Signing the hash of the signer's certficate

["Anders Rundgren" <anders.rundgren@xxxxxxxxx>]

It seems that neither CMS nor XML Dsig explicitly
support signing the hash of the signer's certificate.

But this has been added to ETSI's XAdES.

I understand that the reason for this addition was to thwart
changing the client certificate.

However, there must be a considerable difficulty
finding a client certificate with an identical public key
(and a provable possession of a matching private key),
which is required in order to succeed with this attack.

Any thoughts about this?

Anders R