C:>SET CSV="Feb 2, 2018 10:50:49.996148000 ";"172.16.21.120";"54859";"196.58.210.193";"9889";"19:68:09:24:00:5b:00:7e:53:53:4c:2e:47:6f:6f:67:6c:65:00:00:00:00:00:00"

C:>echo %CSV% |  perl -F; -ane "$F[5]=qq|\"BitTorrent\"|;print join q|;|,@F"
"Feb 2, 2018 10:50:49.996148000 ";"172.16.21.120";"54859";"196.58.210.193";"9889";"BitTorrent"