cyberstrikeus 7.3.2 Disable IPv6 Redirect Acceptance (Not Scored)
Profile Applicability
- Level 1
Description
This setting prevents the system from accepting ICMP redirects. ICMP redirects tell the system about alternate routes for sending traffic.
Rationale
It is recommended that systems not accept ICMP redirects as they could be tricked into routing traffic to compromised machines. Setting hard routes within the system (usually a single default route to a trusted router) protects the system from bad routes.
Audit Procedure
Using Command Line
Perform the following to determine if IPv6 redirects are disabled.
/sbin/sysctl net.ipv6.conf.all.accept_redirects
/sbin/sysctl net.ipv6.conf.default.accept_redirects
Expected Result
net.ipv6.conf.all.accept_redirect = 0
net.ipv6.conf.default.accept_redirect = 0
Remediation
Using Command Line
Set the net.ipv6.conf.all.accept_redirects and net.ipv6.conf.default.accept_redirects parameters to 0 in /etc/sysctl.conf:
net.ipv6.conf.all.accept_redirects=0
net.ipv6.conf.default.accept_redirects=0
Modify active kernel parameters to match:
/sbin/sysctl -w net.ipv6.conf.all.accept_redirects=0
/sbin/sysctl -w net.ipv6.conf.default.accept_redirects=0
/sbin/sysctl -w net.ipv6.route.flush=1
Default Value
IPv6 redirect acceptance is enabled by default.
References
- CIS Ubuntu 12.04 LTS Server Benchmark v1.1.0
Profile
Level 1 - Not Scored