Attackers are exploiting a zero-day vulnerability in Google’s Android mobile operating system that can give them full control of at least 18 different phone models, including four different Pixel models, a member of Google’s Project Zero research group said on Thursday night.
There’s evidence the vulnerability is being actively exploited, either by exploit developer NSO Group or one of its customers, Project Zero member Maddie Stone said in a post. NSO representatives, meanwhile, said the “exploit has nothing to do with NSO.” Exploits require little or no customization to fully root vulnerable phones. The vulnerability can be exploited two ways: (1) when a target installs an untrusted app or (2) for online attacks, by combining the exploit with a second exploit targeting a vulnerability in code the Chrome browser uses to render content.
“The bug is a local privilege escalation vulnerability that allows for a full compromise of a vulnerable device,” Stone wrote. “If the exploit is delivered via the Web, it only needs to be paired with a renderer exploit, as this vulnerability is accessible through the sandbox.”
The use-after-free vulnerability originally appeared in the Linux kernel and was patched in early 2018 in version 4.14, without the benefit of a tracking CVE. That fix was incorporated into versions 3.18, 4.4, and 4.9 of the Android kernel. For reasons that weren’t explained in the post, the patches never made their way into Android security updates. That would explain why earlier Pixel models are vulnerable and later ones are not. The flaw is now tracked as CVE-2019-2215.
Project Zero gives developers 90 days to issue a fix before publishing vulnerability reports except in cases of active exploits. The Android vulnerability in this case was published seven days after it was privately reported to the Android team.
The exploit has been seen being used in the wild, which is why it was disclosed after 7 days.