Google researchers have detailed a sophisticated hacking operation that exploited vulnerabilities in Chrome and Windows to install malware on Android and Windows devices.
Some of the exploits were zero-days, meaning they targeted vulnerabilities that at the time were unknown to Google, Microsoft, and most outside researchers (both companies have since patched the security flaws). The hackers delivered the exploits through watering-hole attacks, which compromise sites frequented by the targets of interest and lace the sites with code that installs malware on visitors’ devices. The compromised sites made use of two exploit servers, one for Windows users and the other for users of Android.
The use of zero-days and complex infrastructure isn’t in itself a sign of sophistication, but it does show above-average skill by a professional team of hackers. Combined with the robustness of the attack code—which chained together multiple exploits in an efficient manner—the campaign demonstrates it was carried out by a “highly sophisticated actor.”
“These exploit chains are designed for efficiency & flexibility through their modularity,” a researcher with Google’s Project Zero exploit research team wrote. “They are well-engineered, complex code with a variety of novel exploitation methods, mature logging, sophisticated and calculated post-exploitation techniques, and high volumes of anti-analysis and targeting checks. We believe that teams of experts have designed and developed these exploit chains.”
The attackers obtained remote code execution by exploiting the Chrome zero-day and several recently patched Chrome vulnerabilities. All of the zero-days were used against Windows users. None of the attack chains targeting Android devices exploited zero-days, but the Project Zero researchers said it’s likely the attackers had Android zero-days at their disposal.