The Messenger of Allah ﷺ performed the qunut for a full month during the Zuhr, Asr, Maghrib, Isha, and Fajr prayers. At the end of every prayer, after saying "Sami Allahu liman hamidah" in the final rakah, he would supplicate against certain clans of Banu Sulaym, namely Ril, Zakwan, and Usayyah, while those praying behind him said "Amin."
حدثنا عبد الله بن معاوية الجمحي حدثنا ثابت بن يزيد عن هلال بن خباب عن عكرمة
قنت رسول الله ﷺ شهرا متتابعا في الظهر والعصر والمغرب والعشاء وصلاة الصبح في دبر كل صلاة إذا قال سمع الله لمن حمده من الركعة الآخرة يدعو على أحياء من بني سليم على رعل وذكوان وعصية ويؤمن من خلفه
Grading, [hasan]. Ahmad narrated it, 1/301, from the hadith of Thabit bin Yazid, with the same wording, and Ibn Khuzayma graded it sahih, no. 618, and Hakim graded it as meeting the standard of Bukhari, 1/225, and Dhahabi agreed with him (!). The hadith has corroborating narrations in Daraqutni, 2/37, no. 1671, and elsewhere.