Finding ID | Version | Rule ID | IA Controls | Severity |
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V-248876 | OL08-00-040210 | SV-248876r780194_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 modify the host's route table and are unauthenticated. An illicit ICMP redirect message could result in a man-in-the-middle attack. |
STIG | Date |
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Oracle Linux 8 Security Technical Implementation Guide | 2021-07-21 |
Check Text ( C-52310r780192_chk ) |
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Verify OL 8 will not accept IPv6 ICMP redirect messages. Note: IPv6 is disabled on the system, this requirement is Not Applicable. Check the value of the default "accept_redirects" variables with the following command: $ sudo sysctl net.ipv6.conf.default.accept_redirects net.ipv6.conf.default.accept_redirects = 0 If the returned line does not have a value of "0", a line is not returned, or the line is commented out, this is a finding. |
Fix Text (F-52264r780193_fix) |
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Configure OL 8 to prevent IPv6 ICMP redirect messages from being accepted with the following command: $ sudo sysctl -w net.ipv6.conf.default.accept_redirects=0 If "0" is not the system's default value, add or update the following line in "/etc/sysctl.conf" or in the appropriate file under "/etc/sysctl.d": net.ipv6.conf.default.accept_redirects=0 |