Cyberattacks targeted at virtualization infrastructure\ud underlying cloud computing services has become increasingly\ud sophisticated. This paper presents a novel malware and rookit detection\ud system which protects the guests against different attacks.\ud It combines system call monitoring and system call hashing on the\ud guest kernel together with Support Vector Machines (SVM)-based\ud external monitoring on the host. We demonstrate the effectiveness\ud of our solution by evaluating it against well-known user-level\ud malware as well as kernel-level rootkit attacks.\ud Keywords—virtualization security, cloud security,