DotnetCat

Remote command shell application written in C#, targeting the .NET 8 runtime.

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Overview

DotnetCat is a multithreaded console application that can be used to spawn bind and reverse command shells, upload and download files, perform connection testing, and transmit user-defined payloads. This application uses Transmission Control Protocol (TCP) network sockets to perform network communications.

At its core, DotnetCat is built of unidirectional TCP socket pipelines, each responsible for asynchronously reading from or writing to a connected socket. This allows a single socket stream to be used by multiple pipelines simultaneously without thread lock issues occurring.

Features

• Bind command shells
• Reverse command shells
• Remote file uploads and downloads
• Connection probing
• User-defined data transmission

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Basic Usage

• Linux Systems

  dncat [OPTIONS] TARGET

• Windows Systems

  dncat.exe [OPTIONS] TARGET

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Command-Line Arguments

All available DotnetCat arguments are listed in the following table:

Argument	Type	Description	Default
TARGET	Required	Host to use for the connection	N/A
-p/--port PORT	Optional	Port to use for the connection	44444
-e/--exec EXEC	Optional	Pipe executable I/O data (shell)	N/A
-o/--output PATH	Optional	Download a file from a remote host	N/A
-s/--send PATH	Optional	Send a local file to a remote host	N/A
-t, --text	Optional	Send a string to a remote host	False
-l, --listen	Optional	Listen for an inbound connection	False
-z, --zero-io	Optional	Determine if an endpoint is open	False
-v, --verbose	Optional	Enable verbose console output	False
-d, --debug	Optional	Enable verbose error output	False
-h/-?, --help	Optional	Display the app help menu and exit	False

See the usage examples section for more information.

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Installation

Installers (Recommended)

The tools directory contains Linux and Windows installer and uninstaller scripts.

Linux Systems

The dncat-install.sh installer can be used to install DotnetCat on Linux systems.

The following code snippet can be executed in Bash to download and run the dncat-install.sh DotnetCat installer:

curl -sLS "https://raw.githubusercontent.com/vandavey/DotnetCat/master/tools/dncat-install.sh" | bash

DotnetCat can be uninstalled using the dncat-uninstall.sh uninstaller.

dncat-install.sh and dncat-uninstall.sh only support ARM64 and x64 Linux systems and require curl and unzip to be installed.

Windows Systems

The dncat-install.ps1 installer can be used to install DotnetCat on Windows systems.

The following code snippet can be executed in PowerShell to download and run the dncat-install.ps1 DotnetCat installer:

$Uri = "https://raw.githubusercontent.com/vandavey/DotnetCat/master/tools/dncat-install.ps1"
(Invoke-WebRequest $Uri -DisableKeepAlive).Content | powershell.exe -

DotnetCat can be uninstalled using the dncat-uninstall.ps1 uninstaller.

dncat-install.ps1 and dncat-uninstall.ps1 only support x64 and x86 Windows systems and must be executed as an administrator.

Manual Setup

The entire DotnetCat source code repository can be downloaded here.

To download a precompiled standalone executable, select one of the options below:

• Linux-x64
• Linux-ARM64
• Windows-x64
• Windows-x86

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Usage Examples

Basic Operations

• Display the application help menu, then exit:

  dncat --help

• Connect to remote endpoint 192.168.1.1:1524:

  dncat "192.168.1.1" --port 1524

• Listen for an inbound connection on any local Wi-Fi interface:

  dncat --listen

  When the -l or --listen flag is specified, TARGET defaults to 0.0.0.0.

• Determine if localhost is accepting connections on port 22:

  dncat -z localhost -p 22

Command Shells

• Connect to remote endpoint 127.0.0.1:4444 to establish a bind shell:

  dncat "127.0.0.1" -p 4444

• Listen for an inbound connection to establish a reverse bash shell:

  dncat -lv --exec bash

Data Transfer

• Transmit string payload Hello world! to remote endpoint fake.addr.com:80:

  dncat -dt "Hello world!" fake.addr.com -p 80

File Transfer

• Listen for inbound file data and write the contents to path C:\TestFile.txt:

  dncat -lvo C:\TestFile.txt

• Transmit the contents of file /home/user/profit.json to remote target Joe-Mama:

  dncat --send /home/user/profit.json Joe-Mama

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Remarks

• This application is designed to be used as a multi-functional command-line networking tool, and should only be used on your own systems.

• Please use discretion, as this application is still in development.

• In no event shall the authors or copyright holders of this software be liable for any claim, damages or other liability arising from, out of or in connection with the software or the use or other dealings in the software.

  For more information, click here to view the software's MIT license.

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Copyright & Licensing

The DotnetCat application source code is available here and licensed under the MIT license.