Detections
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SLEM-05-253015 - SLEM 5 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 SLEM 5 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_SLEM_5_V1R4_STIG.zip
Item Details
Category: CONFIGURATION MANAGEMENT
References: 800-53|CM-6b., CAT|II, CCI|CCI-000366, Rule-ID|SV-261314r996412_rule, STIG-ID|SLEM-05-253015, Vuln-ID|V-261314
Plugin: Unix
Control ID: faf5fddf4c555f2535c4a556e69beef35675e855ef59f9b808e8ef0f177d481f