shaas

(reverse) shell as a service

shaas is a little utility that lets you get reverse shell on demand on a remote machine. The project is made up of three executables:

• a master server (master.c)
• a client (client.c)
• a payload (payload/payload.c)

The payload is a small executable (should be <1KB on x86_64) that connects to the master server.
A client can make a request to the master server, with the port on which the client is listening as request data.
The master server will forward this request to the payload along with the client's IP address, and the payload will try to connect to client.
On success, the payload will spawn a reverse shell with which the client can interact.

All this mess just to bypass firewalls 👍

Note

shaas is a weekend project (more like a one-day project, but oh well :^) shit happens) so don't expect it to be pretty.

BUILDING

$ git clone https://github.com/markx86/shaas.git
$ cd shaas
$ make [ARGS=VALUE]...

Build arguments for the payload executable

• TARGET_CC (defaults to gcc): the compiler to be used during the build process
• TARGET_ARCH (defaults to x86_64): the target architecture
• TARGET_SHELL (defaults to /bin/sh): the shell to be executed
• TARGET_ARGV (defaults to -i): the arguments to use when launching the shell
• TARGET_ENVP (defaults to TERM=linux): the initial environment variables of the shell
• TARGET_ARTIFACT (defaults to shaas.$TARGET_ARCH.payload): the name of the resulting executable

Build arguments for the master server

• MASTER_CC (defaults to gcc): the compiler to be used during the build process
• MASTER_ARCH (defaults to x86_64): the target architecture
• MASTER_IP (defaults to 127.0.0.1): the IP address of the server
• MASTER_TARGET_PORT (defaults to 1337): the port the server listens to for the payload connection
• MASTER_REQUEST_PORT (defaults to 6969): the port the server listens to for client connections
• MASTER_ARTIFACT (defaults to shaas.$MASTER_ARCH.master): the name of the resulting executable

Build arguments for the client executable

• CLIENT_CC (defaults to gcc): the compiler to be using during the build process
• CLIENT_ARCH (defaults to x86_64): the target architecture
• CLIENT_PORT (defaults to 4200): the port the client listens to for a connection from the payload
• CLIENT_ARTIFACT (defaults to shaas.$CLIENT_ARCH.client): the name of the resulting executable

TODO

• moar testing
• support shells other than GNU's /bin/sh
• support more architectures
• support for hostnames as master server address