The complexity, multiplicity, and impact of cyber-attacks have been increasing at an alarming rate despite the significant research and development investment in cyber security products and tools. The current techniques to detect and protect cyber infrastructures from these smart and sophisticated attacks are mainly characterized as being ad hoc, manual intensive, and too slow. We present in this paper AIM-PSC that is developed jointly by researchers at AVIRTEK and The University of Arizona Center for Cloud and Autonomic Computing that is inspired by biological systems, which can efficiently handle complexity, dynamism and uncertainty. In AIM-PSC system, an online monitoring and multi-level analysis are used to analyze the anomalous behaviors of networks, software systems and applications. By combining the results of different types of analysis using a statistical decision fusion approach we can accurately detect any types of cyber-attacks with high detection and low false alarm rates and proactively respond with corrective actions to mitigate their impacts and stop their propagation.