Perform periodic scans of the information system and real-time scans of files from external sources as files are downloaded, opened, or executed.
DiscussionPeriodic 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.
Further DiscussionConsider use anti-malware software to scan for viruses in your computer systems and determine how often scans are conducted. Real-time scans look at the system whenever files are downloaded, opened, and saved. Periodic scans check previously saved files against updated malware information.
ExampleYour 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].
Potential Assessment Considerations
- Are files from media (e.g., USB drives, CD-ROM) included in the definition of external sources and are they being scanned [c]?