https://top-hat-sec.com/forum/index.php?topic=2715.0
Abrir /etc/apt/sources.list e adicionar entrada
kali
deb http://ppa.launchpad.net/wagungs/kali-linux2/ubuntu YOUR_UBUNTU_VERSION_HERE main
deb-src http://ppa.launchpad.net/wagungs/kali-linux2/ubuntu YOUR_UBUNTU_VERSION_HERE main
deb http://ppa.launchpad.net/wagungs/kali-linux/ubuntu YOUR_UBUNTU_VERSION_HERE main
deb-src http://ppa.launchpad.net/wagungs/kali-linux/ubuntu YOUR_UBUNTU_VERSION_HERE main
exemplo
deb http://ppa.launchpad.net/wagungs/kali-linux2/ubuntu raring main
agora copiam a chave do repo para um arquivo texto -
- Código: Selecionar todos
-----BEGIN PGP PUBLIC KEY BLOCK-----
Version: SKS 1.1.4
Comment: Hostname: keyserver.ubuntu.com
mI0ET324YwEEANbSlISrOlAGjxgFRxiN6jk0JIl/vxQ8lapRdxZ4DHDAQdXbX4AuigMBkP5e
sOxhMpDnkgMRtEVpaBMdQheA0/431pPQYqkr3jdeZw5JS5opiyJ4qr/QrcoSFHSluEkWkbZ6
RYOkA25vW31KK2FB2LQVRYk580llXAVgIUznm2ATABEBAAG0GExhdW5jaHBhZCBQUEEgZm9y
IHdhZ3VuZ4i4BBMBAgAiBQJPfbhjAhsDBgsJCAcDAgYVCAIJCgsEFgIDAQIeAQIXgAAKCRAb
IuuNj9/bVxabBADSGN8cp+hqkdZqwq263wdz/UGsiuB1bCrH06/HznC/ZC5rjfH3aQ1Dwwag
zYCrSD3c0cKNAqD10009N76RMlzZBH8kKL9khH3zPL/k4/lYuVP7y6NKFbBsnawEUc0mWcCa
mH4ScTdWWPXP/mOQiUUjnQ1bZhzpcbQOb+hEUAqExg==
=fJ+8
-----END PGP PUBLIC KEY BLOCK-----
Abrir synaptic e procurar aba
Configurações - Repositórios.
Dentro desta janela procurar - Autenticação.
Feito isso importam a chave e fazem um update, recarregar no synaptic.
Pronto.