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sshd-honeypot

The sshd-honeypot is a modified version of the OpenSSH deamon that forwards commands to Cowrie where all commands are interpreted and returned. The sshd-honeypot is designed to let Cowrie log brute force attacks and the shell interaction performed by the attacker. As the sshd-honeypot uses OpenSSH, it can not be fingerprinted based on protocol deviations or differences in error messages [1].

+------------+     +-------------+     +------------+  
|  Attacker  |<--->|sshd-honeypot|<--->|   Cowrie   |  
|            |     |  (OpenSSH)  |     |            |  
+------------+     +-------------+     +------------+

[1] Bitter Harvest: Systematically Fingerprinting Low- and Medium-interaction Honeypots at Internet Scale,
Proceedings of the 12th USENIX Workshop on Offensive Technologies (WOOT ’18) [PDF]

Installing the sshd-honeypot

Step 1: Install cowrie-sshd
Step 2: Install dependencies
Step 3: Checkout the code
Step 4: Run the installer
Step 5: Start the honeypot

Step 1: Install cowrie-sshd

First we need to install cowrie-sshd. Cowrie-sshd is a modified version of Cowrie which functions as backend for the sshd-honeypot to interpret commands and log interactions performed by the attacker.

Step 2: Install dependencies

On Debian based systems:

$ sudo apt-get install build-essential gcc libssh-dev

Step 3: Checkout the code

$ git clone https://github.com/amv42/sshd-honeypot
Cloning into 'sshd-honeypot'...
remote: Counting objects: 744, done.
remote: Compressing objects: 100% (661/661), done.
remote: Total 744 (delta 78), reused 739 (delta 76), pack-reused 0
Receiving objects: 100% (744/744), 1.76 MiB | 0 bytes/s, done.
Resolving deltas: 100% (78/78), done.
Checking connectivity... done.

$ cd sshd-honeypot

Step 4: Run the installer

The installer will populate all necessary files and configure/install the sshd-honeypot in the current working directory.

$ ./install.sh

Step 5: Start the honeypot

$ cd openssh-7.3p1
$ ./start.sh

By default, the sshd-honeypot will listen on all available IPv4 addresses on port 65222. This can be modified in the sshd_config. The following firewall rule will forward incoming traffic on port 22 to port 65222.

$ sudo iptables -t nat -A PREROUTING -p tcp --dport 22 -j REDIRECT --to-port 65222

The sshd-honeypot will connect to Cowrie on 127.0.0.1:65522. You can modify the IPv4 address and port in the sshd_config.