The real research: https://citizenlab.ca/research/how-discover-tech-turned-targeted-ads-into-a-pipeline-for-spyware/

Here is the boiled down points from this

1. you open a page that has an ad served from Discovery-Tech ad inventory

2. the ad has a standard script in to that calls back to the home server and passes your advertising ID (cookie ID on desktop or mobile ID on mobile) plus your IP

3. there is a third party that has compiled a list of ad ID + IP that effectively de-anonymizes users. This is used to target specific people. The info passed by the ad is compared against the target list. If there is no match to the target nothing further happens.

4. if a match is found it returns javascript that runs on the page. It finger prints the device then it checks for an exploit.

5. if the exploit it is looking for is found the exploit corrupts memory in the rendering engine, achieves native code execution, escapes the sandbox, and installs the spyware.

And, yes, ad blocker software would stop this. If the ad cannot render it cannot call back to the mothership. The only exception to this would be if the ad was served first party, like the website you were visiting was also hosting the ad. Or if you are on a device using a browser that is part of a app that does not have ad blocking, like the built in browser for instagram.

Here is what they did not say

We don't know which browser, OS, or application vulnerability was used at Al Jazeera. It could be a unknown zero day one or a one that is known but only works on certain older versions of software.

Adding in a standard YSK how to delete your advertising ID from your mobile device.