If you experience a denial-of-service attack, you can use firewall logs to determine the from which the attack originated.

IP Address

Explanation:

Denial of service (DOS) attack is basically occur when the multiple system and the web servers are flooded with the bandwidth and the system resources. If the system are flooded with the traffic then it cause the denial of service attack. Botnet is one of the example of DOS.

When we experiencing the DOS attack then, we used the firewall logs for determine the origin of attack by using the IP address. IP address is the internet protocol that uses for the communication purpose.The IP address is in the form of numerical label that assigned to the every network devices  for the communication. The main function of the IP address is that it is used for the location addressing.

 

Malware, not sure what else would fit that description.