كتاب الْمَسَاجِدِ وَمَوَاضِعِ الصَّلاَةِ
5  
The Book of Mosques and Places of Prayer
(54)
Chapter: It is recommended to say qunut in all prayers if a calamity befalls the Muslims – and refuge is sought from Allah (regarding that). It is recommended to say qunut in Subh at all times. And the clarification that it is to be said after raising the head from bowing in the final rak`ah, and it is recommended to say it out loud
(54)
باب اسْتِحْبَابِ الْقُنُوتِ فِي جَمِيعِ الصَّلاَةِ إِذَا نزَلَتْ بِالْمُسْلِمِينَ نَازِلَةٌ ‏‏
Sahih Muslim 677 g

This hadith has been narrated by Anas with another chain of transmitters and with minor additions.

وَحَدَّثَنَا أَبُو كُرَيْبٍ، حَدَّثَنَا حَفْصٌ، وَابْنُ، فُضَيْلٍ ح وَحَدَّثَنَا ابْنُ أَبِي عُمَرَ، حَدَّثَنَا مَرْوَانُ، كُلُّهُمْ عَنْ عَاصِمٍ، عَنْ أَنَسٍ، عَنِ النَّبِيِّ صلى الله عليه وسلم بِهَذَا الْحَدِيثِ ‏.‏ يَزِيدُ بَعْضُهُمْ عَلَى بَعْضٍ ‏.‏
Reference : Sahih Muslim 677g
In-book reference : Book 5, Hadith 384
USC-MSA web (English) reference : Book 4, Hadith 1439
  (deprecated numbering scheme)