Finding ID | Version | Rule ID | IA Controls | Severity |
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V-75883 | UBTU-16-030580 | SV-90563r2_rule | Medium |
Description |
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Internet Control Message Protocol (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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Canonical Ubuntu 16.04 LTS Security Technical Implementation Guide | 2018-07-18 |
Check Text ( C-75571r2_chk ) |
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Verify the Ubuntu operating system does not allow interfaces to perform Internet Protocol version 4 (IPv4) Internet Control Message Protocol (ICMP) redirects by default. Check the value of the "default send_redirects" variables with the following command: # sudo sysctl 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-82513r2_fix) |
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Configure the Ubuntu operating system to not allow interfaces to perform Internet Protocol version 4 (IPv4) Internet Control Message Protocol (ICMP) redirects by default with the following command: # sudo sysctl -w net.ipv4.conf.default.send_redirects=0 If "0" is not the system's default value then add or update the following line in "/etc/sysctl.conf" or in the appropriate file under "/etc/sysctl.d": net.ipv4.conf.default.send_redirects=0 |