3.2.2 Ensure ICMP redirects are not accepted - 'net.ipv4.conf.all.accept_redirects = 0 /etc/sysctl.conf /etc/sysctl.d/*'

Information

Attackers could use bogus ICMP redirect messages to maliciously alter the system routing tables and get them to send packets to incorrect networks and allow your system packets to be captured.

Solution

Set the following parameters in the /etc/sysctl.conf file - net.ipv4.conf.all.accept_redirects = 0
net.ipv4.conf.default.accept_redirects = 0 Run the following commands to set the active kernel parameters - # sysctl -w net.ipv4.conf.all.accept_redirects=0
# sysctl -w net.ipv4.conf.default.accept_redirects=0
# sysctl -w net.ipv4.route.flush=1

See Also

https://workbench.cisecurity.org/files/1863

Item Details

Category: SYSTEM AND COMMUNICATIONS PROTECTION

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

Plugin: Unix

Control ID: d0e816cfa2d2bfea800e817ab9e9cd91373c3f6e5868b30fa2d5adf575965fcf