It was narrated from Sa'eed bin Zaid bin 'Amr bin Nufail that the Prophet (ﷺ) said:
"Whoever is killed defending his property, he is a martyr." (ID)
English reference (ID): Vol. 3, Book 20, Hadith 2580 (ID)
Arabic reference (ID): Book 20, Hadith 2678 (ID)