2015 New York Laws
AGM - Agriculture & Markets
Article 7 - (Agriculture & Markets) LICENSING, IDENTIFICATION AND CONTROL OF DOGS
123-A - Exemption from civil liability.

  123-a. Exemption from civil liability. 1. If any dog shall, without
  justification,  attack  a  person,  or  behaves  in  a  manner  which  a
  reasonable person would believe poses a serious and unjustified imminent
  threat  of  serious  physical  injury  to  a person, when such person is
  peaceably conducting himself in a place where he may lawfully  be,  such
  person  or  any  other person witnessing the attack or threatened attack
  may destroy such dog while so attacking, and no liability in damages  or
  otherwise shall be incurred on account of such destruction.
2. If any dog shall, without justification, attack a companion animal,
  farm  animal  or  domestic  animal,  or shall behave in a manner which a
  reasonable person would believe poses a serious and unjustified imminent
  threat of serious physical injury or death to a companion  animal,  farm
  animal  or  domestic  animal, where such animal is in any place where it
  may lawfully be, the owner or caretaker of such  animal,  or  any  other
  person  witnessing the attack, may destroy such dog, and no liability in
  damages or otherwise shall be incurred on account of such destruction.