SI-3 Malicious Code Protection (L) (M) (H)

NIST 800-53 (r4) Control:

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 [FedRAMP Assignment: (L)(M)(H) at least weekly] and real-time scans of files from external sources at [FedRAMP Assignment: (L)(M)(H) to include endpoints] as the files are downloaded, opened, or executed in accordance with organizational security policy; and

2. [FedRAMP Assignment: (L)(M) to include alerting administrator or defined security personnel; (H) to include blocking and quarantining malicious code and alerting administrator or defined security personnel near-real time] 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.

NIST 800-53 (r4) 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.

References: NIST Special Publication 800-83.

NIST 800-53 (r5) Discussion:

System entry and exit points include firewalls, remote access servers, workstations, electronic mail servers, web servers, proxy servers, notebook computers, and mobile devices. Malicious code includes viruses, worms, Trojan horses, and spyware. Malicious code can also be encoded in various formats 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 by electronic mail, the world-wide web, and portable storage devices. Malicious code insertions occur through the exploitation of system vulnerabilities. A variety of technologies and methods exist to limit or eliminate the effects of malicious code.

Malicious code protection mechanisms include both signature- and nonsignature-based technologies. Nonsignature-based detection mechanisms include artificial intelligence techniques that use heuristics to detect, analyze, and describe the characteristics or behavior of malicious code and to provide controls against such code for which signatures do not yet exist or for which existing signatures may not be effective. Malicious code for which active signatures do not yet exist or may be ineffective includes polymorphic malicious code (i.e., code that changes signatures when it replicates). Nonsignature-based mechanisms also include reputation-based technologies. In addition to the above technologies, pervasive configuration management, comprehensive software integrity controls, and anti-exploitation software may be effective in preventing the execution of unauthorized code. Malicious code may be present in commercial off-the-shelf software as well as custom-built software and could include logic bombs, backdoors, and other types of attacks that could affect organizational mission and business functions.

In situations where malicious code cannot be detected by detection methods or technologies, organizations rely on other types of controls, including secure coding practices, configuration management and control, trusted procurement processes, and monitoring practices to 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, the detection of malicious downloads, or the detection of maliciousness when attempting to open or execute files.

38North Guidance:

Meets Minimum Requirement:

• Part a. Deploy malicious code protection mechanisms (i.e., antivirus) at information system entry and exit points to detect and eradicate malicious code. Ensure antivirus is installed on the operating systems for the servers themselves, can exclude network devices.

• Part b. Once deployed, update malicious code protection mechanisms whenever new releases are available in accordance with organizational configuration management policy and procedures.

• Part c. Configure malicious code protection mechanisms to:

  • 1. Perform periodic scans at least weekly and real-time scans of files from external sources at endpoints as the files are downloaded, opened, or executed; and

    2. (H) Block malicious code; quarantine malicious code; and (L)(M)(H) send alerts to administrator or defined security personnel in response to malicious code detection (H) near-real time.

• Part d. Review alerts to mitigate the possibility of false positives disrupting the information system. False positives must be analyzed as they occur and they must be excluded so system availability is not affected in the future.

Best Practice:

• Typical antivirus solutions include McAfee, ClamAV, Carbon Black, Trend Micro Deep Security, etc.

Unofficial FedRAMP Guidance: None

Assessment Evidence:

• Part a. Configuration showing antivirus is installed on appropriate system components (Operating Systems).

• Part b. Configuration showing antivirus is updated whenever new releases are available (i.e., signature schedule).

• Part c. Configuration showing antivirus scan settings (i.e., scan schedule) and associated antivirus alerts.

• Part d. False positives that have been addressed and any resulting impacts to the availability of the system.

CSP Implementation Tips: None