When a program is loaded for execution, all code pages of the program except the one containing the entry point are set to be non-executable. When the executing program attempts to jump between code pages, an exception is thrown. Responsive to such an exception, a control flow graph of the program is examined, to determine if the attempted jump between code pages is expected. If the attempted jump is not expected, it is determined that the program is attempting a malicious activity. If the attempted jump is expected, the code page to which the program is attempting to jump is set to be executable, and control is returned to the program such that the jump executes.