Spyware vendors use exploit chains to take advantage of patch delays in mobile ecosystem

Several commercial spyware vendors developed and used zero-day exploits against iOS and Android users last year. However, their exploit chains also relied on known vulnerabilities to work, highlighting the importance of both users and device manufacturers to speed up the adoption of security patches.

“The zero-day exploits were used alongside n-day exploits and took advantage of the large time gap between the fix release and when it was fully deployed on end-user devices,” researchers with Google’s Threat Analysis Group (TAG) said in a report detailing the attack campaigns. “Our findings underscore the extent to which commercial surveillance vendors have proliferated capabilities historically only used by governments with the technical expertise to develop and operationalize exploits.”

The iOS spyware exploit chain

Apple has a much tighter grip on its mobile ecosystem being both the sole hardware manufacturer of iOS devices and the creator of the software running on them. As such, iPhones and iPads have historically had a much better patch adoption rate than Android, where Google creates the base OS and then tens of device manufacturers customize it for their own products and maintain their own separate firmware.

In November 2022, Google TAG detected an attack campaign via SMS that targeted both iOS and Android users in Italy, Malaysia, and Kazakhstan using exploit chains for both platforms. The campaign involved bit.ly shortened URLs that, when clicked, directed users to a web page delivering the exploits then redirected them to legitimate websites, such as the shipment tracking portal for Italian logistics company BRT or a popular news site from Malaysia.

The iOS exploit chain combined a remote code execution vulnerability in WebKit, Apple’s website rendering engine used in Safari and iOS, that was unknown and unpatched at the time. The flaw, now tracked as CVE-2022-42856, was patched in January after Google TAG reported it to Apple.

However, a remote code execution flaw in the web browser engine is not enough to compromise a device, because mobile operating systems like iOS and Android use sandboxing techniques to limit the privileges of the browser….