Finding ID | Version | Rule ID | IA Controls | Severity |
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V-81805 | SLES-12-030401 | SV-96519r1_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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SLES 12 Security Technical Implementation Guide | 2020-06-30 |
Check Text ( C-81599r1_chk ) |
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Verify the SUSE operating system does not allow IPv6 ICMP redirect messages by default. 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", this is a finding. |
Fix Text (F-88657r1_fix) |
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Configure the SUSE operating system to not allow IPv6 ICMP redirect messages 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.ipv6.conf.default.accept_redirects=0 Run the following command to apply this value: # sysctl –system |