Questions tagged [windbg]

A graphical stand-alone multipurpose debugger for Microsoft Windows, distributed on the web by Microsoft.

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Windbg memory access error when trying to edit a string value of a button

So i was trying to edit the string value of a button as a debugging practice using windbg. I'm still a complete novice in reverse engineering and debugging, when i try to edit the string value using ...
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48 views

Why is process object is shown as desktop object in nt!_object_type

I try to extract the object type of notepad.exe in windbg but the nt!_object_type is showing it as Desktop object instead of Process object. Any idea why is it so? 4: kd> !process 0 0 notepad.exe ...
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Windows time travel debugging performance bottleneck

First of all I wan to be clear, that this question is not about the collection performance, but indexing performance. What is the performance bottleneck of the indexing step? Some context: Action in ...
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How to search for process by name with WinDBG

I know how to list all the processes in the system by running: 0: kd>dx -r1 Debugger.Sessions[0].Processes OR 0: kd>.tlist But how can I search for a process by name? I tried to use the ...
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27 views

Can't resolve a function from a process module (user32.dll): “Couldn't resolve error at '<module>!<function>'”

I have a WinForm project in C++. I attached a kernel debugger to my VMware machine. I set a breakpoint on the kernel and switched context to my application: 0: kd> !process 0 0 WindowsProject1.exe ...
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35 views

Nice way to get Windows API call arguments in WinDBG

How do I get a nice list of call arguments for well documented functions such as kernel32!CreateRemoteThread in windbg? Right now when a breakpoint hits I manually decode them considering the ...
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1answer
48 views

Can't debug process with IDA Windbg debugger: “Could not initialize WinDbg engine with error: %1 is not a valid Win32 application”

I tried to debug a C++ that I created but I am getting the following error: I have this C:\Program Files (x86)\Windows Kits\10\Debuggers\x64 in the PATH environment variable (based on this answer), ...
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43 views

Why rundll32.exe could be loading a DLL multiple times?

Since I started reverse engineering I've found multiple DLLs that when being debugged(IDA + WindDBG) would be unloaded and reloaded continuously without any evident reason. Most of the time I use ...
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Whats the difference between a MiNotMapped PFN entry with all 1s, and a MiNonCached PFN entry with all 0s and a 0 PteAddress?

On host (UEFI legacy mode): lkd> !pfn 0xf0 PFN 000000F0 at address FFFFFA8000002D00 flink FFFFFFFFFFFFFFFF blink / share count FFFFFFFFFFFFFFFF pteaddress FFFFFFFFFFFFFFFF ...
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61 views

Reverse engineer sticky notes to allow external script to open new notes

For a silly little project I wanted to do, I wanted to make it so that I could open new notes (Microsoft Sticky Notes) from a external script - preferably python. Although I'm not good at reverse ...
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41 views

Local KD — can't access physical address 0xFFFFFFF0 but you can with RwEverything

I've never been able to access 0xf0000000 range using !db on local debug, and I've tried !db -m 00000000`fffffff0 and !db [uc] 00000000`fffffff0. I only get Physical memory read at fffffff0 failed. It ...
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49 views

How much of the kernel does remote kernel debugging allow you to debug?

This is a theoretical question because I've never set up remote kernel debugging before -- but I will do at some point, which should hopefully answer some of the experimental questions I have. What ...
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63 views

kd live local debugging !pte and db don't work (only shows context of the debugger for all contexts), but !vtop works

Says the PDPT and PDs of the process are at the same physcial frames (pfns) in both processes. The first process is winword.exe and the second process is calc.exe The virtual address in the first case ...
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25 views

Defining frame manually windbg

I wonder why defining frame manually keeps failing on range error. As far as I understand the syntax is : .frame /c = BASE STACK RIP where if inside MyFunc there is a call OtherFunc, the RIP should ...
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17 views

How to pause a kernel debugee instead of stopping in IDA pro?

While debugging windows kernel with IDA, the problem is i cannot pause it like Windbg, when its running and i click on suspend, 50% of times it just freezes/crashes, and other times it just gets stuck ...
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237 views

How to find encrypted strings in an executable?

I am trying to reverse engineer an executable. I am using Process explorer to dump all strings present in the exe image, and from the process's RAM when it is running. The two dumps return a ...
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1answer
149 views

WinDBG Hung on Shellcode Execution

I've been trying to debug a piece of simple shellcode with Windbg. To go over the steps I took, I allocated a buffer for the shellcode with .foreach /pS 5 ( register { .dvalloc 400 } ) { r @$t0 = ...
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1answer
52 views

Windbg .thread command is useless?

The ".thread" command is used to change the thread context in Windows kernel debugging. MSDN But I encountered the below situation: Execute the following two commands consecutively. The ...
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61 views

Is there an easier way to break on a rootkit driver load, other than disassembling IopLoadDriver?

The only method i know to break on a DriverEntry of a rootkit driver when its loaded is to disassmble nt!IopLoadDriver and find an indirect call in it and break on it. Setting a break point on ...
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39 views

How to set breakpoint on CreateThread in windbg preview

I have open an executable in Windbg Preview but when I wanted to set a breakpoint on the calling location of the CreateThread API, windbg couldn't resolve the symbol. I have reloaded all symbols for ...
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177 views

WinDBG doesn't resolve function names when debugging kernel module

I am debugging a kernel driver. When I set a breakpoint with WinDBG in one of its functions but it doesn't complete the function names while on IDA it shows the names (statically). Here is a picture ...
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95 views

Trying to reverse engineer CmpFindNlsData of winload

I have a basic understanding of assembly language and I'm unable to perfectly define the algorithm of winload!CmpFindNlsData looking at the disassembly. Basically I need to understand how NLS data is ...
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51 views

Connection to Microsoft Symbol Server reset in windbg

I'm using windbg version 6.12.0002.633 X86 on Windows XP SP3 in a VM. I've configured the environment variable, _NT_SYMBOL_PATH as shown below: _NT_SYMBOL_PATH=symsrv*symsrv.dll*c:\symbols*http://msdl....
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Is there an event log to check when WinDbg kernel debugger fails to attach on OS load?

I'm using the latest WinDbg (Preview) to do kernel debugging on a Windows 10 client (v 1909) via a network connection in a VM. And I'm wondering if there's a log that the kernel debugger maintains? I ...
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27 views

WinDbg pattern search not returning expected result

I'm searching for a string, say the old "This program cannot run". Switching context to e.g. notepad, non invasive, with page translation 1: kd> !process 0 0 notepad.exe PROCESS ...
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Find the caption of VB5/6 Form Object in Memory Dump

I'm looking at a problem with app that has lost source code and the app crashes shortly after calling code that appears to be [Global Variable representing Form Object].ZOrder 0 (i.e. trying to make ...
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49 views

bad memory mapping in case of MEMORY dump IDA <-> WinDbg

when I open the debug dump (IDA x64) , I don't have the memory ranges. Exactly like in this question: ESP out of range of "Stack View" in IDA It used to be fine, but I don't have the menu ...
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1answer
146 views

Get return address from syscall

I'm debugging some 32-bit process using windbg kernel debugger. This process calls some syscalls, so I set few breakpoints at kernel functions like nt!NtQuerySystemInformation. So after breakpoint hit,...
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203 views

Windbg: “gu” command inside of a breakpoint causes warning

I'm trying to leverage "gu" command in a conditional breakpoint or as a "CommandString" in a regular breakpoint. For example let's consider break on a malloc() function when we want to see in logs ...
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1answer
237 views

Getting NTSTATUS 0xC0000022 when attempting to debug a process

I am attempting to debug a process with windbg (with admin privileges) and I am getting the following error: Could not attach to process XXXX =, NTSTATUS 0xC0000022 {Access Denied} A process has ...
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631 views

How to calculate the size of a PE from headers?

What I am trying to do is calculate the size of a PE through it's headers. I am using WinDbg's Javascripting and in this case, it will mostly be for drivers. The idea is to dump a driver from memory ...
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111 views

How to find each interrupt's line in the Interrupt Descriptor Table

I'm trying to find the line number of the 0f05 syscall interrupt with no success. I searched everywhere and couldn't find any way of doing that, it seems like this information is hard coded in the ...
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195 views

Disassembling only given function

I'm looking for some disassembler that has feature similar to WinDbg uf function, it produces output that is really easy transferable to compilable NASM listing. The problem with WinDbg is that it's ...
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164 views

Issues with Symbols when running windbg on windows xp sp3

I have been trying to debug a crash using windbg on windows xp sp3. I have been getting the below error while trying to debug. I googled around and found the Microsoft no longer offers symbols exe as ...
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618 views

Remote debugging using IDA, connecting to windbg server (kernel mode)

I do kernel debugging by using a virtual com port. One machine (host) is debugging the other machine. I have a remote machine that has IDA, and I wish to connect to the debugging session in the host ...
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82 views

Predicting Memory locations of arguments within a function

I'm trying to write a script that would help display the memory contents of the arguments passed within a function. For example, in the function below, the first argument starts at the EAX register. ...
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1answer
52 views

What does -c mean in this Windbg Command Syntax?

kd> u win32k!impPsIsThreadTerminating+0xe4-c L5 | \ \ \ \ \ / \ \ \ \ \ / \ \ \ \ \ ...
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1k views

x64dbg (x32dbg) log registers every step like windbg

So I just switched to x64dbg (really using x32 atm) from windbg and so far I like it but the one thing I'm missing is windbg printing all the registers every step in the command window. Anyone know ...
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254 views

Setting a conditional kernel breakpoint in WinDbg grinds the debuggee OS to a halt

My setup: Debugger: Win10 Pro, WinDbg Preview v.1.0.1904.18001 Debuggee: Win7 Pro (running in a VM using VMWare Workstation) I'm trying to follow the SendMessage call from the user space: Into the ...
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1answer
6k views

How to configure IDA to load .pdb files from Microsoft public symbol server?

I've done this in one VM but I can't seem to replicate it in another. I'm using IDA to analyze a 32-bit Windows PE file. I then want to step thru it with a WinDbg debugger from within IDA. So when I ...
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1answer
172 views

How to call WinApi from a breakpoint in IDA Pro?

When I'm stepping through a debuggee process with IDA+WinDbg (as a debugger), I need to track one parameter by executing the following API (from within the breakpoint): //C++ code SCROLLINFO s; s....
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400 views

Analyzing Windows kernel driver

I'm trying to analyze some Windows kernel driver. What I want to achieve is full execution trace, from driver entry to end point. Driver is heavily virtualized and contains multiple anti-debugging ...
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57 views

WinDbg does not shows all first chance exceptions

I have an application, which sometimes fails. I run procdump and see some first chance exceptions like this: [14:29:38] Exception: E06D7363.?AVCServicesMDException@@ [14:29:38] Exception: E06D7363.?...
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1k views

windbg - Why does the GS register resolve to offset 0x0?

I'm trying to understand how to resolve segment addressing (specifically the GS register in X64). My toy program: int main() { unsigned long long x; __debugbreak(); x = __readgsqword(...
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842 views

windbg - What is the relation between the VAD (!vad), the PTEs (!pte), and loaded modules and sections (lm and !dh)?

[cross-posted (but closed the original) from https://stackoverflow.com/q/55438806/254959] I'm trying to gain a better understanding on Windows process memory, and have some gaps with regards to the ...
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710 views

Detecting protected processes and critical processes from windows driver

I've got a driver that tamper user-space processes by sending APC calls upon process start using the call PsSetCreateProcessNotifyRoutine. I wish to avoid tampering with any process that is critical ...
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1answer
727 views

How to use windbg to view assembly code of kernel function?

I am using windbg for local kernel debugging. I want to view the disassembly of a kernel function (eg. AuxKlibQueryModuleInformation). I am not familiar with kernel debugging. Please help me do this.
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1answer
834 views

Debugger Win32 Local vs WinDbg in Ida vs Ollydbg

When I do dynamic analyze of exe file I have few option , and I want to know what are the advantages and disadvantages. I know that Ida designated for static analyze , but there are some debugger in ...
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1answer
179 views

Why IDA can't find the function named by windbg

This is definitely a beginner question,I'm doing static and dynamic analysis on certain dll file and the WinDbg give me call stack like SERVER+0x78123 When I return back to IDA to see the code ...
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1answer
75 views

Windbg Break Points

I need to set a break point when a specific module address space is being overwritten? I need to specify this by module name not address space