releases are available in accordance with organizational configuration management policy and procedures;
    c. Configures malicious code protection mechanisms to:
        1. Perform periodic scans of the information system [Assignment: organization-defined frequency] and real-time scans of files from external sources at [Selection (one or more); endpoint; network entry/exit points] as the files are downloaded, opened, or executed in accordance with organizational security policy; and
        2. [Selection (one or more): block malicious code; quarantine malicious code; send alert to administrator; [Assignment: organization-defined action]] in response to malicious code detection; and
    d. Addresses the receipt of false positives during malicious code detection and eradication and the resulting potential impact on the availability of the information system.

Supplemental Guidance:
Information system entry and exit points include, for example, firewalls, electronic mail servers, web servers, proxy servers, remote-access servers, workstations, notebook computers, and mobile devices. Malicious code includes, for example, viruses, worms, Trojan horses, and spyware. Malicious code can also be encoded in various formats (e.g., UUENCODE, Unicode), contained within compressed or hidden files, or hidden in files using steganography. Malicious code can be transported by different means including, for example, web accesses, electronic mail, electronic mail attachments, and portable storage devices. Malicious code insertions occur through the exploitation of information system vulnerabilities. Malicious code protection mechanisms include, for example, anti-virus signature definitions and reputation-based technologies. A variety of technologies and methods exist to limit or eliminate the effects of malicious code. Pervasive configuration management and comprehensive software integrity controls may be effective in preventing execution of unauthorized code. In addition to commercial off-the-shelf software, malicious code may also be present in custom-built software. This could include, for example, logic bombs, back doors, and other types of cyber attacks that could affect organizational missions/business functions. Traditional malicious code protection mechanisms cannot always detect such code. In these situations, organizations rely instead on other safeguards including, for example, secure coding practices, configuration management and control, trusted procurement processes, and monitoring practices to help ensure that software does not perform functions other than the functions intended. Organizations may determine that in response to the detection of malicious code, different actions may be warranted. For example, organizations can define actions in response to malicious code detection during periodic scans, actions in response to detection of malicious downloads, and/or actions in response to detection of maliciousness when attempting to open or execute files. Related controls: CM-3, MP-2, SA-4, SA-8, SA-12, SA-13, SC-7, SC-26, SC-44, SI-2, SI-4, SI-7.

Source: NIST Special Publication 800-53 Rev. 4

Source: CMMC v1.02