Linux Kernel Bug Allows Local-To-Root Privilege Escalation

Tens of millions of Linux PCs and servers and 66% of all Android devices are impacted by a  vulnerability in the Linux kernel that allows privilege escalation from local to root via a use-after-free attack, according to the research team at Perception Point.

Although no exploits for the bug have been seen in the wild yet, the vulnerability is far-reaching. According to Yevgeny Pats, co-founder and CEO of Perception Point, the bug affects all Linux kernels from release 3.8 and later, both 32-bit and 64-bit, operating on desktop, server, mobile, and embedded devices. 

The vulnerability, CVE-2016-0728, is a reference leak in the keyrings facility, where security data like encryption keys and authentication keys are stored.

Keyring objects can be shared between processes by referring to the same keyring name. The reference leak occurs when an error message is generated if a process tries to replace its current session keyring with the same one. 

Once the object is leaked, it can be leveraged in a use-after-free exploit that grants the attacker root access.

For more information, see the technical analysis at: http://perception-point.io/2016/01/14/analysis-and-exploitation-of-a-linux-kernel-vulnerability-cve-2016-0728/