Providing effective security mechanisms is an important requirement to any secure cloud solution. In this sense, it's proposed to use a hybrid approach to cloud security that includes both warning and detection mechanisms in order to minimize the possibility of a successful attack. According to that proposal, the customized attribute-based encryption (ABE) is a comprehensive access control solution for cloud storage services including user accountability and key revocation. The authors apply state-of-the-art signal processing techniques in order to detect the malicious activities and Man-in-the-Cloud (MITC) attacks in the cloud environment.