Questions tagged [stack]

Part of a process memory that stores all the automatic variables and the call-stack of the functions currently called by the process.

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Ghidra Decompiler Optimized Strings

Looking at a large x86 binary, I'm seeing lots of instances where strings are assembled on the stack as quadwords like so: If I try to set the type of puStack40 to char[38], I get the following ...
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37 views

Where do mouse/keyboard GUI inputs get queued or stored?

Where do mouse-clicks in a program's GUI window/menus (Windows OS) get stored in memory? Is there some sort of input/GUI "queue" similar to Windows messages queuing? I'm wondering if it'd be possible ...
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Why does this x64 stack have other bytes and seems to be in reverse order?

I wrote the following small C program and you can also see the stack in the screenshot. My question is twofold: How come there are entire rows of other data between the 3 stack strings? Why is my ...
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exploiting a binary using ret2libc

I ran into this binary at a CTF : https://github.com/auehc/AUCTF-2020/tree/master/Pwn/House%20of%20Madness I first tried to exploit it and get a shell using ret2libc technique, however I didn't ...
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Extra Allocated Space in Stack and Wrong placement of Local Variable

I was recently reading reverse engineering for beginners by Yurichev where I happened to come across an example x64 MSVC and x64 GCC code. In this I'm unable to understand why there is a shadow space ...
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What is the “Thread XXXX Stack” Section in x64dbg memory map?

So I am trying to understand how an Aegis Packed Malware works, and from what I am seeing the executable is passing the control to a section labelled Thread 2380 Stack after the EntryPoint. This ...
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61 views

x86 main preamble makes stack aligned on 32-bytes boundaries

For the record, I've read all stackexchange relevant answers on the topic (here and here) plus other articles to fully grasp the concepts of memory alignment and CPU natural boundaries. But for some ...
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How large are privileges of linux kernel module?

I know that kernel modules are practically part of the kernel since it gets loaded inside it. But I am not sure if it really gets all privileges the system has. Can it read/write code inside the ...
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Why EIP is being overwritten before local buffer ends?

I am doing a simple buffer overflow exercise, here is the source: //vuln.c #include <stdio.h> #include <string.h> int main(int argc, char* argv[]) { char buf[256]; strcpy(buf,...
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Bufferoverflow Stack

I want to do a buffer overflow exploit in the stack. For this i read in data via the "gets"-function. void ExploitMe() { char buffer[256]; gets(buffer); } I compile this file with gcc test.c -...
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244 views

ELF x86 - Why is return address pushed twice?

I reverse an ELF x86, and I would like to understand why the return address is pushed again on the stack? It should be already present there. main: lea ecx, [esp+0x4 {argc}] and esp, 0xfffffff0 ...
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Find out if address store in heap or stack

While dynamic debugging with ida and gdb-server on binary file running on linux , I saw address that store some value. How can I know if this address allocated in stack or in heap?
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radare2 shows main function arguments argv as pointer to char on the stack, not as pointer to pointer to char

Well, I've been digging around process command line arguments as well as environment variables a bit these last days, especially looking up the way main function arguments were pushed onto the stack. ...
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253 views

How to examine/edit stack memory contents using radare2 in debug mode?

How can i examine/edit stack contents using radare2, just like gdb ? Is there a way to examine memory using $rbp or $rsp register like below. x $rbp-10 <--- something like this which can dump from ...
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4k views

How to print the value of register with Radare 2

I am trying to solve this ELF - Ptrace challenge. I use Radare 2. This is the commands I execute to print the assembly code. radare2 ch3.bin [0x080482f0]> aaa [[anal.jmptbl] Missing cjmp bb in ...
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What is a good resource to learn about how the call stack works while programming in C?

Sorry if this is a duplicate and please point me in the right direction if so. I have a strong foundation in C programming and I know how memory is allocated on the stack for variables/arrays/...
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755 views

Why stack canary can be brute-force one byte at a time?

I am reading brute-forcing stack canary. But I am confused why the server can be brute-forced one byte at a time on a crashable-server and what does mean this fork-and-accept ?
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How to identify if buffer allocate on stack or heap?

When I looking on Ida with static analyze I see that buffer pass to function/ function fill data in buffer. How can I know if this buffer allocate in stack/ heap?
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668 views

Why dont use memcpy? [closed]

Why using memcpy can cause to stack overFlow? memcpy get the number of bytes to copy, so what is the problem , and how memcpy_s fix it?
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Changing local variable in caller from callee in C?

I'm implementing a function which is going to perform some time-consuming task, and I'd like to hack the benchmarking part a bit by changing the variable indicating the CPU time my function has ...
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208 views

Remote Debugging Linux Binaries - Stack Address Changes?

Do stack addresses change every time we remotely debug a Linux binary using linux_server and IDA Pro? I am using IDA Pro and remote debug a linux binary which is running on a Linux machine and I am ...
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677 views

How to execute a specific shellcode with a non executable stack without using format string? (without ASLR and stack cookie)

First off we don't have ASLR and stack cookie, and assume we can't create our own files on this system So I'm trying to execute a shellcode in this code, this is what i have done so far: i have ...
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530 views

Is the value of EBP before the main function important?

So before we come to the main function, it looks we are in a function with a name __libc_start_main and before we come to our main function we obviously push EBP value in the stack ( the value of EBP ...
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I have control to EIP but no have idea when put the shellcode - not have any dll return adress

for the practice i take some C code and compiled i try put shellcode open some calc and i not have idea which method i need to use #include <stdio.h> #include <string.h> int main(void) {...
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Why code subtracts 60 from esp when the length of the variable is 64

I was following a tutorial that introduced stack overflows. Here is the c Code. #include <stdlib.h> #include <unistd.h> #include <stdio.h> int main(int argc, char **argv) { ...
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What is the difference between xrefs and stack trace?

In IDA, I can see what calls a specific function by looking at the xrefs to it, or by looking 1 step back on stack trace. What are the differences between them? How does IDA know what the stack ...
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249 views

Why doesn't this retn instruction return from the function?

I disassembled an exe file on Windows with IDA and saw this function prologue: I see that when the retn executes instead of returning it jumps to sub_1314cba4. Why doesn't the retn instruction ...
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Understanding Program Arguments on the Stack in Assembly

To self-teach myself reverse engineering, I am writing small C programs and reversing them in order to understands how the compiler sees my code. However, I am having quite tough time understanding ...
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179 views

how to calculate max possible stack size utilization

Is there any elegant way to calculate the maximum possible stack depth utilization of a program, using IDAPython? currently my best approach is iterating through all functions and counting stack-...
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more memory allocated on the stack than seems to be needed [duplicate]

Im working on the bof challange in http://pwnable.kr/play.php. the source code has a function func: void func(int key){ char overflowme[32]; printf("overflow me : "); gets(overflowme); // ...
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299 views

Which ARM command is influencing the SP position?

I do static analysis of ARM assembly code (I can't debug it). When I look on argument that in SP+0x<SomeOffset> I can find what I'm looking for, but if I look a few lines further down I see ...
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168 views

Basic hello world stack manipulation troubles

I'm a beginner in reverse engineering, and as a beginner I started to read "Reverse Engineering for beginers". Here is the hello world program from the book (taken from chapter 3, page 12) : Now ...
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323 views

Backtracing where a register gets initialized

I am currently trying to bypass a CRC check, that exists inline on many places in an application to check if memory pages in the .text section have been modified. Short explanation of the crc32 ...
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152 views

How is data transferred from the process’ memory to the console screen?

I am learning about how the call stack works by reverse engineering binaries using Radare2 (in a Linux environment). The ISA on the server (a P5 micro-architecture) I am analyzing binaries off of is ...
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255 views

IDA makes an incorrect guess about how a virtual function affects the stack. How can I correct/override it?

So this may be a weird question. I'm working with a windows 32-bit executable in IDA that was originally programmed in C/C++ (Mostly likely with Visual Studio .NET 2002). For the virtual function ...
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1answer
112 views

ARM system crashes after changing stack address

-- Edit with latest update on the problem, it is not solved yet :( -- While playing with an ARM embedded Linux system (Version 3.8.13), out of curiosity, I created a small "debug" kernel module. ...
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Can we see local variable directly by inspecting the disk image (file in disk)?

As far as I know, global and static variables are stored in heap memory, while local variables are on stack memory. I think this is the case when we speak about a binary file (like PE) that is located ...
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885 views

My core dump's backtrace stops to a signal handler, what can I do?

I obtained an ELF core dump that was provoked by fuzzing a proprietary server. As I do not have access anymore to the machine that hosted this server, and the server is part of a tightly coupled set ...
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359 views

Fixing '__asm' in pseudocode in IDA PRO (inconsistent fpu stack error)

So I was doing some REing in IDA, changed a function parameter type and suddenly my stack pointer messes up (1025B361: inconsistent fpu stack). Does anyone know what to look for here or how to fix it? ...
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787 views

Understanding the output of Windbg's `dds esp`

I am not sure if I am understanding the raw output of dds esp or its 64-bit counterpart dqs rsp properly. When I see a list of entries in the stack, I tend to assume that wherever I see return ...
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What could be the purpose of XORing esp with a global variable? (stack canary protection)

I am currently looking at a function inside a Win32 executable's main module. After allocating memory on the stack (sub esp) and saving some registers on the stack, the value of esp is XORed with a ...
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ESP out of range of “Stack View” in IDA

A very similar (or exact) question was asked here, though it was not answered properly. I am debugging a process in IDA and am unable to view the dynamic contents of the stack because its value ...
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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.
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What additional data does a compiler populate the buffer space with? [duplicate]

I am currently learning about the stack, in particular how to perform stack overflow attacks. I understand that the buffer is not the size that the program initially set it as, for example if we ...
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Two arguments pushed on stack, callee only shows one argument

I have found myself confused while reversing some programs (specifically the IOLI Crackme challenges). I have no trouble solving them, but I have come across something that I do not understand and it ...
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133 views

whats the purpose of this code snippet?

I'm using at&t ordering I came across this a little while ago and while i understand why we want to push a stack frame when we call a new routine I don't see why it was done here: (for the ...
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136 views

Is stack migration a standard attack technique?

I am reading up a writeup on an example attack here where I have come across the technique called stack migration. The page is translated to English. Googling doesn't give me any fruitful pointer on ...
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How can I control local variable ordering on stack in gcc?

I am writing a reversing challenge where I need to seed a bug. It's important to have a particular ordering of local variable on stack in a method. However, gcc seems to shuffle those around. How can ...
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950 views

How to find the stack and other info in a memory dump? ARM

I'm reversing a closed platform to try gain execution using an exploit, a stack overflow. I've been told that (since there are no debuggers) the best way is to use RAM dumps (that I have) to try ...
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Passing argument through registers instead of the stack

I'm learning (and re-learning) C and assembly, and I came across a difference between what I've been taught and the actual result I have. Some code: int test(int a, int b){ return a + b; } int ...