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RHEL-10-800160 RHEL 10 must use a reverse-path filter for Internet Protocol version 4 (IPv4) network traffic when possible by default.

DISA STIG library V1R3
All changes in this version
first version loaded CAT II

Maps to SC-5, SC-7(4) via CCI-002385, CCI-001103

Title

RHEL 10 must use a reverse-path filter for Internet Protocol version 4 (IPv4) network traffic when possible by default.

Control

Verify RHEL 10 uses reverse path filtering on IPv4 interfaces. Check the value of the "net.ipv4.conf.default.rp_filter" with the following command: $ sudo sysctl net.ipv4.conf.default.rp_filter net.ipv4.conf.default.rp_filter = 1 If the returned line does not have a value of "1", or a line is not returned, this is a finding.

Discussion

Enabling reverse path filtering drops packets with source addresses that should not have been able to be received on the interface on which they were received. It must not be used on systems that are routers for complicated networks but is helpful for end hosts and routers serving small networks. Satisfies: SRG-OS-000420-GPOS-00186, SRG-OS-000142-GPOS-00079

Related controls

CCI-001103, CCI-002385

Fix

Configure RHEL 10 to use reverse path filtering on IPv4 interfaces by default. Create a configuration file if it does not already exist: $ sudo vi /etc/sysctl.d/ipv4_rp_filter.conf Add the following line to the file: net.ipv4.conf.default.rp_filter = 1 Reload settings from all system configuration files with the following command: $ sudo sysctl --system