Techniques are disclosed relating to detecting potential malware. A computer system may access process information identifying a set of software modules stored in a memory space allocated for a computer process. The computer system may determine address ranges that are respectively associated with a software module and define a segment in the memory space where program instructions are stored corresponding to that software module. The computer system may access thread information specifying, for each of a set of threads, a start address that identifies a location from which an initial program instruction is to be retrieved to begin execution of that thread. The computer system may make a determination that a thread is associated with a start address identifying a location outside of all address ranges, but within the memory space. Based on the determination, the computer system may classify the thread as being associated with malicious activity.