Results 1 to 2 of 2

Thread: Fuzzing device drivers.

  1. #1
    rckm
    Guest

    Fuzzing device drivers.

    Hi.

    It's not exactly about RE, but I think here is a good place to ask since a lot of you guys like exploitation and vulnerability development.

    I'm interested in learn more about fuzzing windows device drivers.

    I'm using the great IOCTL Fuzzer from Esagelab and I followed this tutorial:

    http://www.woodmann.com/forum/entry.php?183-Device-Drivers-Vulnerability-Research-Avast-a-real-case

    So, I started trying it myself and I have a few questions, and help from more experienced is very welcome.

    I used the fuzzer in monitor mode and I got a few entries and created a config.xml file.

    1) I noted a thing that sounds strange to me, I see a lot of
    third-parties apps calling \SystemRoot\System32\drivers\afd.sys, that is a Windows core file. So I got curious, when you see a entry like that you fuzz? I believe not, since it's a driver from Microsoft it
    should be very well audited and would not let me to find any flaw on the third-party software, right?

    2) There is a way that a device driver is vulnerable during tests with IOCTL Fuzzer, but the trigger may not happen in normal circumstances with restricted user? I mean, IOCTL Fuzzer has a device driver, so it may send any request to the device driver we are testing. There are any kind of ACL (access control list) that are imposed by Windows or may be imposed by the own device driver to only allow certain process to communicate with it? How common it's?

    3) In general do you turn <fuze_requests> to true? And <fuze_size> too? There are any special advise to turn them on, etc?

    4) Probable the most hard is to find exactly what IRP message triggered the BSOD. What do you do in average to detect the exactly sent request that triggered the issue? I checked the file ioctls.txt, but I'm a bit unsure if the last entry is the one that triggered the BSOD. What is your experience with that?

    Also, I noted a few enter (\r\n) on the end of ioctls.txt, but opening it in wordpad shows it as very strange characters (non printable).

    Ideas?

    5) I used !exploitable and it tells UNKNOWN. On the nice article that I referenced the example sounds a bit
    more easy then mine, you have a lot of 0x42 (A) in the debugger when it crashes, on mine not, mine has nothing like that and my last request at ioctls.txt are preety small without a sequence of A, that's why I believe it was not logged or it's not the last request.

    All answers and help are very welcome.

    Thanks and sorry for dumb questions.
    I promise that I have read the FAQ and tried to use the Search to answer my question.

  2. #2
    Teach, Not Flame Kayaker's Avatar
    Join Date
    Oct 2000
    Posts
    4,114
    Blog Entries
    5
    Hi

    Hopefully someone can answer your questions. I've wanted to play with that fuzzer myself but never found the time.

    I just wanted to mention that Microsoft has it's own IOCTL fuzzer, called Device Path Exerciser. It's in the tools directory of the DDK, variously called devctl.exe, dc2.exe or devpathexer.exe in the latest version.

    http://msdn.microsoft.com/en-us/library/ff544851(VS.85).aspx

    You might find more general info on driver fuzzing searching for examples of usage of the MS resource (searching for the keywords I highlighted in bold above, as well as the MSDN link), rather than the Esagelab version.

    Kayaker

Similar Threads

  1. PDF Fuzzing Fun Continued: Status Update
    By j00ru vx tech blog in forum Blogs Forum
    Replies: 0
    Last Post: January 8th, 2013, 19:41
  2. Linux device driver
    By robert in forum Linux RCE
    Replies: 15
    Last Post: April 14th, 2011, 14:00
  3. How to directly talk to USB device?
    By cEnginEEr in forum Advanced Reversing and Programming
    Replies: 7
    Last Post: June 3rd, 2009, 09:44
  4. using HID device in Driver and strange device corruption
    By Hero in forum Advanced Reversing and Programming
    Replies: 2
    Last Post: February 17th, 2008, 00:30
  5. Visual Patterns for File Format Fuzzing
    By OpenRCE_jms in forum Blogs Forum
    Replies: 0
    Last Post: November 24th, 2007, 18:50

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •