7.1.2 Disable Send Packet Redirects - net.ipv4.conf.default.send_redirects

Information

ICMP Redirects are used to send routing information to other hosts. As a host itself does not act as a router (in a host only configuration), there is no need to send redirects. An attacker could use a compromised host to send invalid ICMP redirects to other router devices in an attempt to corrupt routing and have users access a system set up by the attacker as opposed to a valid system.

Solution

Set the net.ipv4.conf.all.send_redirects and net.ipv4.conf.default.send_redirects parameters to 0 in /etc/sysctl.conf- net.ipv4.conf.all.send_redirects=0net.ipv4.conf.default.send_redirects=0 Modify active kernel parameters to match- # /sbin/sysctl -w net.ipv4.conf.all.send_redirects=0# /sbin/sysctl -w net.ipv4.conf.default.send_redirects=0# /sbin/sysctl -w net.ipv4.route.flush=1

See Also

https://workbench.cisecurity.org/files/85

Item Details

Category: SYSTEM AND COMMUNICATIONS PROTECTION

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

Plugin: Unix

Control ID: 27e8acf92010599cedea3938acbb0c9c3a164395047aec499221bff7462b0da4