The router must have IP source routing disabled.

From Perimeter L3 Switch Security Technical Implementation Guide - Cisco

Part of IP Source Routing is not disabled on all routers.

SV-15316r2_rule The router must have IP source routing disabled.

Vulnerability discussion

Source routing is a feature of IP, whereby individual packets can specify routes. This feature is used in several different network attacks by bypassing perimeter and internal defense mechanisms.

Check content

Review the configuration to determine if source routing is enabled. The IOS command no ip source-route must be included in the configuration.

Fix text

Configure the router to disable IP source routing.

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