Hello Abhishek, The problem isn't doing the attack. The problem is evaluating the effect of the attack.

Since NetSim is a discrete event simulator and application delays (i.e., the time required to process an event - is never considered, the server will be able to process all the incoming pings, TCP SYN etc. up to its internal buffers, which are nearly infinite.

So, my answer is that one cannot trust too much the results. Unless you have a deep knowledge of the NetSim DES Engine, and buffers work.

If you have any existing paper which explains the implementation of a DOS attack in a Network Simulator, one could look at that and see if something similar can be done in NetSim.

In any case you must be good in C and have a knowledge of NetSim's internal working to do the same.

This may be possible if you can add some processing delay in the IP/TCP layer for responding to the DOS attacks. This should be doable in NetSim but you should know the working of NetSim's code or you can ask their tech support team.

Dear Abhishek,

the following classes of DoS attacks can be performed on the CoAP protocol:

• The DoS attacks as a result of a malicious manipulation of the parameter ATO (Ack Time Out)

See figures 7932 and 7936 in my CoAP presentation:

https://www.researchgate.net/publication/312174308_CoAP_-_Constrained_Application_Protocol

Fig. 7932 shows that the special CoAP messages CON and ACK are transmitted on layer 5a "CoAP Messages". CON and ACK extend the "unreliable UDP transport service" to the "reliable CoAP transport service". The timeout mechanism plays an important role in this case (see Fig. 7936).

The retransmission parameters ATO and ARF can be maliciously changed - so that timeout has a relatively large value. As a result, the performance of CoAP can be influenced very strongly negatively.

For example, manipulating the MAX_RETRANSMIT parameter by setting it to 0 or 1 would also significantly reduce the performance of CoAP.

• The DoS attacks as a result of the malicious changes made by CoAP Responses.

This type of DoS Attack can be done by sending a negative CoAP Response (of type Client Error 4.xx or Server Error 5.xx) instead of a positive CoAP Response (of type Success 2.xx).

See my CoAP presentation "CoAP_Messages - Structure and Types"

https://www.researchgate.net/publication/313926805_IoT_CoAP_Messages_-_Structure_and_Types

• The DoS attacks as a result of malicious changes made by CoAP Options

For the DoS attacks, for example, you can use the options with numbers 4, 11 and 17 (4 ETag, 11 Uri-Path and 17 Accept).

The CoAP options correspond largely to the lines in the HTTP header.

See "HTTP-to-CoAP Mapping"

https://www.researchgate.net/publication/313927079_IoT_HTTP-to-CoAP_Mapping

HTTP-to-CoAP Mapping also shows that the ideas of DoS attacks on HTTP may also be "used" for DoS attacks on CoAP.

Best Regards

Anatol Badach

I recall reading about doing DDOS attack in NetSim using TCP SYN Flood. May be you can check that.

hi Piyush

is there any research paper in which DDoS implementation using NetSim is done ?