Editar o sources.list com Geditgedit /etc/apt/sources.list
# Line commented out by installer because it failed to verify: deb http://security.debian.org/ wheezy/updates main # Line commented out by installer because it failed to verify: # deb-src http://security.debian.org/ wheezy/updates main # wheezy-updates, previously known as 'volatile' # A network mirror was not selected during install. The following entries # are provided as examples, but you should amend them as appropriate # for your mirror of choice. deb http://ftp.debian.org/debian/ wheezy-updates main # deb-src http://ftp.debian.org/debian/ wheezy-updates main #debian # deb http://http.us.debian.org/debian/ wheezy main contrib non-free # deb ftp://mirrors.kernel.org/debian/ wheezy main contrib non-free # deb http://download.unesp.br/linux/debian/ wheezy main contrib non-free deb http://ftp.br.debian.org/debian/ wheezy main contrib non-free deb-src http://ftp.br.debian.org/debian/ wheezy main contrib non-free #som video #deb http://www.deb-multimedia.org wheezy main non-free #deb http://www.deb-multimedia.org wheezy-backports main #deb http://linorg.usp.br/debian-marillat/ wheezy main non-free #deb-src http://linorg.usp.br/debian-marillat/ wheezy main non-free deb ftp://ftp.br.debian.org/debian-multimedia wheezy main non-free deb-src ftp://ftp.br.debian.org/debian-multimedia wheezy main non-free deb ftp://ftp.br.debian.org/debian-multimedia wheezy-backports main #backports #deb ftp://ftp.br.debian.org/debian wheezy-backports main contrib non-free deb http://linorg.usp.br/debian wheezy-backports main contrib non-free
e também adicione as chaves
gpg --keyserver subkeys.pgp.net --recv-keys 07DC563D1F41B907 gpg --export --armor 07DC563D1F41B907 | apt-key add -
e termine executando:
apt-get update