The Skype debian packege for Skype (even when not installed via their
offical repo) automatically installs apt configuration that adds
Microsoft's apt repo to the system's package sources.
That way, Microsoft (or anybody holding their repo's private key)
can easily inject malicious packages via regular update and replace
distro packages w/ their own manipulated ones.
Suggested vendor solution:
Remove all apt configuration stuff from the .deb.
a) remove Skype's apt config (sources.list entry as well as the
Microsoft apt key) immediately after installation
b) unpack and repackage it manually (w/o that apt config) before
installation on production machines
c) use apt pinning to restrict the Microsoft repo to only the
c) only install it in a strictly confined container
Enrico Weigelt, metux IT consult
Free software and Linux embedded engineering
email@example.com -- +49-151-27565287