Methods, systems, and apparatus, including computer programs encoded on computer storage media, for extracting source code. One of the methods includes receiving, by a newly created process, a request to execute code of an executable file in the newly created process, wherein the request specifies a parameter. The newly created process loads a process interception library. Library initialization code of the process interception library determines whether the parameter should be intercepted. In response to determining that the parameter should be intercepted, the parameter is provided to another process.