Could You share some online publications about out-of-band data ?
Yes, more posts about it and how security is managed are coming... 😅
how does the HAS protocol prevent such an attack ?
That will be addressed in the coming posts too.
TLDR; auth_req
sent by a malicious app to HAS will expire and be ignored if the user's PKSA is not running. If the PKSA is running, PKSA should ignore them if they did not retrieve a matching off-band auth_req_payload
before.