7.2.3 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

Modify active kernel parameters to match-# /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

See Also

https://workbench.cisecurity.org/files/91

Item Details

Category: SYSTEM AND COMMUNICATIONS PROTECTION

References: 800-53|SC-7(12), CSCv6|9.2

Plugin: Unix

Control ID: 69616a306fbc93f3430776b0c707597ea1847e8d52c6bb92866bb964a061c9b4