In recent years, physical and virtual machines are heavily threatened by malwares. Deploying traditional detection tools such as anti-virus softwares and firewalls on Infrastructure as a Service (IaaS) cloud faces the following problems:1) detection tools may be damaged or shut down by malwares; 2) the detection rate of a single tool is insufficient; 3) detection tools are easily bypassed; 4) it's difficult to deploy additional softwares in each virtual machine. A diversified malware detection framework was proposed to overcome these shortcomings. The framework leveraged virtualization technology to intercept some specific behavior of virtual machines at first. Then codes from virtual machines' memory were extracted dynamically. Finally, several anti-virus softwares were used to codetermine whether the extracted codes were malicious or not. The extraction and judgment processes were totally transparent to virtual machines. A prototype was implemented based on the Xen hypervisor and some experiments were done. The prototype has a malware detection rate of 85.7%, which is 14.3 percentage points higher than static anti-virus softwares. The experimental results show that the diversified malware detection framework on cloud platform can provide more effective protection to the security of virtual machines.