Recently, as Internet is widely used due to the increased spread of the internet network, the software with malicious intent is distributed via the internet and its infection path gets various too. In particular, attacks by Bot mainly work at C&C (command-and-control) server but it can be secured just by blocking IP because C&C server runs in form of IP. However, this attacker too gets gradually intelligent as they try to connect periphrastically in order to avoid server blocking. Once these malicious codes infiltrate user's system, it is not easy to detect it through general detection method while it isrunning. In this paper, we propose malicious process detection system based on security agent in order to prevent damage caused by malicious code infection from spreading.