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2
votes
1answer
58 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 ...
3
votes
1answer
183 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 ...
3
votes
2answers
416 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 ...
1
vote
2answers
1k views

Can't find the password anywhere in the binary

This is my first post here. I was recently involved in a capture the flag preparation test which involved decompiling an ELF 32-bit LSB executable, Intel 80386 file for Linux compiled with GCC. The ...
1
vote
1answer
698 views

Radare2 - Insert asm instructions without overwriting

In order to patch a x86 elf file on Linux, I'm struggling to insert a specific assembler instruction into the binary file without overwriting any of the preexisting instructions. I've been reading ...
0
votes
1answer
375 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
votes
1answer
1k views

Disassemblers resolving (ELF) section names

I'm working with linux executables and was just wondering how it is that section names are resolved to addresses upon disassembly of an ELF. For example take some random disassembly output from ...
0
votes
1answer
467 views

ARM ELF Obfuscation [closed]

Metamorphic is a technique to obfuscate a binary and change the opcode sequence and create new samples with same functionality. In my case, I have some elf binary of ARM processor type and their ...
6
votes
1answer
1k views

Understanding gdb output

So I was messing with gdb and came across something rather interesting. I ran the following code into gdb: int i, g = 1; for (i = 0; i < 100; i++) g++; Before execution, disas main ...
1
vote
1answer
2k views

Disassembling MIPS 32 version 1 binary with the Radare2 Framework

I am trying to disassemble a MIPS 32 version 1 binary with the Radare2 framework. Here is the full output of the file command: ELF 32-bit LSB executable, MIPS, MIPS32 version 1 (SYSV), dynamically ...
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 ...
2
votes
1answer
1k views

Finding hidden string location using radare2 on ELF binaries

I'm working through some reverse engineering sample programs (IOLI crackmes) crackme0x00 - crackme0x09 which are gcc compiled ELF format binaries. I was provided these by a colleague and can be ...
2
votes
2answers
2k views

how to locate linux kernel module module_init(function), function offset from ELF header?

The header is self explanatory but to explain my self better. I have an ELF binary - loadable kernel module, compiled with symbols. I want to know how to locate the offset of the init function. Can i ...
4
votes
1answer
977 views

Illegal entry point of an ELF file

I have encountered a quite obscure 32-bit ELF file (that is a crackme) and I still cannot figure out how can it execute. First, beside some "understandable" property that it has not any section: # ...
4
votes
1answer
2k views

ELF: How to make IDA show me the correct PLT (Procedure Linkage Table) content?

I would like to make IDA disassemble the .plt section of ELF files correctly, e.g. as objdump does: objdump -D -M intel asdf | grep "Disassembly of section .plt" -A80 I don't know why but IDA gives ...
4
votes
1answer
4k views

How to disassemble/run mips ELF file ? (with readelf error)

So i want to disassemble and then run a MIPS elf file for the first time. As i don't have MIPS hardware i am using mipsel-unknown-linux-gnu toolchain.Here comes the problem. The output of the command ...
1
vote
1answer
173 views

Reuse symbols in disassembling/reassembling a C++ program

it's me again. I am working on a tool can that disassemble/reassemble stripped binaries and now I am sucked in a (external) symbol reuse issue. The test is on 32-bit Linux x86 platform. Suppose I ...
7
votes
2answers
3k views

How to recover information stored in .ctors section?

Test is on x86, 32-bit Linux. I am using g++ 4.6.3 and objdump 2.22 Here is a simple C++ code I am working on: #include <iostream> using namespace std; main() { cout << "Hello ...
4
votes
4answers
1k views

Is it possible to (heuristic) identify the begin addr of main function in a stripped ELF?

So basically I am working on some tripped dynamic linked ELF binaries (32 bit Linux x86), using objdump to disassemble them, modifying and trying to reassemble them. In the unstripped binary, we can ...
3
votes
1answer
465 views

How to reuse symbol/data defined in .bss section?

So basically I am trying to re-use some assembly code/data dumped by objdump from 32 bit ELF binary on Linux. So basically, in the disassembled binary, I found some symbol referring to .bss section ...
3
votes
1answer
278 views

How to deal with this “error” instructions generated by objdump?

So basically I am using objdump to disassemble a binary from GNU Coreutils, on 32-bit Linux x86. In the disassembled code, I found one "broken" instruction like this: 804b4db: ff 24 85 e4 09 ...
10
votes
2answers
7k views

Why I can not directly get the content of `.bss` section?

Test is on Linux 32bit. I use this command to get the context of .text .rodata and .data section: objdump -s -j .text elf_binary objdump -s -j .rodata elf_binary objdump -s -j .data elf_binary But ...
3
votes
1answer
3k views

Why ther are some many padding/leading nop instructions in my binary code?

The test platform is on Linux 32bit, x86. So basically I wrote a simple C program like this: void main() { double a = 10.0; printf("hello world %f\n", a); } I use gcc to compile to ...