Enable automatic security updates on Debian.

50unattended-upgrades

APT::Periodic::Enable "1";                                                                                                                           
APT::Periodic::Update-Package-Lists "1";                                                                                                             
APT::Periodic::AutocleanInterval "7";                                                                                                                
APT::Periodic::Unattended-Upgrade "1";                                                                                                               
                                                                                                                                                     
// Automatically upgrade packages from these (origin, archive) pairs                                                                                 
Unattended-Upgrade::Allowed-Origins {                                                                                                                
        "${distro_id} stable";                                                                                                                       
        "${distro_id} ${distro_codename}-security";                                                                                                  
//      "${distro_id} ${distro_codename}-updates";                                                                                                   
//      "${distro_id} ${distro_codename}-proposed-updates";                                                                                          
};                                                                                                                                                   
                                                                                                                                                     
// List of packages to not update                                                                                                                    
Unattended-Upgrade::Package-Blacklist {                                                                                                              
//      "vim";                                                                                                                                       
//      "libc6";                                                                                                                                     
//      "libc6-dev";                                                                                                                                 
//      "libc6-i686";                                                                                                                                
};                                                                                                                                                   
                                                                                                                                                     
// Send email to this address for problems or packages upgrades                                                                                      
// If empty or unset then no email is sent, make sure that you                                                                                       
// have a working mail setup on your system. The package 'mailx'                                                                                     
// must be installed or anything that provides /usr/bin/mail.                                                                                        
//Unattended-Upgrade::Mail "root@localhost";                                                                                                         
                                                                                                                                                     
// Do automatic removal of new unused dependencies after the upgrade                                                                                 
// (equivalent to apt-get autoremove)                                                                                                                
//Unattended-Upgrade::Remove-Unused-Dependencies "false";                                                                                            
                                                                                                                                                     
// Automatically reboot *WITHOUT CONFIRMATION* if a                                                                                                  
// the file /var/run/reboot-required is found after the upgrade                                                                                      
//Unattended-Upgrade::Automatic-Reboot "false";                                                                                                      
                                                                                                                                                     
                                                                                                                                                     
// Use apt bandwidth limit feature, this example limits the download                                                                                 
// speed to 70kb/sec                                                                                                                                 
//Acquire::http::Dl-Limit "70";