*** This bug is a security vulnerability ***

Public security bug reported:

There is install-css.sh in libdvdread4 package which downloads and
installs libdvdcss package which is needed for playing of DVDs (those
infected by DRM CSS technology – probably most of them).

The libdvdcss package is downloaded over unencrypted HTTP protocol and
is installed immediately after downloading without any integrity checks.
Anybody between the server (download.videolan.org) and the user can
modify on-thy-fly this package and add some malware/backdoor into it.
This installation equals downloading some untrusted code from the Net
and executing it with root permissions (the package can containt post-
installation script).

User is not warned (neither in help
https://help.ubuntu.com/community/RestrictedFormats/PlayingDVDs nor
interactively by the script) that his computer might be infected.

The script MUST verify the digital signature of downloaded package and
install it only if it is valid.

The package is already signed:
http://download.videolan.org/pub/debian/stable/stable/libdvdcss_1.2.13-0.dsc
So please verify that the PGP key C0AFF10F (Rafaël Carré) is valid and can be 
trusted for this purpose. And add signature verification into the 
install-css.sh script.

Please consult with lawyers also other solution: isn't is possible to
distribute DeCSS source code instead of downloading it from an external
site? So the subject of distribution will be just data, nothing
executable. The compilation will be done by the user on his computer (he
will run the same script: install-css.sh). It will not be vulnerable to
MITM attack – standard methods for package signing and verification will
be used – and it will also be independent from Internet connectivity –
it will by possible to install it e.g. from CDs on an offline computer.

** Affects: libdvdread (Ubuntu)
     Importance: Undecided
         Status: New

** Information type changed from Private Security to Public Security

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https://bugs.launchpad.net/bugs/1317386

Title:
  Script install-css.sh from libdvdread4 is vulnerable to MITM attack

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