MP3 files pose as music from stars such as Elvis Presley, Fergie and Carrie Underwood. They contain a monotone voice encouraging people to buy shares in a little-known company. The voice on the MP3 file says the following: ‘Hello, this is an investor alert. Go read the news and [obscured] on EXTO. That symbol again is EXTO’ The voice is randomly altered in an attempt to avoid detection by anti-spam filters. Some of the files repeat the message twice, rather than once.”]
Source: https://www.darkreading.com/attacks-breaches/spammers-pump-dump-with-tunes