The system must prevent local applications from generating source-routed packets.

From SUSE Linux Enterprise Server v11 for System z

Associated with: CCI-001551

SV-46276r1_rule The system must prevent local applications from generating source-routed packets.

Vulnerability discussion

Source-routed packets allow the source of the packet to suggest routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures.

Check content

Check the reverse source route settings for the system: # sysctl net.ipv4.conf.all.accept_source_route # sysctl net.ipv4.conf.default.accept_source_route If either setting has a value other than zero, this is a finding.

Fix text

Add the entries in /etc/sysctl.conf to disable reverse source routing: # printf "sysctl net.ipv4.conf.all.accept_source_route = 0\n" >> /etc/sysctl.conf # printf "sysctl net.ipv4.conf.default.accept_source_route = 0\n" >> /etc/sysctl.conf Activate the updated settings: # /sbin/sysctl -p /etc/sysctl.conf

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