I was getting the 404 with several tools when apt-get update && apt-get upgrade. This command worked.
wget -q -O – archive.kali.org/archive-key.asc | apt-key add
You can read more up on repositories on below but the sources.list file should look like this
deb http://http.kali.org/kali kali-rolling main contrib non-free
# For source package access, uncomment the following line
deb-src http://http.kali.org/kali kali-rolling main contrib non-free
I assume this is the case if you just downloaded and install, but may not be the case for older versions of kali. EXAMPLE… Last semester!
You may also have the “#” in front of yours. Notice the “#” is gone before the one above. You will need to remove the “#” if you want to use source packages when “playing” certain tools included with kali.