Yersinia is a network tool designed to take advantage of some weaknesses in different network protocols. It pretends to be a solid framework for analyzing and testing the deployed networks and systems.

Attacks for the following network protocols are implemented: Spanning Tree Protocol (STP), Cisco Discovery Protocol (CDP), Dynamic Trunking Protocol (DTP), Dynamic Host Configuration Protocol (DHCP), Hot Standby Router Protocol (HSRP), IEEE 802.1Q, IEEE 802.1X, Inter-Switch Link Protocol (ISL), VLAN Trunking Protocol (VTP).

Attacks using DHCP Starvation, which exhausts all IP Pool DHCP server.The operating principle of this attack is very simple:

• Asking yourself IP -address at the DHCP server and a receives it;
• Change the MAC addresses and ask for the next one, a different IP -address, masquerading as a new client;
• Such action is repeated until the entire pool of IP address on the DHCP server is reached.

To automate this type of attack there is a tool called Yersinia

Features:

• 100% written in C.
• It uses libpcap, libnet and ncurses.
• Runs on Linux, BSD and Solaris, Mac OSX
• Multithreaded: it supports multiple users and multiple attacks per user.
• Examine, analyze and watch your packets
• Edit each protocol’s fields
• Capture your network data in pcap format.
• Customize your preferences in a configuration file.
• Monitor and capture packets from the network and replay them with your modifications.
• Three main modes: command line, network client and ncurses GUI

Usage:

yersinia [-hVGIDd] [-l logfile] [-c conffile] protocol [protocol_options]

-V   Program version.
-h   This help screen.
-G   Graphical mode (GTK).
-I   Interactive mode (ncurses).
-D   Daemon mode.
-d   Debug.
-l    logfile   Select logfile.
-c   conf-file  Select config file.

Once you have git cloned and installed Yersinia lets run it

yersinia –I

press I and select the required interfaces.

press g  and select the DHCP.

press x, to select an attack ( eXecute attack ) and select Punk 1 – Sending DISCOVER packet.

The attack started.

To stop the attacks press l, select the active attack and press the Enter.