Driver Buddy Reloaded Quickstart
Table of Contents
Installation
Copy the DriverBuddyReloaded
folder and the DriverBuddyReloaded.py
script file into the IDA plugins folder, for example:
%APPDATA%\Hex-Rays\IDA Pro\plugins\
C:\Program Files\IDA Pro 7.6\plugins\
~/.idapro/plugins/
If you use Python v. 3.x, run the idapyswitch.exe
binary (located in IDA's folder) from an admin command prompt.
NOTE: IDA SDK > v.7.5 is required in order for this script to run.
Quick Usage
To use the auto-analysis feature:
- Start IDA and load a Windows kernel driver.
- Go to
Edit -> Plugins -> Driver Buddy Reloaded
or pressCTRL+ALT+A
to start the auto-analysis. - Check the "Output" window for the analysis results.
- A
<DRIVER_NAME>.sys-YYYY-MM-DD-TIME_STAMP-DriverBuddyReloaded_autoanalysis.txt
file containing the analysis results, will be written under IDA's DB directory.
To decode an IOCTL:
- Place the mouse cursor on the line containing a suspected IOCTL code.
- Right-click and select
Driver Buddy Reloaded -> Decode IOCTL
; alternatively, press theCTRL+ALT+D
shortcut.
To decode ALL IOCTLs within a function:
- Place the mouse cursor on the first instruction of the function you believe to be the IOCTL dispatcher (
DispatchDeviceControl
,DispatchInternalDeviceControl
,Possible_DispatchDeviceControl_#
) - Right-click and select
Driver Buddy Reloaded -> Decode ALL IOCTLs in Function
; alternatively, press theCTRL+ALT+F
shortcut. - A
DriverName.sys-2021-12-10-TIME_STAMP-IOCTLs.txt
/DriverName.sys-2021-12-10-TIME_STAMP-IOCTLs.txt_dumb.txt
file, containing all the decoded IOCTLs up to that moment, will be written under IDA's DB directory.
Advanced Usage
-
The vulnerable_function_lists directory contains a lists of potentially dangerous/problematic functions, Windows APIs and opcodes; a brief description on why a specific function/API has been listed is provided. You can edit the
custom
list including driver's specific functions.Note:
winapi_function_prefixes
will partial match to start of function name (e.g.Zw
will matchZwClose
,ZwCommitComplete
and so on) whilewinapi_functions
will perform exact matches only. -
In find_opcodes.py, the
find_opcode_data
option will prevent Driver Buddy Reloaded to find opcodes in data sections. Switching it toTrue
will print something along this line:Found jnz short loc_15862 in sub_15820 at 0x00015852
Usually, going at the showed address and re-defining the selection as code will bring the searched opcode back.Watch out: switching it to
True
, will generates more false positives!
About Driver Buddy Reloaded
Driver Buddy Reloaded is an IDA Pro Python plugin that helps automate some tedious Windows Kernel Drivers reverse engineering tasks. It has a number of handy features, such as:
- Identifying the type of the driver
- Locating
DispatchDeviceControl
/DispatchInternalDeviceControl
functions - Populating common structures for
WDF
andWDM
drivers- Attempts to identify and label structures like the
IRP
andIO_STACK_LOCATION
- Label calls to
WDF
functions that would normally be unlabeled
- Attempts to identify and label structures like the
- Finding and decoding IOCTL codes
- Flagging functions prone to misuse
- Finding potential
DeviceName
- Dumping
Pooltags
Finding DispatchDeviceControl
The tool can automatically locate and identify the DispatchDeviceControl
routine. This function is used to route all
incoming DeviceIoControl
codes to the specific driver function associated with that code. Automatically identifying
this function makes finding the valid DeviceIoControl
codes for each driver much quicker. Additionally, when
investigating possible vulnerabilities in a driver due to a crash, knowing the location of this function helps narrow
the focus to the specific function call associated with the crashing DeviceIoControl
code.
When the analysis is successful some subs will be renamed as follow:
DriverEntry
: the original first driver-supplied routine that is called after a driver is loaded. It is responsible for initializing the driver.Real_Driver_Entry
: usually the function where the execution fromDriverEntry
has been transferred to. It is usually where theDeviceName
is initialized.DispatchDeviceControl
/DispatchInternalDeviceControl
: if the tool was able to recover the functions at some specific offsets, the functions will then be renamed with the appropriate name.Possible_DispatchDeviceControl_#
: if the tool was not able to recoverDispatchDeviceControl
orDispatchInternalDeviceControl
, it employs an experimental searching, following the execution flow, and checking for cases where the function is loading knownIO_STACK_LOCATION
&IRP
addresses; indicating that the function could be the DispatchDeviceControl. As it is based on heuristic, it could return more than one result, and it is prone to false positives.
Labelling WDM and WDF Structures
Several driver structures are shared among all WDM
/WDF
drivers. The tool is able to automatically identify these
structures, such as the IO_STACK_LOCATION
, IRP
, and DeviceObject
structures and can help save time during the
reverse engineering process and provide context to areas of the driver where these functions are in use.
Finding and Decoding IOCTL Codes
While reversing drivers, it is common to come across IOCTL codes as part of the analysis. These codes, when decoded, reveal useful information and may draw focus to specific parts of the driver where vulnerabilities are more likely to exist.
By right-clicking on a potential IOCTL code, a context menu option is presented (alternatively using the
Ctrl+Alt+D
shortcut when the cursor is on the line containing a suspected IOCTL code) and can be used to decode the
value. This will print out a table with all decoded IOCTL codes. By right-clicking on a decoded IOCTL code, in the
disassembly view, it's possible to mark it as invalid; this will leave any non-IOCTL comment intact.
If you right-click, alternatively using the
Ctrl+Alt+F
shortcut, on the first instruction of the function you believe to be the IOCTL dispatcher (
DispatchDeviceControl
, DispatchInternalDeviceControl
, Possible_DispatchDeviceControl_#
) under the Driver Buddy
Reloaded menu, a โDecode Allโ option appears, this attempt to decode all the IOCTL codes it can find in the
function. This is a bit hacky but most of the time it can speed things up.
- A
DriverName.sys-2021-12-10-TIME_STAMP-IOCTLs.txt
/DriverName.sys-2021-12-10-TIME_STAMP-IOCTLs.txt_dumb.txt
file, containing all the decoded IOCTLs up to that moment, will be written under IDA's DB directory.
Flagging Functions
Driver Buddy Reloaded has lists of C/C++ functions, opcodes and Windows APIs (defined in the vulnerable_function_lists directory) that are commonly vulnerable or that can facilitate buffer overflow conditions. All found instances are reported back during the auto-analysis and can help while looking for possible user-controlled code paths reaching sensitive functions.
Finding DeviceName
The tool automatically attempts to find the drivers registered device paths (DeviceName
), if no paths can be found by
looking at Unicode strings inside the binary, then the analyst can manually try to use
Madiantโs FLOSS in an attempt to find obfuscated paths.
Dumping Pooltags
During the auto-analysis, the tool also dumps the Pooltags
used by the binary in a format that works
with pooltags.txt
. The output can then be copy-pasted at the end of the file and later picked up by WinDbg.
- A
DriverName.sys-2021-12-10-TIME_STAMP-pooltags.txt
file, containing all the dumped Pooltags, will be written under IDA's DB directory.
Known Caveats and Limitations
- Only IOCTL values >=
0x10000
will be automatically decoded, thus to prevent an high number of false positives. Issue #15 - Experimental
DispatchDeviceControl
searching works only for x64 drivers - Shortcuts are incompatible with F-Secure's win_driver_plugin
- Shortcuts are incompatible with findcrypt-yara
- In find_opcodes.py, the
find_opcode_data
option will prevent Driver Buddy Reloaded to find opcodes in data sections. Switching it toTrue
will print something along this line:Found jnz short loc_15862 in sub_15820 at 0x00015852
Usually, going at the showed address and re-defining the selection as code will bring the searched opcode back. Watch out: It is prone to false positives!
Credits and Acknowledgements
- Created in 2021 by Paolo Stagno aka @Void_Sec:
- Made it compatible with Python 3.x
- Made it compatible with IDA 7.x
- Updated C/C++ function and Windows APIs list
- Various bug fixing
- Various improvements
- Integrated part of the functionalities presents in F-Secure's win_driver_plugin
- DriverBuddy was originally written by Braden Hollembaek and Adam Pond of NCC Group.
- Using Satoshi Tanda's IOCTL decoder.
- The WDF functions struct is based on Red Plait's work and was ported to IDA Python by Nicolas Guigo, later updated by Braden Hollembaek and Adam Pond.
- Using Sam Brown's F-Secure win_driver_plugin to retrieve device name and pool tags, specifically Alexander Pick fork.
- The original code for adding items to the right-click menu (and possibly some other random snippets) came from 'herrcore'.
- Prodly developed using PyCharm for Open Source development by JetBrains