Alcaron's Scroll & Colateral Damage

Peril in Pelargir scenario.
Enemy got Collateral Damage as shadow card ("Any damage dealt by this attack is dealt to the hero with Alcaron's Scroll attached, if able."), Alcaron's Scroll has "When the hero with Alcaron's Scroll attached is damaged by an enemy attack, attach Alcaron's Scroll to that enemy.".

Does this count as damaged by attack? My first thought was no, it is damage by card effect, but on the other hand, wording could suggest that this is not by card effect damage, it is attack damage redirected to another target.