> The report is highly sensationalist in the "zero-click" aspect. It details to some degree the aspects of distribution and C&C but goes very vague the main point - what was the mechanism that activated that zero malware in a zero-click fashion.
It read to me like it was assumed to be using OS/browser/application-level exploits to get further access to target devices. I suspect the CitizenLab report is light on details in particular because they don't actually know them:
> In most cases, the user who sees the ad is not selected for targeting, and the server will not return any JavaScript to be executed.
> A large number of ads placed by Discover-Tech contain a script tag pointing back to what the company refers to as a “NOAS server” (also called a “getAd server”). This tag causes the ad, when rendered, to connect back to Discover-Tech, submit advertising identifiers for the user (either a cookie ID or a mobile ad ID), and automatically execute any JavaScript code returned. The NOAS server decides, apparently based on a combination of the source IP address and the advertising identifiers, whether the target is eligible to receive any JavaScript. If so, then code is returned. If not, a 0-byte response is returned. The NOAS server is a key part of Discover-Tech’s strategy, allowing Discover-Tech to avoid directly sharing malicious code, or even pointers to malicious code, with the companies who serve and display the ads.
It read to me like it was assumed to be using OS/browser/application-level exploits to get further access to target devices. I suspect the CitizenLab report is light on details in particular because they don't actually know them:
> In most cases, the user who sees the ad is not selected for targeting, and the server will not return any JavaScript to be executed.
> A large number of ads placed by Discover-Tech contain a script tag pointing back to what the company refers to as a “NOAS server” (also called a “getAd server”). This tag causes the ad, when rendered, to connect back to Discover-Tech, submit advertising identifiers for the user (either a cookie ID or a mobile ad ID), and automatically execute any JavaScript code returned. The NOAS server decides, apparently based on a combination of the source IP address and the advertising identifiers, whether the target is eligible to receive any JavaScript. If so, then code is returned. If not, a 0-byte response is returned. The NOAS server is a key part of Discover-Tech’s strategy, allowing Discover-Tech to avoid directly sharing malicious code, or even pointers to malicious code, with the companies who serve and display the ads.