Finding ID | Version | Rule ID | IA Controls | Severity |
---|---|---|---|---|
V-221873 | OL07-00-040610 | SV-221873r880636_rule | Medium |
Description |
---|
Source-routed packets allow the source of the packet to suggest that routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the forwarding of source-routed traffic, such as when IPv4 forwarding is enabled and the system is functioning as a router. |
STIG | Date |
---|---|
Oracle Linux 7 Security Technical Implementation Guide | 2023-03-06 |
Check Text ( C-23588r880634_chk ) |
---|
Verify the system does not accept IPv4 source-routed packets. # grep -r net.ipv4.conf.all.accept_source_route /run/sysctl.d/* /etc/sysctl.d/* /usr/local/lib/sysctl.d/* /usr/lib/sysctl.d/* /lib/sysctl.d/* /etc/sysctl.conf 2> /dev/null net.ipv4.conf.all.accept_source_route = 0 If "net.ipv4.conf.all.accept_source_route" is not configured in the /etc/sysctl.conf file or in any of the other sysctl.d directories, is commented out, or does not have a value of "0", this is a finding. Check that the operating system implements the accept source route variable with the following command: # /sbin/sysctl -a | grep net.ipv4.conf.all.accept_source_route net.ipv4.conf.all.accept_source_route = 0 If the returned line does not have a value of "0", this is a finding. If conflicting results are returned, this is a finding. |
Fix Text (F-23577r880635_fix) |
---|
Set the system to the required kernel parameter by adding the following line to "/etc/sysctl.conf" or a configuration file in the /etc/sysctl.d/ directory (or modify the line to have the required value): net.ipv4.conf.all.accept_source_route = 0 Issue the following command to make the changes take effect: # sysctl -system |