Practical 8: DoS Demonstration using Colasoft Packet Builder

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PRACTICAL NO:8

DoS using Colasoft By flooding the destination with data packets


Denial of Service (DoS) is a cyber-attack on an individual Computer or Website with the intent to deny services to intended users. Their purpose is to disrupt an organization's network operations by denying access to its users. Denial of service is typically accomplished by flooding the targeted machine or resource with surplus requests in an attempt to overload systems and prevent some or all legitimate requests from being fulfilled. For example, if a bank website can handle 10 people a second by clicking the Login button, an attacker only has to send 10 fake requests per second to make it so no legitimate users can log in. DoS attacks exploit various weaknesses in computer network technologies. They may target servers, network routers, or network communication links. They can cause computers and routers to crash and links to bog down. The most famous DoS technique is the Ping of Death. The Ping of Death attack works by generating and sending special network messages (specifically, ICMP packets of non-standard sizes) that cause problems for systems that receive them. In the early days of the Web, this attack could cause unprotected Internet servers to crash quickly. It is strongly recommended to try all described activities on virtual machines rather than in your working environment.  










STEPS:
1. Download and Install Colasoft Packet Builder:
o Visit: Colasoft Packet Builder Download
o Install the software.


2. Launch Colasoft Packet Builder.


3. Create a New Packet:
o Click on ‘Add’ and choose TCP packet.
o Set Source IP Address (e.g., 192.168.0.1).
o Set Destination IP Address (e.g., 192.168.0.255 or target machine&#39;s IP).







4. Configure the Adapter:
o Click on ‘Adapter’ and select the appropriate network adapter (e.g.,
Microsoft or default Ethernet/Wi-Fi adapter).




5. Add More Packets (Optional):
o Click on ‘Add’ again and this time, choose ARP packet.
o Customize if needed and click OK.




6. Send Packets:
o Right-click in the packet list and select ‘Send All Packets’.
o Configure loop settings (e.g., loop count = 1000, interval = very low to
simulate flood).



7. Start Wireshark for Monitoring:
o Open Wireshark.
o Start a new capture session with the filter:
ip.addr==192.168.0.1 &amp;&amp; ip.addr==192.168.0.255
(Modify the IPs based on your setup)
8. Start the Attack:
o Go back to Colasoft and click Start to begin sending the packets.
o Observe the traffic in Wireshark.


9. Observation:
o Wireshark will show a high volume of TCP (and ARP if added) packets from
192.168.0.1 to 192.168.0.255.
o The destination is flooded with unnecessary traffic, simulating a DoS
scenario.

LAB SAFETY: Perform security testing only on systems, accounts, and networks you own or have explicit permission to test. Use isolated training targets and follow instructor directions.