Immunology inspired computer security has attracted enormous attention as its potential impacts on the next generation service-oriented network operation system. In this paper, we propose a new agent-based threat awareness assessment strategy inspired by the human immune system to dynamically adapt against attacks. Specifically, this approach is based on the dynamic reconfiguration of the file access right for system calls or logs (e.g., file rewritability) with balanced adaptability and vulnerability. Based on an information-theoretic analysis on the coherently associations of adaptability, autonomy as well as vulnerability, a generic solution is suggested to break down their coherent links. The principle is to maximize context-situation awared systems' adaptability and reduce systems' vulnerability simultaneously. Experimental results show the efficiency of the proposed biological behaviour-inspired vulnerability awareness system.