Finding ID | Version | Rule ID | IA Controls | Severity |
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V-72291 | RHEL-07-040650 | SV-86915r3_rule | Medium |
Description |
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ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages contain information from the system's route table, possibly revealing portions of the network topology. |
STIG | Date |
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Red Hat Enterprise Linux 7 Security Technical Implementation Guide | 2017-12-14 |
Check Text ( C-72525r3_chk ) |
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Verify the system does not allow interfaces to perform IPv4 ICMP redirects by default. Check the value of the "default send_redirects" variables with the following command: # /sbin/sysctl -a | grep 'net.ipv4.conf.default.send_redirects' net.ipv4.conf.default.send_redirects = 0 If the returned line does not have a value of "0", or a line is not returned, this is a finding. |
Fix Text (F-78645r3_fix) |
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Configure the system to not allow interfaces to perform IPv4 ICMP redirects by default. Set the system to the required kernel parameter by adding the following line to "/etc/sysctl.conf" (or modify the line to have the required value): net.ipv4.conf.default.send_redirects=0 Issue the following command to make the changes take effect: # sysctl -p /etc/sysctl.conf |