Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for monitoring the generation of link files by processes on a computer and performing protection processes based on whether the link files target malicious objects or are generated by malicious processes. In one aspect, a method includes monitoring for a generation of a first file that includes a target path that points to an object; in response to monitoring the generation of the first file: determining whether the target path is a uniform resource locator; in response to determining that the target path is a uniform resource locator, identifying a process that caused the first file to be generated; determining whether the process is a prohibited process; in response to determining that the process is a prohibited process, performing one or more protection processes on the process and the first file; in response to determining that the process is not a prohibited process, determining whether the uniform resource locator is a prohibited uniform resource locator; in response to determining that the uniform resource locator is a prohibited uniform resource locator, performing one or more protection processes on the process and the first file.