Systems, methods, routines and/or techniques are described to protect users from undesirable content, for example, on an open platform. One or more embodiments may prevent the installation of an application package or warn a user if the application package may be undesirable (e.g., because it may contain malware). In one or more embodiments, a method may include receiving a first request to install an application package, and receiving and/or capturing metadata related to the application package. The method may include communicating a second request (e.g., including the metadata) to a remote server, such that the remote server can determine whether the application package may be undesirable. The method may include receiving a response from the remote server, where the response may indicate whether the application package may be undesirable, and initiating installation of the application package if the application package is determined to be safe and/or acceptable.