I have received an Audition on my network with possible weakness or vulnerability for an attack. The description is the follow:
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1033 ICMP netmask obtained
Risk Factor: Low
Complexity: Medium
Popularity: Obscure
Impact: Intelligence
Root Cause: Insecure Design
Ease of Fix: Moderate
Description: The netmask was obtained from the target host utilizing a capability present within the ICMP protocol. The ICMP protocol provides an operation to query a remote host for the network netmask.
Security Concerns: This information can assist an attacker in determining the internal structure of your network, as well as the routing scheme.
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I have suggestions to block ICMP and the issue is solved. I want know if exist other possibility to protect my network without block ICMP. My network have a Core router 7500 Series with 02 international links and others small routers directly connected to it.
Tx for the help
