It's odd to refer to this income as unearned in regards to the DWP, as the DWP would very much consider letting property an activity akin to working when claiming UC or PIP.
The answer to your question is that it varies according to context and circumstances. You would need to give me a precise and concrete example involving the Benefits involved. There is also case law and HMRC law to consider.
David
Nothing on this board constitutes legal advice - always consult a professional about specific problems