Reference: http://www.alifta.net/Fatawa/FatawaDetails.aspx?languagename=ar&View=Page&PageID=10077&PageNo=1&BookID=3
Question: What is the ruling regarding listening to backbiting?
Response: Listening to backbiting is prohibited, because [in doing so you are showing your] approval of this detested act. [In addition to that], backbiting is from the major sins, so it is obligatory to rebuke the one doing so.
And with Allaah lies all the success, and may Allaah send prayers and salutations upon our Prophet Muhammad ﷺ and his family and his companions.