Objectives: Cloud computing technology is in continuous development, and with numerous challenges regarding security. In this context, one of the main concerns for cloud computing is represented by the trustworthiness of cloud services in the Pakistan Information Technology (IT) industry. This problem requires prompt resolution because IT organizations in Pakistan adopting cloud services would be exposed to increased expenditures while at a higher risk. A survey conducted by International Data Corporation (IDC) in August 2008 confirms that security is the major barrier for cloud users in Pakistan. Material/methods: We have proposed the mathematical-based model for an estimate of our user's requirements regarding our resource investment based on queuing theory to overcome these security issues in cloud technology. We are adopting a system and real-world analysis using data set experiments. Result: In this article, we proposed a solution to overcome the Distributed Denial of Service (DDoS) attacks in a cloud computing environment in the Pakistan IT services; because along with discussed above phenomena, we also used DST and FTA (Fault Tree Analysis) for mentioned attacks. Conclusion: Our proposed solution based on Dempsters combination rule is to analyzed mixture proof of different types of cloud attacks in IT industries in Pakistan.