US Patent 10089461 Page replacement code injection

Techniques for malicious content detection using code injection are described herein. In one embodiment a first code section of a target program is loaded into a first memory page of a virtual machine (VM) hosted by a virtual machine monitor (VMM). The target program to receive code injection. The VMM injects a second code section into the target program by replacing the first code section with a second code section loaded in a second memory page. Determining a behavior of a content specimen using the injected second code section instead of the first code section, and the second code section is injected after the target program.