4.2.3 Disable Secure ICMP Redirect Acceptance - net.ipv4.conf.default.secure_redirects = 0

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 net.ipv4.conf.all.secure_redirects and net.ipv4.conf.default.secure_redirects parameters to 0 in /etc/sysctl.conf:

net.ipv4.conf.all.secure_redirects=0
net.ipv4.conf.default.secure_redirects=0

Run the following commands to set the active kernel parameters:

# /sbin/sysctl -w net.ipv4.conf.all.secure_redirects=0
# /sbin/sysctl -w net.ipv4.conf.default.secure_redirects=0
# /sbin/sysctl -w net.ipv4.route.flush=1




Default Value:

OS Default: No

See Also

https://workbench.cisecurity.org/files/3096

Item Details

Category: SYSTEM AND INFORMATION INTEGRITY

References: 800-53|SI-4, CSCv6|9.2, CSCv7|9.2

Plugin: Unix

Control ID: 9d2614ca5bd5bcdd5b3cae19f3c9b6d9c34ea050835f5f52626351e4aa429098