The Cisco switch must be configured to have Internet Control Message Protocol (ICMP) mask reply messages disabled on all external interfaces.
An XCCDF Rule
Description
The ICMP supports IP traffic by relaying information about paths, routes, and network conditions. Switches 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-220434r856236_rule
- Version
- CISC-RT-000180
- Severity
- Medium
- References
- Updated
Remediation Templates
A Manual Procedure
Disable ip mask-reply on all external interfaces as shown below:
SW1(config)#int g0/1
SW1(config-if)#no ip mask-reply