IoT devices depend on a network for communication and convenient information sharing. However, networks suffer from security threats such as DoS attack, RPL attack. We propose a honeypot-based method to detect such attacks. In proposed solution, Cowrie honeypot is used to capture adversaries activities. Captured unlabeled data is analyses by a modified Naive Bayes algorithm in combination with K-means clustering approach. Proposed solution effectively identifies DoS attacks and helps to strengthen the firewall and intrusion detection system functionalities.