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Researcher Publishes PoC Exploit for Recent Android Zero-Day

A security researcher has published a proof-of-concept (PoC) exploit for the recently addressed Android zero-day vulnerability that impacts Pixel 2 devices.

Tracked as CVE-2019-2215, the existence of this vulnerability was made public at the beginning of October, when Google Project Zero security researcher Maddie Stone revealed that attackers had already been targeting vulnerable devices.

At the time, the researcher also said that the information she had was pointing to an exploit used by Israeli spyware company NSO, which is known for building the infamous iOS malware Pegasus.

The vulnerability had been previously addressed in December 2017 in version 4.14 of the Linux kernel, but a CVE was not assigned at the time. The Android Open Source Project (AOSP) 3.18 kernel, AOSP 4.4 kernel, and AOSP 4.9 kernel also included the patch.

However, fully patched Pixel 1 and Pixel 2 devices, as well as Huawei P20; Xiaomi Redmi 5A, Redmi Note 5, and A1; Oppo A3; Motorola Moto Z3; LG phones running Android 8 Oreo; and Samsung Galaxy S7, S8 and S9 were found to be vulnerable.

Last week, Google released its October 2019 set of security patches for Android, and said at the time that Pixel 1 and Pixel 2 phones will receive a fix for CVE-2019-2215 as part of the October update.

This week, Grant Hernandez, a PhD candidate at the Florida Institute of Cyber Security at the University of Florida, published a blog post containing a working proof-of-concept exploit targeting the vulnerability.

“The base PoC left us with a full kernel read/write primitive, essentially game over for the systems’ security, but left achieving root as an exercise for the reader,” the researcher notes.

To get a full root shell, one would need to bypass the multiple layers of enforcement the Android platform features, including Discretionary Access Control (DAC), Mandatory Access Control (MAC), Linux Capabilities (CAP), and Secure Computing Mode (SECCOMP).

“On a modern Android system, this is a significant undertaking without a kernel vulnerability. But with an app accessible kernel exploit, we have the ability to bypass or disable all of these with relative ease,” Hernandez says.

The researcher also published details on how DAC and CAP can be bypassed and how SELinux and SECCOMP can be disabled, essentially providing all of the necessary information on how an attacker could abuse the exploit to achieve root on a vulnerable device.

The necessary code is available on GitHub. Once compiled, it provides users with an application targeting CVE-2019-2215.

Related: Google Patches Remote Code Execution Bugs in Android 10

Related: Zero-Day Used in the Wild Impacts Pixel 2, Other Android Phones

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