The router must be configured to have Internet Control Message Protocol (ICMP) mask replies disabled on all external interfaces.
An XCCDF Rule
Description
The ICMP supports IP traffic by relaying information about paths, routes, and network conditions. Routers automatically send ICMP messages under a wide variety of conditions. Mask Reply ICMP messages are commonly used by attackers for network mapping and diagnosis.
- ID
- SV-207154r856638_rule
- Version
- SRG-NET-000362-RTR-000114
- Severity
- Medium
- References
- Updated
Remediation Templates
A Manual Procedure
Disable ICMP mask replies on all external interfaces.