Security Checks only happen when you have passed your medical exams.
At this point in time, as Mr. Qorax has said, it is the background check that the visa office is doing on your application i.e. your application is in process.
After your background checks are complete and documents verified and the visa officer decides that you fit the bill for a Canadian PR card, the visa office will send you the medical forms to complete an immigration medical examination. Once you receive medical request, you can be sure 99 percent that your application is approved. IF you pass tme medical exam, then the security checks begin on your application. This is done by CSIS, not by the visa office. It may take anywhere between 3-5 months, sometimes more if necessary. In short, your application is in process, neither approved nor rejected.