The Adventures of the Jamison Family: Security Surprises On Firefox Quantum

This morning I've found an scaring surprise on my Firefox Quantum. Casually it was connected to a proxy when an unexpected connection came up, the browser was connecting to an unknown remote site via HTTP and downloading a ZIP that contains an ELF shared library, without any type of signature on it.

This means two things

1) the owner of that site might spread malware infecting many many people.
2) the ISP also might do that.

Ubuntu Version:

Firefox Quantum version:

The URL: hxxp://ciscobinary.openh264.org/openh264-linux64-0410d336bb748149a4f560eb6108090f078254b1.zip

The zip contains these two files:
3f201a8984d6d765bc81966842294611 libgmpopenh264.so
44aef3cd6b755fa5f6968725b67fd3b8 gmpopenh264.info

The info file:
Name: gmpopenh264
Description: GMP Plugin for OpenH264.
Version: 1.6.0
APIs: encode-video[h264], decode-video[h264]

So there is a remote codec loading system that is unsigned and unencrypted, I think is good to be aware of it.

In this case the shared library is a video decoder, but it would be a vector to distribute malware o spyware massively, or an attack vector for a MITM attacker.