Method and agent for preventing a hostile use of computer resources by an application running on a workstation. A list of services that are not allowed for access by unspecified applications is determined, and when such unspecified application runs on the workstation, direct access to the application is prevented from any resource. Any direct or indirect request for access to specific services is analyzed, to determine whether such request is allowable according to the list. The workstation processes the request if it is allowable. The unspecified application is prevented from accessing the requested resource if the request is not allowable. The resource may be any local or remote resource, such as, memory allocation, files, directories, operations with files and directories, such as copy, delete or compress, or any other operation leading to a permanent change in the workstation or its periphery. A look-up table which includes a list of services that are not allowed for access by unspecified applications, is used to determine whether requests made directly or indirectly by the unspecified application are allowable. The agent comprises a pre-set list of applications including a list of resources that each application may utilize.