In one aspect of the present description, operations are described for detecting whether programming code of a first computer program has been modified by a second computer program. In one embodiment, the modification detecting includes registering a first section of programming code of the first computer program in a first registry data structure. To detect a modification, the registered first section of programming code may be validated. In one embodiment, the validating includes comparing the section of programming code actually located at the first memory address to the registered first section of programming code. In another aspect, various selectable remedial actions may be taken upon detecting modification of programming code of the first computer program. Other features and aspects may be realized, depending upon the particular application.