Today many smartphone applications are using wireless multimedia communications and hence in wireless multimedia communications mobile phone security has become an important aspect of security issue. As Android is the most popular operating system the researchers has been extensively studied Android security. However, few works have studied mobile phone multimedia security. Here in this article, we mainly focus on security issues that are related to mobile phone cameras and video based attacks. Here we specifically discover several new attacks that may occur based on the use of phone cameras. We implement the attacks on real smart phones, and demonstrate the effectiveness and feasibility of the attacks. Furthermore, we propose a lightweight defense scheme that can effectively detect these attacks. We run these attacks along with popular antivirus software to test their stealthiness, and conduct experiments to evaluate both types of attacks. The results demonstrate the feasibility and effectiveness of these attacks.