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UBTU-16-030540 - The Ubuntu 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 Ubuntu operating system to not forward Internet Protocol version 4 (IPv4) source-routed packets by default with the following command:

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

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_CAN_Ubuntu_16-04_LTS_V2R3_STIG.zip

Item Details

Category: CONFIGURATION MANAGEMENT

References: 800-53|CM-6b., CAT|II, CCI|CCI-000366, Rule-ID|SV-215147r610931_rule, STIG-ID|UBTU-16-030540, STIG-Legacy|SV-90555, STIG-Legacy|V-75875, Vuln-ID|V-215147

Plugin: Unix

Control ID: d339233941b485610c2411e8bbc219782c9b9c02dc4f4f71907f792621d5c46b