CVE-2016-2856
HIGHUbuntu Linux - Local Privilege Escalation via pt_chown Namespace Check Bypass
Title source: llmExploitation Summary
EIP tracks 1 public exploit for CVE-2016-2856. PoCs published by halfdog.
AI-analyzed exploit summary This exploit leverages a flaw in the `pt_chown` SUID binary on Ubuntu Wily and earlier, allowing an attacker to gain ownership of arbitrary `/dev/pts` devices by creating overlapping pts numbers in a user namespace. The attack involves mounting a new `devpts` instance and manipulating file descriptors to hijack ownership of a target pts device.
Description
pt_chown in the glibc package before 2.19-18+deb8u4 on Debian jessie; the elibc package before 2.15-0ubuntu10.14 on Ubuntu 12.04 LTS and before 2.19-0ubuntu6.8 on Ubuntu 14.04 LTS; and the glibc package before 2.21-0ubuntu4.2 on Ubuntu 15.10 and before 2.23-0ubuntu1 on Ubuntu 16.04 LTS and 16.10 lacks a namespace check associated with file-descriptor passing, which allows local users to capture keystrokes and spoof data, and possibly gain privileges, via pts read and write operations, related to debian/sysdeps/linux.mk. NOTE: this is not considered a vulnerability in the upstream GNU C Library because the upstream documentation has a clear security recommendation against the --enable-pt_chown option.
Exploits (1)
This exploit leverages a flaw in the `pt_chown` SUID binary on Ubuntu Wily and earlier, allowing an attacker to gain ownership of arbitrary `/dev/pts` devices by creating overlapping pts numbers in a user namespace. The attack involves mounting a new `devpts` instance and manipulating file descriptors to hijack ownership of a target pts device.
References (9)
Scores
CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H