Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) said that for one month the Messenger of Allah (peace and blessings be upon him) kept reciting the qunut in the last rak'ah of the Zuhr, Asr, Maghrib, Isha and Fajr prayers after saying 'Sami'a Allahu liman hamidah' (Allah has heard the one who praised Him). In it he would supplicate against Ri'l, Dhakwan and Usayyah of Banu Sulaym from among the Arab tribes, and those praying behind him would say "Amin".
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 3153