SLES-15-040320 - The SUSE operating system must not forward Internet Protocol version 4 (IPv4) source-routed packets by default.

Information

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.

Solution

Configure the SUSE operating system to disable IPv4 default source routing by running the following command as an administrator:

> sudo sysctl -w net.ipv4.conf.default.accept_source_route=0

If '0' is not the system's default value, add or update the following line in '/etc/sysctl.d/99-stig.conf':

> sudo sh -c 'echo 'net.ipv4.conf.default.accept_source_route=0' >> /etc/sysctl.d/99-stig.conf'

> sudo sysctl --system

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_SLES_15_V2R2_STIG.zip

Item Details

Category: CONFIGURATION MANAGEMENT

References: 800-53|CM-6b., CAT|II, CCI|CCI-000366, Rule-ID|SV-235016r991589_rule, STIG-ID|SLES-15-040320, Vuln-ID|V-235016

Plugin: Unix

Control ID: b5c3988853644c92f4b9e889b659a3dcb0cfe9c0f951b744803d0900fada9d5d