Powershell .NET Compiler - Metasploit
This page contains detailed information about how to use the post/windows/manage/powershell/build_net_code metasploit module. For list of all metasploit modules, visit the Metasploit Module Library.
Module Overview
Name: Powershell .NET Compiler
Module: post/windows/manage/powershell/build_net_code
Source code: modules/post/windows/manage/powershell/build_net_code.rb
Disclosure date: 2012-08-14
Last modification time: 2021-10-06 13:43:31 +0000
Supported architecture(s): -
Supported platform(s): Windows
Target service / protocol: -
Target network port(s): -
List of CVEs: -
This module will build a .NET source file using powershell. The compiler builds the executable or library in memory and produces a binary. After compilation the PowerShell session can also sign the executable if provided a path the a .pfx formatted certificate. Compiler options and a list of assemblies required can be configured in the datastore.
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
There are two ways to execute this post module.
From the Meterpreter prompt
The first is by using the "run" command at the Meterpreter prompt. It allows you to run the post module against that specific session:
meterpreter > run post/windows/manage/powershell/build_net_code
From the msf prompt
The second is by using the "use" command at the msf prompt. You will have to figure out which session ID to set manually. To list all session IDs, you can use the "sessions" command.
msf > use post/windows/manage/powershell/build_net_code
msf post(build_net_code) > show options
... show and set options ...
msf post(build_net_code) > set SESSION session-id
msf post(build_net_code) > exploit
If you wish to run the post against all sessions from framework, here is how:
1 - Create the following resource script:
framework.sessions.each_pair do |sid, session|
run_single("use post/windows/manage/powershell/build_net_code")
run_single("set SESSION #{sid}")
run_single("run")
end
2 - At the msf prompt, execute the above resource script:
msf > resource path-to-resource-script
Required Options
SESSION: The session to run this module on.
SOURCE_FILE: Path to source code
Knowledge Base
Example Session
/tmp/hello.cs contains the following:
using System;
public class Hello
{
public static void Main()
{
Console.WriteLine("Hello, World!");
}
}
To build and run the code:
msf exploit(handler) > use post/windows/manage/powershell/build_net_code
msf post(build_net_code) > set SESSION -1
SESSION => -1
msf post(build_net_code) > show options
Module options (post/windows/manage/powershell/build_net_code):
Name Current Setting Required Description
---- --------------- -------- -----------
ASSEMBLIES mscorlib.dll, System.dll, System.Xml.dll, System.Data.dll no Any assemblies outside the defaults
CODE_PROVIDER Microsoft.CSharp.CSharpCodeProvider yes Code provider to use
COMPILER_OPTS /optimize no Options to pass to compiler
OUTPUT_TARGET no Name and path of the generated binary, default random, omit extension
RUN_BINARY false no Execute the generated binary
SESSION -1 yes The session to run this module on.
SOURCE_FILE yes Path to source code
msf post(build_net_code) > set SOURCE_FILE /tmp/hello.cs
SOURCE_FILE => /tmp/hello.cs
msf post(build_net_code) > run
[*] Building remote code.
[+] File C:\cygwin64\tmp\aNwCFmmLzlYvPWw.exe found, 3584kb
[+] Finished!
[*] Post module execution completed
msf post(build_net_code) > sessions -i -1
[*] Starting interaction with 1...
meterpreter > shell
Process 4840 created.
Channel 7 created.
Microsoft Windows [Version 10.0.14393]
(c) 2016 Microsoft Corporation. All rights reserved.
E:\metasploit-framework>C:\cygwin64\tmp\aNwCFmmLzlYvPWw.exe
C:\cygwin64\tmp\aNwCFmmLzlYvPWw.exe
Hello, World!
You can also run the code automatically:
msf exploit(handler) > use post/windows/manage/powershell/build_net_code
msf post(build_net_code) > set SOURCE_FILE /tmp/hello.cs
SOURCE_FILE => /tmp/hello.cs
msf post(build_net_code) > set RUN_BINARY true
RUN_BINARY => true
msf post(build_net_code) > set SESSION -1
SESSION => -1
msf post(build_net_code) > run
[*] Building remote code.
[+] File C:\cygwin64\tmp\QuEQSEifJOe.exe found, 3584kb
[+] Hello, World!
[+] Finished!
[*] Post module execution completed
Go back to menu.
Msfconsole Usage
Here is how the windows/manage/powershell/build_net_code post exploitation module looks in the msfconsole:
msf6 > use post/windows/manage/powershell/build_net_code
msf6 post(windows/manage/powershell/build_net_code) > show info
Name: Powershell .NET Compiler
Module: post/windows/manage/powershell/build_net_code
Platform: Windows
Arch:
Rank: Excellent
Disclosed: 2012-08-14
Provided by:
RageLtMan <rageltman@sempervictus>
Compatible session types:
Meterpreter
Basic options:
Name Current Setting Required Description
---- --------------- -------- -----------
ASSEMBLIES mscorlib.dll, System.dll, System.Xml.dll, System.Data.dll no Any assemblies outside the defaults
CODE_PROVIDER Microsoft.CSharp.CSharpCodeProvider yes Code provider to use
COMPILER_OPTS /optimize no Options to pass to compiler
OUTPUT_TARGET no Name and path of the generated binary, default random, omit extension
RUN_BINARY false no Execute the generated binary
SESSION yes The session to run this module on.
SOURCE_FILE yes Path to source code
Description:
This module will build a .NET source file using powershell. The
compiler builds the executable or library in memory and produces a
binary. After compilation the PowerShell session can also sign the
executable if provided a path the a .pfx formatted certificate.
Compiler options and a list of assemblies required can be configured
in the datastore.
Module Options
This is a complete list of options available in the windows/manage/powershell/build_net_code post exploitation module:
msf6 post(windows/manage/powershell/build_net_code) > show options
Module options (post/windows/manage/powershell/build_net_code):
Name Current Setting Required Description
---- --------------- -------- -----------
ASSEMBLIES mscorlib.dll, System.dll, System.Xml.dll, System.Data.dll no Any assemblies outside the defaults
CODE_PROVIDER Microsoft.CSharp.CSharpCodeProvider yes Code provider to use
COMPILER_OPTS /optimize no Options to pass to compiler
OUTPUT_TARGET no Name and path of the generated binary, default random, omit extension
RUN_BINARY false no Execute the generated binary
SESSION yes The session to run this module on.
SOURCE_FILE yes Path to source code
Advanced Options
Here is a complete list of advanced options supported by the windows/manage/powershell/build_net_code post exploitation module:
msf6 post(windows/manage/powershell/build_net_code) > show advanced
Module advanced options (post/windows/manage/powershell/build_net_code):
Name Current Setting Required Description
---- --------------- -------- -----------
CERT_PATH no Path on compiler host to .pfx fomatted certificate for signing
NET_CLR_VER 4.0 no Minimum NET CLR version required to compile
Powershell::Post::dry_run false yes Return encoded output to caller
Powershell::Post::force_wow64 false yes Force WOW64 execution
Powershell::Post::log_output false yes Write output to log file
Powershell::Post::timeout 15 yes Powershell execution timeout, set < 0 to run async without termination
Powershell::encode_final_payload false yes Encode final payload for -EncodedCommand
Powershell::encode_inner_payload false yes Encode inner payload for -EncodedCommand
Powershell::exec_in_place false yes Produce PSH without executable wrapper
Powershell::exec_rc4 false yes Encrypt PSH with RC4
Powershell::method reflection yes Payload delivery method (Accepted: net, reflection, old, msil)
Powershell::no_equals false yes Pad base64 until no "=" remains
Powershell::noninteractive true yes Execute powershell without interaction
Powershell::persist false yes Run the payload in a loop
Powershell::prepend_protections_bypass true yes Prepend AMSI/SBL bypass
Powershell::prepend_sleep no Prepend seconds of sleep
Powershell::remove_comspec false yes Produce script calling powershell directly
Powershell::strip_comments true yes Strip comments
Powershell::strip_whitespace false yes Strip whitespace
Powershell::sub_funcs false yes Substitute function names
Powershell::sub_vars true yes Substitute variable names
Powershell::wrap_double_quotes true yes Wraps the -Command argument in single quotes
VERBOSE false no Enable detailed status messages
WORKSPACE no Specify the workspace for this module
Post Actions
This is a list of all post exploitation actions which the windows/manage/powershell/build_net_code module can do:
msf6 post(windows/manage/powershell/build_net_code) > show actions
Post actions:
Name Description
---- -----------
Evasion Options
Here is the full list of possible evasion options supported by the windows/manage/powershell/build_net_code post exploitation module in order to evade defenses (e.g. Antivirus, EDR, Firewall, NIDS etc.):
msf6 post(windows/manage/powershell/build_net_code) > show evasion
Module evasion options:
Name Current Setting Required Description
---- --------------- -------- -----------
Go back to menu.
Error Messages
This module may fail with the following 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.
Incompatible Environment
Here is a relevant code snippet related to the "Incompatible Environment" error message:
47: end
48:
49: def run
50: # Make sure we meet the requirements before running the script
51: unless session.type == "meterpreter" || have_powershell?
52: print_error "Incompatible Environment"
53: return 0
54: end
55:
56: # Havent figured this one out yet, but we need a PID owned by a user, can't steal tokens either
57: if client.sys.config.is_system?
Cannot run as system
Here is a relevant code snippet related to the "Cannot run as system" error message:
53: return 0
54: end
55:
56: # Havent figured this one out yet, but we need a PID owned by a user, can't steal tokens either
57: if client.sys.config.is_system?
58: print_error "Cannot run as system"
59: return 0
60: end
61:
62: # End of file marker
63: eof = Rex::Text.rand_text_alpha(8)
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Related Pull Requests
- #14202 Merged Pull Request: Implement the zeitwerk autoloader within lib/msf/core
- #14213 Merged Pull Request: Add disclosure date rubocop linting rule - enforce iso8601 disclosure dates
- #12354 Merged Pull Request: Remove targets from aux and post modules
- #11918 Merged Pull Request: replace trivial usage of expand_path with getenv
- #9010 Merged Pull Request: remove checks for hardcoded SYSTEM Account name
- #8338 Merged Pull Request: Fix msf/core and self.class msftidy warnings
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See Also
Check also the following modules related to this module:
Authors
RageLtMan <rageltman[at]sempervictus>
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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