21
votes
Accepted
OllyDbg vs x64dbg - Does OllyDbg have any particular advantage over x64dbg?
Debugging software with a combination of managed and unmanaged code:
Ollydbg debugs and runs managed code very well (of course in this case it only runs as a native debugger and not like DnSpy which ...
- 226
14
votes
OllyDbg vs x64dbg - Does OllyDbg have any particular advantage over x64dbg?
Disclaimer: I am the main developer of x64dbg, take that into account :)
I would say that the main difference between OllyDbg and x64dbg is that there is no 64 bit (os) support at all in OllyDbg. If ...
- 1,652
10
votes
Accepted
Trace back which function called the message box in x64dbg?
You can find this out by first running the program to the entry point to skip all of the boilerplate code, then go to the Symbols tab in x64Dbg, going to User32.dll and then filtering for the ...
- 1,830
10
votes
Accepted
How to view string references?
When x64dbg attaches to a process it will first stop at the 'Attach breakpoint'. The button to search for string references will search the module currently shown in the disassembly. To search in ...
- 1,652
10
votes
Accepted
How does this EB F2 x86 instruction work?
from google starmans realm
quoting relevant info
These are also known as SHORT Relative Jumps. Programs using only Relative
Jump instructions can be relocated anywhere in memory without ...
- 16.3k
9
votes
Displaying IDA names in x64dbg or OllyDbg
The plugin labeless (https://github.com/a1ext/labeless) was created for exactly this purpose. You can now also use x64dbgida (https://github.com/x64dbg/x64dbgida) to import/export x64dbg databases.
- 1,652
8
votes
Dealing with exceptions in x64dbg
Exceptions are complicated business. I will attempt to explain briefly how SEH (Structured Exception Handling) in Windows works to invoke the appropriate exception handler. Your game probably does not ...
- 141
8
votes
Accepted
Search strings in multiple files/processes/modules (x64dbg)
From what I know you can search for String references in all modules.
The way is: right click ---> search for ---> all modules ---> String references
- 355
7
votes
How to break when specific text is found
You are searching for Conditional Breakpoints
OllyDBG
It's possible to set a conditional breakpoint in both OllyDbg 1.01 and 2.00
Conditional Breakpoint
Displays dialog window asking user to ...
- 8,919
7
votes
Tracing function calls in x64dbg
It is possible using Trace->Trace into... option. After opening the executable, select this option and specify the message you want to log (in Log text field); for example {a:cip} {i:cip}, which ...
- 3,369
7
votes
Debug a windows service entry without windbg
I'll post my own answer here so I can find this again in the future.
Using CFF Explorer open the service binary.
Find the AddressOfEntryPoint in the Optional Header.
Find the .text entry in Section ...
- 422
6
votes
How can i add plugins in x64dbg?
Download
Download the files
apis_def.zip
xAnalyzer.dp32
xAnalyzer.dp64
from
here
Steps
Copy xAnalyzer.dp32 to x32/plugins directory
Copy xAnalyzer.dp64 to x64/plugins directory
Create a folder ...
6
votes
x64dbg (x32dbg) log registers every step like windbg
There is no such functionality in x64dbg out of the box, but we can make your own by writing a plugin! There are many examples (often with source code) available on http://plugins.x64dbg.com.
In this ...
- 1,652
5
votes
How to view string references?
The way is:
Debug -> Run to user code
Then you will see the strings of the program itself.
x64dbg/x32dbg as any other debugger, walks you trough all the process initialization code before ...
- 243
5
votes
Accepted
Automating bypassing anti-debug checks
What you could do:
With each found anti-debug, patch the exe with the bypass and continue with the patched one.
If your debugger is scriptable (like e.g. Ida) run it under the script, insert ...
- 1,964
5
votes
Storing a string with with x64dbg
I don't know how to do it in x64dbg, but here is another way to achieve it.
Open your ocx (dll) file in Resource Hacker and you should see the resorces within your dll file. Then click Create ...
- 3,369
5
votes
Accepted
xor eax,3 why does the input change the way it does?
In C, this function would look like this:
int fun()
{
int a;
// some code you haven't pasted here; probably scanf("%d", &a);...
if (some_condition)
a ^= 3; // xor a with 3
...
- 3,369
5
votes
Accepted
x64dbg or alternative: Run to selection while storing all ran opcodes
On Windows Travel Debugging (TTD) is a perfect use case for this scenario.
To use TTD, you need to run the debugger elevated. Install WinDbg Preview from Windows 10 store using an account that has ...
- 1,235
5
votes
Accepted
How to run a script in x64dbg
To launch a script, it has to be first loaded into x64dbg — you will see it in the Script tab:
Before loading a script, the content of this tab is empty:
...
- 1,120
4
votes
Accepted
How to copy binary file with x64dbg\x32dbg after it changed it self
It sounds like you want to dump the executable. You can use Scylla (which is built into x64dbg) to dump and restore the executable.
You can find Scylla in Plugins -> Scylla
- 1,652
4
votes
Accepted
Forcefully interpret code in x64dbg
You are encountering the issue of backwards disassembly. When you give x64dbg an address to disassemble at it will start decoding at exactly this address, go to the next instruction, etc.
For example ...
- 1,652
4
votes
x64dbg - see the current position?
From your screenshot I understand that you want to break on. You can do this by breaking on the debug string event. Use the following setting:
If you want to pause the execution, simply click the “...
- 1,652
4
votes
Comparison between orginal and modified DLL files with x64dbg
You shouldn't use a debugger to search for differences. You should use a diff tool. Of course, most diff tools work on ASCII text, but there are some that deal with binary files.
Some examples:
...
- 4,912
4
votes
OllyDbg vs x64dbg - Does OllyDbg have any particular advantage over x64dbg?
Outside of maybe custom plug-ins or perhaps buried features and usability differences, there's really no incentive to use OllyDbg over x32dbg/x64dbg. Since OllyDbg was the debugger of choice for so ...
- 2,234
4
votes
Accepted
How to save (trace) the execution route/sequences in debugger and Replay?
You may want to use "Trace record" and "Run trace".
Using Trace record, the debugger records and highlights every instructions as you step through the code. You will easily know when the same ...
- 6,040
4
votes
Go back to the function call address
You have two options, assuming the function is not inlined:
at the beginning of the function look at the stack, it should point to the caller. In some cases it can be possible to optimise the ...
- 233
4
votes
Accepted
What does ds mean?
The ds means "data segment" register in x86 architecture, while ss states for "stack segment" register. You would probably want to read link for more comprehensive description. When you see
mov ds:[...
- 3,369
4
votes
I am analyzing an exe with x64dbg but I dont see the address 00401000
no every exe will not start from 0x401000
the image base is hardcoded in header and is configurable with /entry switch when linking (ms linkers)
the operating system can and will override the ...
- 16.3k
4
votes
Accepted
bypass license of very old software, Access violation (C0000005) x32dbg
mov al, 1, the instruction you want to use becomes b0 01 (you can check here), assuming x86-32. That is, 2 Bytes.
The instruction you are patching (mov byte ptr ds:[ecx+0x72], al) is 88 41 72 and so ...
- 10.9k
4
votes
Accepted
Function Prologue, add esp directive
The large integer that is added to ESP is negative and is used to move the stack pointer to a an address that allows 0x44 bytes on the stack for the current function.
At this point, ESP=EBP-0x44. So, ...
- 882
Only top scored, non community-wiki answers of a minimum length are eligible