SI.L1-b.1.xv
System & File Scanning [FCI Data]
Source and approval
CMMC Assessment Guide — Level 1 · Revision 2.13
Publisher approved · Complete cited source edition 2026-10-31
Read the official guideSee SI.L1-b.1.xv in the reference catalog with its NIST cross-references
Official requirement
Perform periodic scans of the information system and real-time scans of files from external sources as files are downloaded, opened, or executed.
Assessment objectives
a. the frequency for malicious code scans is defined;
b. malicious code scans are performed with the defined frequency; and
c. real-time malicious code scans of files from external sources as files are downloaded, opened, or executed are performed.
Implementation guidance
Editorial examples to help you plan. Adapt them to your environment; the official requirement and objectives remain authoritative.
In plain language
Run periodic system scans and real-time scans of files arriving from external sources.
Implementation example
Example from the source assessment guide (not a mandatory implementation): Your company transmits FCI over email. You work with your company’s email provider to enable enhanced protections that will scan all attachments to identify and quarantine those that may be harmful prior to a user opening them [c]. In addition, you configure antivirus software on each computer to scan for malicious code every day [a,b]. The software also scans files that are downloaded or copied from removable media such as USB drives. It quarantines any suspicious files and notifies the security team [c].
Evidence examples
Examples suggested by the source guide (not an exhaustive or mandatory checklist): System and information integrity policy; configuration management policy and procedures; procedures addressi ng malicious code protection; malicious code protection mechanisms; records of malicious code protection updates; system security plan; system design documentation; system configuration settings and associated documentation; scan results from malicious cod e protection mechanisms; record of actions initiated by malicious code protection mechanisms in response to malicious code detection; system audit logs and records; other relevant documents or records
Common mistakes
Relying only on a periodic scan while leaving downloads or other external files unscanned.