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Questions tagged [debugging]

Process of analyzing live programs through software (e.g. ptrace) or hardware (e.g. JTAGs) devices.

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6answers
27k views

Decompiling a 1990 DOS application

I have some crucial data written decades ago by an ancient 16bit DOS application. There are no docs, no source, and no information about the author. Just the 16 bit exe. I guess it's time for me to ...
17
votes
3answers
21k views

Cross debugging for ARM / MIPS ELF with QEMU/toolchain

as i'm new about cross-debugging and cross-compilation i need some help because i feel so confused. I have a MIPS elf file, [myelf][1] .You can see bellow the output of file myelf: myelf: ELF 32-bit ...
17
votes
4answers
4k views

How to reverse engineer a Windows 10 UWP app?

I wanted to see what Microsoft are doing when you click "Restart now" button in their Settings -> Update window on Windows 10: Somehow the results are not the same what is available via ...
14
votes
1answer
2k views

Debugging with radare2 using two terminals

I have been trying to figure this out for quite some time now, and would really need some help. Firstly, some intro: I am running the newest version of radare2 from Github on a 64bit Ubuntu 16.04 and ...
13
votes
2answers
10k views

Set a breakpoint on GDB entry point for stripped PIE binaries without disabling ASLR

Given a position-independent, statically-linked, stripped binary, there does not appear to be a way in GDB to set a breakpoint at the entry point without disabling ASLR. break start and similar ...
13
votes
3answers
535 views

Trying to understand this construct in Dbgv.sys driver for DbgView tool

I'm trying to reverse the Dbgv.sys (x86 kernel driver) for the DbgView tool. It has this sub_10D4A function that is called almost at the beginning of the driver's DriverEntry function. It goes as such:...
12
votes
2answers
2k views

How can I find the source of a string in an old DOS game?

I am attempting to amend some strings in an old DOS game (FIFA International Soccer), specifically the names of players. In the past it hasn't been too hard to pull off such a task on post-DOS games ...
12
votes
2answers
11k views

How to find arrays of objects (entities, enemies) in a game I'm reversing with Cheat Engine?

I am reversing a game using Cheat Engine and OllyDBG, through this memory addresses within an FPS game are read and monitored, these addresses will contain the coordinates(xyz) of enemies. My ...
10
votes
1answer
714 views

Static analysis data combined with dynamic analysis knowledge

What I'm doing now is placing an awful lot of comments about function variable values, global variable values as comments in my IDA database, which I find ugly after a while and obviously not a best ...
9
votes
3answers
7k views

Jump back to the caller

I'm debugging some app inside the ollydbg, so this two steps i set to start debugging the app. I load the exe from file menu with input arguments Set breakpoint on msvcr71.printf function After this ...
8
votes
1answer
2k views

How to investigate Windows 32/64bit (WOW64) transition

There is surprisingly little information about Windows WOW64 mechanism. I'm trying to investigate it. So when we have system call in 32-land, it calls an address that is stored in FS, which leads us ...
8
votes
1answer
9k views

How to debug DLL imported from an application?

I want to debug a DLL when it is called from an application. For example, when Firefox calls nss3.dll "NSS Builtin Trusted Root CAs" to check HTTPS Certificates, I want to catch the nss3.dll and debug ...
8
votes
2answers
710 views

Open-source equivalent for FLIRT

I am using a C disassembler and I need to identify compiler-intrinsic functions (i.e. SEH_prolog, SEH_epilog etc.) within my C program. Right now, the only way I can do that is to use IDA's FLIRT (...
8
votes
2answers
264 views

Lego NXT Exploitation and Vulnerabilities?

First, I wasn't sure if I should post this on the Lego Stack Exchange site or here, and I decided this site had more to do with the question (I hope I don't get bad rep for this). OK, my friends and I ...
8
votes
0answers
1k views

GDB via JTAG on ARM Hardware target without source code

Does anyone have other solutions for connecting to a remote ARM target without IDA? This is the question and below I give examples of setup's i have tried, should anyone be interested. Update: ...
7
votes
1answer
19k views

How to debug the DLL of an EXE using IDA Pro?

I'm fairly new to the RE world, started right around a week and have gotten my hands dirty with some really good stuff on this website. Pardon my naive knowledge. Currently, I'm trying to reverse a ...
7
votes
2answers
473 views

Trace assisted code identification?

I'm working on an RE project and had an idea for a tool that would help me greatly and wanted to see if it already exists. I'd like to find a specific part of code in the binary. Searching for ...
7
votes
2answers
321 views

Reverse engineering Windows Defender's signature for Metasploit Framework's metsrv.dll

As a pentester for a consulting agency, it is part of our job to "evade" antivirus after gaining code execution on information systems. It is indeed necessary to prove exploitation of vulnerabilities, ...
7
votes
2answers
3k views

How to deal with Static Memory Allocation while modifying an executable?

I'm not new to StackExchange, but I'm quite new to reverse engineering, so please be patient with me! :P At present I'm dealing with an executable that I would like to modify a little bit, for ...
7
votes
2answers
2k views

“Debugged application has modified the debugging registers” with ollydbg 2.01

I have the following problem. When I open a sample with ollydbg v2.01, then I get that message here: Debugged application has modified the debugging registers. Maybe it called ZwContinue() or ...
7
votes
1answer
4k views

Problem while debugging with gdbserver in IDA Pro

I'm new to debugging with IDA Pro and I ran into the problem that my breakpoint is not hit while attempting to debug with gdbserver. The program is written by myself and it is simple to debug with gdb....
7
votes
1answer
617 views

Can I evaluate operand values of an instruction currently at breakpoint (while debugging) in IDA using IDAPython?

Let's say I have lots of breakpoints at some push instructions. I am trying to dereference the operand (if address) - get the actual relevant value for each one in a script, handling immediate, base + ...
6
votes
3answers
2k views

Is there any tool to visually see program stack in linux while debugging?

By stack I mean the location where local variable, return address etc are stored. Which is pointed to by the esp and ebp.
6
votes
2answers
4k views

Break on returning to a specific module

I'm debugging an application in OllyDbg, I pause the program at a specific place. Now I am deep inside ntdll and other gui related module calls, judging from the stack. I'ld like to break as soon as ...
6
votes
3answers
4k views

windows kernel debugging on Mac host (using VMware fusion)

in windows host we can use WinDBG and serial port communication for connection to windows kernel and the most easiest way is using VirtualKD. now the question is, is there any possibility of doing ...
6
votes
1answer
145 views

ARM debugging interesting behavior

I was just disassembling and debugging an ARM binary for fun and I noticed something unusual. Consider the following set of instructions:- 0x00008058 <+4>: mov r1, pc 0x0000805c <+8>...
6
votes
1answer
5k views

What is the difference between step into and step over when debugging?

I am using EDB and stepping through the program but I do not even know what the difference in behavior is when doing this. I feel like this is something I should know if I ever have hope of reverse ...
6
votes
1answer
1k views

Handling INT 2D anti-debugger technique in IDA Pro

I'm analyzing a PE file using IDA Pro that is using int 2Dh technique as anti debugging: CODE:00455050 push ebp CODE:00455051 mov ebp, esp CODE:00455053 push ecx CODE:00455054 push ebx ...
6
votes
1answer
1k views

Calling fgets while debugging under IDA Linux

I have _fgets call in a program I want to debug in IDA. My program receives SIGTTIN while calling it, that's normal. But when I mark to pass SIGTTIN to application, program waits for input in terminal,...
6
votes
3answers
8k views

x64dbg how to debug a DLL called from an application

I have a 64 bit application that when runs will load a dll (plugin) I want to debug only this plugin, I have tried setting x64dbg to break on dll load, but two issues, this app loads hundreds of other ...
6
votes
1answer
866 views

How to know which module am I currently in? (EIP/RIP pointer)

I'm currently learning IDA Pro, that is set up with the WinDbg debugger. So, say, I triggered a breakpoint and began stepping in and out of functions. I prefer to work in the "Graph view" mode: What ...
6
votes
1answer
1k views

OllyDbg: How to set a conditional breakpoint for a value anywhere in the stack?

I know how to set conditional breakpoints on a register, but how can I have a breakpoint trigger if a specific value (say, 0x12345678) appears anywhere in the active call stack frame?
5
votes
3answers
708 views

Any documentation available for r2 other than official book

I am interested in learning and using radare2 as a toolset for reverse engineering. But I want ANY other resource for learning this tools other than radare2 book, preferably a video series. What I am ...
5
votes
2answers
1k views

How do I approach this CTF Debugging Program?

I have an ELF executable I'm working on (got it from a previous CTF competition). The executable simply asks for a password, and then it prints out "congrats". The code snippets and my annotations ...
5
votes
2answers
13k views

Remote debugging with IDA and GDB

Recently I've run across an ELF file that I would like to debug using IDA. I've used GDB for basic debugging but I would like to utilize IDA. I've been researching for a while and can't seem to find ...
5
votes
1answer
2k views

DOS program debug in IDA?

Does anybody know something hack to debug 16bit DOS program in IDA 6.1?
5
votes
3answers
452 views

Changing a windows name by patching create window function call

I use x64dbg and IDA Pro the process is 32bit. I'm not sure if I'm doing this right or not because I'm getting a crash which I'm not sure if it's caused by me doing something wrong or the startup ...
5
votes
1answer
6k views

How can I set breakpoint and get value of a register with IDApython

How can I set a breakpoint and get the value of the EAX register with IDApython? I want to set a breakpoint, for example at address 00b27223, and at each break before execution of that specific ...
5
votes
1answer
748 views

Are Reverse Debuggers Impossible on OSX?

I have been impressed with the reverse debugging (that is stepping back in time through a program) capabilities in GDB and tools like QIRA, but I am a little confused as to why no such program exists ...
5
votes
1answer
1k views

Using a VMM/hypervisor to monitor guest OS execution?

I would like to set up a virtual machine monitor using Microsoft Hyper-V, VMware vSphere/ESX, Xen, or any other alternative hypervisor solution that is able to monitor the execution of a guest OS (a ...
4
votes
3answers
1k views

Faster Kernel debugging for Windows

I am Kernel debugging in Windbg and it's slow , very slow stepping through. My current setup is using VMWARE and Windbg through a com port on the Virtual Machine. Is there a faster way to debug the ...
4
votes
3answers
2k views

How to break on not-yet-loaded kernel driver

I've been reversing a sample of the Uroborus trojan for my own learning joy. I'm having a hard time following it once it loads a windows kernel driver that implements the rootkit. I've set up my ...
4
votes
3answers
2k views

Does IDA support remote debugging in their Freeware Version?

I am unable to find if it does. This PDF linked here says that from version 4.8 IDA Pro supports remote debugging. But I can't seem to find this in the UI for the Freeware Version 5.0. Or is it that ...
4
votes
2answers
3k views

How to break when specific text is found

In this line of code: mov eax,dword ptr [eax+8]; eax+8 contains a long string of text, I want to find out where it originally came from. In either OllyDbg or x32dbg, how can I break when ...
4
votes
3answers
7k views

Kernel debugging - how to set breakpoint at DriverEntry?

I'm sorry for my bad English. I'm a beginner in Reverse Engineering. I have a problem like this. I was given two files, one is driver's .inf file and the other is driver's .sys file. My mission is to ...
4
votes
1answer
7k views

When to use OllyDgb over Immunity Debugger

I have always been curious when I should use OllyDbg over Immunity Debugger. Immunity Debugger has inherited code from OllyDbg and can perform scripted debugging with Python. Interestingly enough, ...
4
votes
1answer
588 views

Finding execution flow/calls to functions?

I have a binary and I'm interested in an high level overview of how it operates. I was trying to generate a list of functions called during a particular execution, with their hierarchy, for example ...
4
votes
1answer
871 views

Why did the program entry point become 'sub esp, 1C'?

I compiled the following C++ code with MinGW and opened it in OllyDbg 2.01. And the program stops at the following lines: CPU Disasm Address Hex dump Command ...
4
votes
1answer
91 views

registers set by function

How can I figure out which general-purpose registers are modified by a function call. I am programming a Win32 Assembly program that calls IsDebuggerPresent(). According to MSDN, it will return a ...
4
votes
1answer
272 views

Is there a way to explicitly connect r2pipe to an existing radare2 session that I have open?

I understand that I can execute my script within a session using [0x401000]> . server.py and the pipe will be connected to it when I call r2pipe.open() with no arguments. Ideally I would like to ...