N.Y. Real Property Actions & Proceedings Law § 232

§ 232. Purchases by certain officers prohibited; penalty. No officer\nmaking a sale as prescribed in section 231, or guardian of an infant\nparty, or any person for his benefit, directly or indirectly, shall\npurchase or be interested in the purchase of any of the property sold;\nexcept that a guardian, where he is lawfully authorized to do so, may\npurchase for the benefit or in behalf of his ward. The violation of this\nsection is a misdemeanor; and a purchase made contrary to this section\nis void.\n