On this weblog sequence, I will probably be placing the highlight on helpful Ghidra options you could have missed. Every submit will have a look at a special function and present the way it helps you save time and be more practical in your reverse engineering workflows. Ghidra is an extremely highly effective device, however a lot of this energy comes from figuring out find out how to use it successfully.
On this submit, I will probably be discussing what slice highlighting is and the way it helps us visualize relationships between variables to higher perceive a program. Earlier than we will focus on find out how to use slice highlighting in Ghidra, I’d wish to take a second to introduce the idea of program slicing. When it comes to software program reverse engineering, program slicing is a approach of abstracting code into smaller teams of statements generally known as slices. Slices are fashioned by following how a selected variable’s worth impacts or is affected by the values of different variables. The Ghidra Decompiler exposes performance to rapidly apply highlighting to visualise these program slices.
The best technique to entry slice highlighting inside Ghidra is to right-click on a variable within the Decompiler:
It is very important notice that the slice highlighting choices are solely out there when the cursor is at a variable whose worth is getting used or set. Slice highlighting is just not out there within the context menu if the cursor is at a variable declaration or a program level the place the deal with of operator (&) is getting used. The Spotlight Ahead Slice motion will spotlight variables whose values are affected by the worth of the variable underneath the cursor.
Within the above instance, a ahead slice was requested for index on line 31. Be aware that on line 31, the utilization of floor_area wouldn’t be affected by index till after the loop restarts.
Spotlight Backward Slice will spotlight variables whose values contributed to the worth of the variable underneath the cursor.
Within the above instance, a backward slice was requested for index on line 31. The one highlighted variable on this case is index, and it contains the initialization of index previous to getting into the loop.
Along with these choices, Ghidra additionally has ahead and backward ‘Inst Slice’ choices. That is quick for instruction slice and can embrace all directions that have an effect on or are affected by the worth of the variable underneath the cursor.
Within the context of vulnerability analysis, slice highlighting offers a technique to rapidly establish the scope of management an attacker has after they management a selected variable or alternatively which variables they would wish to regulate to affect the worth of a variable.
Learn Extra about Ghidra
Ghidra 101: Cursor Textual content Highlighting