Drosera

Drosera is a SSH tarpit server. Inspired by endlessh.

When initiating a SSH session, the server first sends a version string to the client before communication begins. However, tarpits like drosera can exploit the following paragraph in the SSH specification, found in RFC 4253:

The server MAY send other lines of data before sending the version
string.  Each line SHOULD be terminated by a Carriage Return and Line
Feed.  Such lines MUST NOT begin with "SSH-", and SHOULD be encoded
in ISO-10646 UTF-8 [RFC3629] (language is not specified).  Clients
MUST be able to process such lines.

It is thus incredibly easy to trap ill-configured clients in a tarpit by simply never sending the version string. To keep the connection alive, some data should be sent periodically.

Drosera, like its beautiful namesake, is designed to thrive in memory-constrained environments while feeding on the numerous blood-sucking drones seeking prey on the Internet.

Table of Contents

• Installation
• Usage
• Risks

Installation

Install drosera by either grabbing a pre-built binary or by running one of these commands.

cargo install drosera
cargo install --git https://github.com/LimeEng/drosera

Usage

To view the available options and usage details, execute the drosera binary. Below is an example of the output:

Tarpit SSH server

Usage: drosera [OPTIONS]

Options:
  -s, --socket_addr <socket_addr>
          The socket address to bind to [default: 127.0.0.1:22]
  -m, --max_connections <max_connections>
          The maximum number of connections maintained at once [default: 1024]
  -d, --delay <delay>
          Approximately wait this long before sending more data (in milliseconds) [default: 10000]
  -h, --help
          Print help
  -V, --version
          Print version

Risks

Running tarpits servers at all might not be a good idea. An adversary might even be able to exploit a vulnerability in drosera to gain access to the machine it's running on. Adversaries could also launch massive denial-of-service attacks, quickly consuming what little memory is available and crashing the server.