Questions tagged [elf]

the Executable and Linkable Format is the main executable and object format for Linux, Solaris, *BSD, and many other OSes...

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votes
1answer
68 views

What is actually loaded here and different hexdump outputs on util-linux hexdump and on cutter and ghidra's hexdump

I was trying to understand what segment of file gets loaded by fourth LOAD header on phdr array. First 6 headers are shown below from readelf Program Headers: Type Offset ...
21
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4answers
27k 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 ...
14
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3answers
7k views

How to generate the call graph of a binary file?

I have a non-stripped ELF binary for which I want to create a call graph as a dot file. Is there such a tool which generates the call graph? EDIT: Is there away in addition to the conventional call ...
5
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2answers
6k views

Fixing corrupt ELF header field “e_shnum” for use in GDB

If the ELF header which usually can be read using readelf has been manually manipulated, let's say by increasing the value for the "Size of section headers" the binary still can be executed and works ...
6
votes
2answers
101 views

Reassembling ELF binary files

I have been doing a number of CTF activities when I came across something I’m unfamiliar with. As I am somewhat new to exploitation and reverse engineering, this was unfamiliar to me. I have 7 pieces ...
0
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1answer
38 views

problem rewriting ELF binary to add an additional loadable segment

I have a problem rewriting ELF binary to add an additional loadable segment for add.c code. I have problem working with https://pdfhost.io/v/U@uP1+nCY_Compact_Control_Flow_Integerity_in_Linuxpdf.pdf ...
0
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1answer
242 views

Disassembling Hexagon - Corrupted ELF

I downloaded and unpacked the modem from Google source, after that I used laginimaineb's script to unify all modem binary data. However, when loading this binary to IDA, I get an error says: "Binary ...
2
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1answer
411 views

Radare2 create section

Radare2 has S* commands, that can show, delete, modify sections. Is it possible to create new section in executable file and save it?
2
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1answer
63 views

Importance of learning file structures for reverse engineering?

I'm new to reverse engineering and I have started to study the anatomy of specific file formats, specifically PE right now. I really enjoy learning the different parts of the files and the different ...
2
votes
2answers
2k views

How to locate module_init() offset from ELF header of Linux kernel module?

The header is self explanatory but to explain myself better. I have an ELF binary - loadable kernel module, compiled with symbols. I want to know how to locate the offset of the module_init() function....
0
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1answer
57 views

Convert PIE ELF binary into No-PIE

Is it possible changing few bytes for converting an elf binary from PIE to No-PIE (ELF)? I know that in the header if e_type is: - 3 then the program is PIE - 2 then the program is No-PIE So I ...
3
votes
2answers
432 views

How can I get the byte size of an operand in IDA Pro?

I am trying to get the byte size of all operands in a given instruction from IDA Pro. At first I tried using GetOperandValue(ea,n) to see how large the value was and calculate how many bytes were ...
1
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1answer
214 views

Unknown Game Client Data

As asking a friend and no amount of Googling yielded an answer, I figured I'd make an account and give this place a go. I'm working on reverse engineering the server for a relatively old game with no ...
4
votes
2answers
207 views

Struct reconstruction in decompilers

I'm testing several decompilers about struct reconstruction, given the following C example: struct S { int x; int y; long z; long t; }; int foo(struct S s) { return s.x + s.y + s....
5
votes
1answer
808 views

Find function in a stripped dynamic ELF library

Im currently reverse engineering an android app and this app calls a function named "getUserInfo" in an ARM 32bit ELF library called "libcms.so" (from TikTok) via the Java Native Interface. My ...
3
votes
1answer
41 views

ELF file format find shared object for symbol

(in Windows) PE file format contains Import table with Module\Dll Name which tells PE loader where to search for symbol e.g. KERNEL32.dll -> CreateFileW In the ELF file format there is Symbol ...
1
vote
1answer
42 views

How to use x64-86 elf file from an apk file in a linux machine?

I'm building a jar file that use jni to load an x86-64 elf extracted from Android apk file. But when I run my app, it throw this exception: Caused by: java.lang.UnsatisfiedLinkError: /lib/x86_64-...
1
vote
1answer
72 views

Why is IDA showing three arguments for the main function instead of two in some linux binaries?

So I am reversing an ELF‌ binary, now from my knowledge in C the main function has two argument, argc and argv but some linux binaries that i am reversing have 3 when i decompile them! one int and ...
2
votes
1answer
44 views

IAT vs GOT address resolving: which of them resolve during runtime and which during load time by default?

So based on my knowledge on windows apps, as far as i know the IAT gets filled with correct addresses when the library gets loaded (correct me if I'm wrong) now in linux, they use GOT, and again ...
0
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1answer
46 views

How to determine when/where pointers in .ctors get mapped?

So I am learning about ELF, and am looking through a binary in Ghidra as I do. I've made sense of the ELF header, and now I am looking through the program header table. My binary has a bunch of ...
2
votes
1answer
635 views

Is there a way to debug an elf file that runs with no problems with damaged header?

My question is general, but to have an example to work with, let us take one from Whirlwind Tutorial. ; tiny.asm BITS 32 org 0x00010000 db 0x7F, "ELF" ; ...
4
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2answers
541 views

Edit an ELF file (language pack)

I have here an ELF file that contains a language pack (Englisch and Chinese) and I want to swap the chinese language to the german language. hex cannot represent Chinese :) here an excerpt from the ...
3
votes
1answer
6k views

Making changes in ELF file after dissassembly [duplicate]

I am new to reverse engineering and after some research, I haven't found a clear way to do what I want to do. I have an ELF file, but not the original source code that generated it. It is really ...
3
votes
1answer
103 views

Enumerating (name, addresses) in PLT of an ELF file without elf.h

I want to show users imported symbols of a given ELF file like this(#1) in a disassembler project.(Android app) 1d21a: f7fa e8e8 blx 173ec ; __android_log_print@plt ... Currently, I can only show ...
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2answers
155 views

Elf x86_64 adding function

I'm trying to see if I can append function code in the .text section of an ELF while still maintaining the execution flow of the original ELF. Ideally, I want to call the new function but that's it's ...
4
votes
3answers
4k views

How to SUCCESSFULLY add a code section to an executable file in Linux?

I am in Linux, and I have seen this question a few times but never, nobody answered how to really make this work. I need to add a section to an already compiled binary. Lets say for a moment is an ...
5
votes
3answers
6k views

Packers/Protectors for Linux

I was wondering if anyone had come across a packer/protector which could be used for ELF binaries. There seem to be quite a few articles on writing packers and protectors for the PE format -- however, ...
3
votes
2answers
6k views

Find base address and memory size of program debugged in gdb

I want to find out the base address and the imagesize of the program being debugged in gdb. As in, where it got loaded in memory. For shared libraries I can do "info sharedlibrary" and I get very ...
4
votes
1answer
95 views

How to find the index of static ilbrary functions in the PLT of the binary?

So right now I'm trying to resolve function calls and their names in my reversing tool the problem I'm having is that library functions such as printf and fwrite and such do not have a corresponding ...
1
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1answer
101 views

Why have two symbols tables?

Why have two symbol tables if .symtab already contains everything that's in .dynsym ?
2
votes
1answer
219 views

Position-independent code dectection

Is it possible to detect whether a given executable is a PIC by looking at the disassembler's output? If not, what are other valid ways to go about this?
1
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1answer
273 views

Changing entry-point of and ELF file

I'm trying to conduct a little experiment which basically consists of changing the EP of an ELF file and executing an exit(9) syscall, without returning to the OEP. As shown in the image everything ...
2
votes
1answer
139 views

Meaning of Flags in ELF Section header?

Given this classic helloworld.c example, #include <stdio.h> int main() { printf("Hello world!\n"); } In below sections output, the value for Flags presents a couple of different values, e....
2
votes
1answer
104 views

LD_BIND_NOW doesn’t seem to take effect on ELF PIE executable?

Observations When the Linux executable is compiled as PIE (Position Independent Executable, default on Ubuntu 18.04), the symbols from shared libraries (e.g. libc) will be resolved when the program ...
3
votes
1answer
192 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 ...
-1
votes
1answer
344 views

How reverse a stripped binary (Find the main function)

I'm learning the reverse, and I'm trying to reverse a stripped binary (flag: ELF 64-bit LSB executable, x86-64, version 1 (GNU/Linux), statically linked, stripped). I manage to go to the entry address ...
5
votes
2answers
3k views

IDA Load Symbols From Static Library

I have a stripped elf file that has statically linked libraries. Is there a way that I could take the original library files that are in a files and name the functions in IDA that match those in the ...
1
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0answers
720 views

Reversing ELF 64-bit LSB pie executable [duplicate]

I have a file crackme, which is an executable. hamuto@hamuto-pc:~/Security/NOOB/FruitSalad$ file crackme crackme: ELF 64-bit LSB pie executable, x86-64, version 1 (SYSV), dynamically linked, ...
1
vote
1answer
216 views

How to find the starting address of main function when the binary is stripped and _start doesn't push the absolute address value of main?

So let's say the ELF binary is stripped - meaning no symbol table - and the _start function doesn't push the address of main before calling __libc_start_main. This happened in a binary when compiled ...
2
votes
3answers
146 views

Is the main function's name in the symbol table of C & C++ programs always 'main'? if not, how to find the name?

So I'm trying to write a reversing tool that parses symbol table to find the main function's address right now all the binaries I'm checking the name of main function is still main in symbol table ...
1
vote
1answer
914 views

How do tools like objdump find names of functions and their start address in ELF binaries?

I have written a ELF parser that disassmbles the .text section using capstone my problem is that i dont know how can i segment the text section based on functions and print the name of the function ...
1
vote
1answer
797 views

ptrace TRACE_PEEKER: Input/output error accessing virtual address contents when traced file is a shared object file

I'm using updated Kali and compiling this for 64- bit Working through Learning Linux Binary Analysis,'simple ptrace-based debugger' on page 57. Source code and testfile to debug included. Problem ...
2
votes
0answers
50 views

Any way to edit an ELF binary without hex? [duplicate]

So, this is a noob question, I am a complete beginner in this field, so sorry if I'm wasting your time in any way. I wanted to know, if there is a way to edit an ELF binary without using a hex editor....
2
votes
0answers
2k views

How to export a working elf binary from Ghidra?

When patching a program and then using the export binary function, it turns the elf headers are corrupt. Is there any way to work around this problem?
-2
votes
1answer
37 views

DT_DEBUG not filled on dlopen [closed]

A target library "lib42.so" has DT_DEBUG entry in the .dynamic section. After dlopen("lib42.so", RTLD_LOCAL | RTLD_NOW) succeded, r_debug->d_un.d_ptr is equal to zero. Why?
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0answers
209 views

Find functions names in .init_array section in unstripped library

Is it possible to find out all instances of static initialization in a elf dynamic library. I can dump the array of function pointers in .init_array section via objdump command like this. objdump -s -...
0
votes
0answers
289 views

Finding function call (with arguments) in ELF file

I have two kinds of ELF files, built from C++. .so files: ELF 64-bit LSB shared object, x86-64, version 1 (GNU/Linux), dynamically linked, BuildID[sha1]=5e751e769912aef28bc63b888e5e4904b867a180, ...
88
votes
2answers
66k views

What is PLT/GOT?

From time to time, when disassembling x86 binaries, I stumble on reference to PLT and GOT, especially when calling procedures from a dynamic library. For example, when running a program in gdb: (gdb)...
1
vote
0answers
140 views

Need help understanding basic buffer overflow

So I have this sample problem that I need to buffer overflow. Its an elf file that require to be run on a separate terminal then using "nc localhost 'port' " on a separate terminal we can see the ...
2
votes
1answer
79 views

Process Immediately Killed

I'm trying to reverse an ARM executable. It's for an embedded system, but I don't have any details about the normally targeted environment. Here's what file shows: ELF 32-bit LSB executable, ARM, ...