10. Security Considerations

This extension to BGP does not change the underlying security issues inherent in the existing BGP, except for the following:

The inconsistency between the AS_PATH attribute and the AS4_PATH attribute can create loss of the AS path information, and potential routing loops in certain cases, as discussed in this document. This could be exploited by an attacker.

It is a misconfiguration to assign a non-mappable four-octet AS number as the "Member AS Number" in a BGP Confederation before all the BGP speakers within the Confederation have transitioned to support four-octet AS numbers. Such a misconfiguration would weaken AS path loop detection within a Confederation.