Analysis with Visual Mode

Static and Dynamic Analysis in Visual Mode.

Using Visual Mode, we can more easily perform static and dynamic analysis on a binary. This section will discuss two modes that are commonly used to analyze functions and then debug the binary.

Visual Debugger Mode

Visual Debugger Mode is an immensely powerful tool for static and dynamic analysis of a binary. This mode shows us the instructions, stack, and registers at a seek address. We can also use this mode to run the binary and debug it.

Navigation

Visual Debugger Mode offers a few ways to navigate the binary. Below are the standard navigation commands for Visual Debugger Mode. These commands directly influence the current seek address.

• $\uparrow$ / j - Move the seek address forward one instruction.

• $\downarrow$ / k - Move the seek address back one instruction.

• $\leftarrow$ / h - Decrease the seek address by one byte.

• $\rightarrow$ / l - Increase the seek address by one byte.

The most common way to navigate is to use j and k to move between instructions. Moving one byte at a time isn't very useful.

There are a few other useful navigation commands. These are:

• $.$ - Seek to $eip

• c - Show/hide the cursor. This is useful for labeling commands like comments.

• Enter - Seek into the current function. This is useful for navigating across the binary and resolving functions.

• u - Undo the last seek maneuver. This is used in conjunction with Enter to return to the calling function.

• g / G - Seek to the beginning/end of the binary.

• x - Show cross-references to the current seek address. This is useful for finding functions that call the current function.

When you use the . command, references will be renamed in terms of eip. Using the s command to move elsewhere resets this.

Entering Commands

When inside Visual Debugger Mode, use the : command to open the command line. Like Vim, this opens a small command line at the bottom of the window to enter commands.

Once you enter a command, another command line shows to enter another command. To exit this, use Enter again to leave the command line environment.

The Visual Debugger Mode frame will not reset until the command line is exited. Therefore, when using commands like s that actively change location, ensure you exit the command line to register the new location.

Dynamic Analysis

Unfortunately, we don't have a shortcut to set breakpoints in Visual Debugger Mode automatically. However, using the : command, we can set breakpoints using the db command. We also don't have a shortcut to continue to this breakpoint, so we use :dc to continue to the breakpoint.

Once we do this, we will see our instruction pointer at the start of main.

Running Binary in Visual Debugger Mode

We can use the following shortcuts to step through the binary:

• s - Step into the current instruction.

• S - Step over the current instruction.

We can use these to quickly step through the binary and watch the registers and stack.

My current version of radare2 freezes every time I step over a gets instruction. I'm not sure why this is. The only mitigation I have found is to close Visual Debugger Mode before stepping over this instruction.

Visual Code Analysis

Visual Code Analysis is a somewhat hidden feature of Visual Mode. This mode mimics using pdf on the command line to show us disassemblies for all functions.

To enter this mode, use Vv from the command line or press v from anywhere inside Visual Mode.

Radare2 Visual Code Analysis

You can use the up and down arrows (or j and k) to navigate between functions. You can use the Enter key to seek to that function.

There is a lot of functionality within this pane to modify functions. However, we don't cover write mode in this guide.