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V-261322

CAT II (Medium)

SLEM 5 must not forward Internet Protocol version 6 (IPv6) source-routed packets by default.

Rule ID

SV-261322r996436_rule

STIG

SUSE Linux Enterprise Micro (SLEM) 5 Security Technical Implementation Guide

Version

V1R4

CCIs

CCI-000366

Discussion

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.

Check Content

Verify SLEM 5 does not accept IPv6 source-routed packets by default with the following command:

     > sudo sysctl net.ipv6.conf.default.accept_source_route
     net.ipv6.conf.default.accept_source_route = 0

If the network parameter "ipv6.conf.default.accept_source_route" is not equal to "0", or nothing is returned, this is a finding.

Fix Text

Configure SLEM 5 to disable IPv6 default source routing by running the following command as an administrator:

     > sudo sysctl -w net.ipv6.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.ipv6.conf.default.accept_source_route=0" >> /etc/sysctl.d/99-stig.conf'

     > sudo sysctl --system