A Taxonomy of Buffer Overflows for Evaluating Static and Dynamic Software Testing Tools*

A taxonomy that uses twenty-two attributes to characterize Cprogram overflows was used to construct 291 small C-program test cases that can be used to diagnostically determine the basic capabilities of static and dynamic analysis buffer overflow detection tools. Attributes in the taxonomy include the buffer location (e.g. stack, heap, data region, BSS, shared memory); scope difference between buffer allocation and access; index, pointer, and alias complexity when addressing buffer elements; complexity of the control flow and loop structure surrounding the overflow; type of container the buffer is within (e.g. structure, union, array); whether the overflow is caused by a signed/unsigned type error; the overflow magnitude and direction; and whether the overflow is discrete or continuous. As an example, the 291 test cases were used to measure the detection, false alarm, and confusion rates of five static analysis tools. They reveal specific strengths and limitations of tools and suggest directions for improvements.