Information
Secure ICMP redirects are the same as ICMP redirects, except they come from gateways
listed on the default gateway list. It is assumed that these gateways are known to your
system, and that they are likely to be secure.
Rationale:
It is still possible for even known gateways to be compromised. Setting
net.ipv4.conf.all.secure_redirects to 0 protects the system from routing table
updates by possibly compromised known gateways.
Solution
Set the following parameters in /etc/sysctl.conf or a /etc/sysctl.d/* file:
net.ipv4.conf.all.secure_redirects = 0
net.ipv4.conf.default.secure_redirects = 0
Run the following commands to set the active kernel parameters:
# sysctl -w net.ipv4.conf.all.secure_redirects=0
# sysctl -w net.ipv4.conf.default.secure_redirects=0
# sysctl -w net.ipv4.route.flush=1