7: Email and Web Browser Protections
PF v1.0 References:
Threats Addressed:
Control Statement
Minimize the attack surface and the opportunities for attackers to manipulate human behavior though their interaction with web browsers and email systems.
[csf.tools Note: For more information on the Critical Security Controls, visit the Center for Internet Security.]
Subcontrols
7.1: Ensure Use of Only Fully Supported Browsers and Email Clients
Ensure that only fully supported web browsers and email clients are allowed to execute in the organization, ideally only using the latest version of the browsers and email clients provided by the vendor.
7.2: Disable Unnecessary or Unauthorized Browser or Email Client Plugins
Uninstall or disable any unauthorized browser or email client plugins or add-on applications.
7.3: Limit Use of Scripting Languages in Web Browsers and Email Clients
Ensure that only authorized scripting languages are able to run in all web browsers and email clients.
7.4: Maintain and Enforce Network-Based URL Filters
Enforce network-based URL filters that limit a system's ability to connect to websites not approved by the organization. This filtering shall be enforced for each of the organization's systems, whether they are physically at an organization's facilities or not.
7.5: Subscribe to URL-Categorization Service
Subscribe to URL-categorization services to ensure that they are up-to-date with the most recent website category definitions available. Uncategorized sites shall be blocked by default.
7.6: Log All URL requester
Log all URL requests from each of the organization's systems, whether on-site or a mobile device, in order to identify potentially malicious activity and assist incident handlers with identifying potentially compromised systems.
7.7: Use of DNS Filtering Services
Use Domain Name System (DNS) filtering services to help block access to known malicious domains.
7.8: Implement DMARC and Enable Receiver-Side Verification
To lower the chance of spoofed or modified emails from valid domains, implement Domain-based Message Authentication, Reporting and Conformance (DMARC) policy and verification, starting by implementing the Sender Policy Framework (SPF) and the DomainKeys Identified Mail(DKIM) standards.
7.9: Block Unnecessary File Types
Block all email attachments entering the organization's email gateway if the file types are unnecessary for the organization's business.
7.10: Sandbox All Email Attachments
Use sandboxing to analyze and block inbound email attachments with malicious behavior.