Questions tagged [linux]

A free and open source POSIX compatible operating system with a monolithic kernel and a kernel module system. Originally created by Linus Torvalds.

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604 views

ZyXEL P-2812HNU-F1, replacing the U-Boot on the board

I want flash regular(non branded) firmware on ZyXEL P-2812HNU-F1 router, which have branded version of firmware (customized for local MSO provider). To do this, I should first replace the U-Boot image ...
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582 views

Reverse Engineering Wifi Chip-set Firmware [closed]

I have Sparrow Wireless Adapter which from Qualcomm originally Wilocity that supports Wifi over 60 GHz (802.11ad or WiGiG). I have the firmware files of the wireless chipset (wil6210.fw and wil6210....
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1answer
3k views

Unable to view stack and memory addresses in IDA Pro [duplicate]

I am debugging a 32-bit ELF executable using remote GDB debugging option of IDA Pro. However, I am unable to view the contents of stack in the stack view. Also, the stack pointer value is: 0xFFFFD328 ...
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Why the extracted content differs?

I used binwalk to extract firmware.bin image, the extracted content is squashfs-root dir, and a separate dpc.squashfs file. Then I used sasquatch utility to extract content of dpc.squashfs file, and I ...
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Where can i find unix/linux tool for fuzzing for kill-switches? [closed]

I'm looking for linux/unix open-source tools for fuzzing ethernet card for kill-switch packets. https://en.wikipedia.org/wiki/Fuzzing I can imagine how it would be long to brute full of range on ...
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4answers
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Can IDA Pro on Linux disassemble a Windows PE (or Mac OS X app)?

I am thinking of buying IDA Pro for my Linux programming environment after reverse engineering a bit with OllyDBG (under WINE)... But before I endorse into such a costly purchase I ask the following ...
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1answer
7k views

Reverse engineering a golang binary file

I compiled docker by myself with some modifications. I would like to perform some static analysis to the binary. Mostly to see which parts of the code take more memory, etc. It's on linux (elf). Any ...
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3answers
4k views

Limited BusyBox shell

I'm testing some embedded device, and there is lack of documentation. When I telnet to device, I get only limited shell. BusyBox v1.19.2 (built-in shell (ash) Enter 'help' for a list of built-in ...
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2answers
2k views

How to know the arguments of a Linux syscall?

To my knowledge, this is a decent resource to know the parameters of a Linux syscall. However, this only lists 32 bit syscalls, not the 64 bit ones. Moreover, the reference doesn't say which register ...
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2answers
427 views

How to interpret disassembled MIPS code?

I have disassembled MIPS binary with raw opcodes. How to interpret, for example, these lines: Disassembly of section .data: 00000000 <.data>: ... ... f864: 30a5ffff sd ra,-23248(...
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2answers
2k views

Adding additional language to Linux based Firmware of Volkswagen Car Radio

I'm owning a CarPlay head unit from Volkswagen called RCD330 plus. It is possible to upgrade/downgrade to any available firmwares. For example here are two firmware versions: http://rcd330plus.com/rcd/...
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Recognize the library functions of statically linked executable file in IDA Pro

Recently I worked on a Linux program which has all of its symbols stripped. Opening it with IDA resulted in none of its functions identified. Thus I tried to extract any usable information from the ...
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1answer
70 views

Significance of link address 2000 8000 7C00;

Can you explain to me the significance of link address 2000 8000 7C00? It's in a MACRO from the GRUB configure script, which checks whether OBJCOPY works for absolute addresses. Here's the snippet ...
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1answer
1k views

Unpacking firmware

I have a ROM dump firmware which must be reversed (as a task). Binwalk output: DECIMAL HEXADECIMAL DESCRIPTION -------------------------------------------------------------------------------...
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1answer
33 views

What is causing \r\n in libnotify? [closed]

I am trying to look under the hood of libnotify, and ran strace notify-send 'hello' and one of the system calls is: sendto(5, "AUTH\r\n", 6, MSG_NOSIGNAL, NULL, 0) = 6 Surrounded by a: sendmsg(5, {...
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1answer
127 views

How do I go about overriding a function internally defined in a binary on Linux?

To be specific, I cannot recompile this binary, nor do I have access to the sourcecode. The functions are not defined within a shared library. So, how can I go about changing a function, or ...
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1answer
243 views

x64 Linux reverse-engineering - understanding asm code and inject eax

In a rootme exercise, i'm trying to bypass the control impleted to protect a "read" function. You'll find enclosed the code i'm refering to. As you may understand, i can inject data (with limitations) ...
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2answers
101 views

Unable to exploit format string vulenrability on Ubuntu 18.04.2 LTS

I am studying from "Hacking: The Art of Exploitation" and in program fmt_vuln.c format string is exploited. I am getting Segmentation Fault error. Checking position of AAAA on stack: $ ./fmt_vuln ...
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1answer
101 views

Understand what Ioctl do

I looking in ida on arm linux binary . I can see there that there is ioctl call ioctl(fd,req,num). fd is fd to /dev/module. ,req is some 4bytes and num is some number. How can I understand what ...
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1answer
134 views

Remote debugger for Linux from one VM (IDA) to another (running the debuggee)

I want to debug a Linux program (ELF), but my IDA Pro is on a Windows 10 VM and I want to use remote debugging to debug the program on Ubuntu (also in a VM). So, is it possible to debug if both ...
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1answer
79 views

Linux Assembly Syscall

I'm learning how to write shellcode by using Linux system call "execve" to spawn a shell with root access privilege. Here i found a shellcode online: http://shell-storm.org/shellcode/files/shellcode-...
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1answer
707 views

IDA remote linux Debugger attach to a running process

I usually use remote linux debugger as shown below: ./linux_server bin And in IDA Pro, I select Remote Linux Debugger as the debugger and set the process options accordingly with the IP address and ...
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1answer
577 views

Linux x64 Disassembly: single movzwl operand question

A quick question regarding a movzwl instruction which do not behave as I expected. here is the disassembled code: movzwl (%rax),%eax Before the instruction, rax is 0x7fffffffe410 and point to 0x5 ...
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1answer
299 views

My nopsled getting Segmentation fault (core dumped)

After overwrite the EIP register, I try breakpoint on the function strcpy() and then run the program after a breakpoint in the debugger. Then I check the ESP register : (gdb) i r esp esp ...
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1answer
82 views

How is linux loaded into a closed platform that has been hacked?

Today I have a question which may be a little uncertain. How would you "port" the Linux OS to a new platform? For example; The nintendo 3ds or the PS4, are consoles which have been recently "hacked", ...
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1answer
1k views

Extract YAFFS filesystem from binary

Iv got firmware from vivax set-top box backed up on flash drive and I vould like to change splash screen on it. The firmware seem to be yaffs but I cant extract files in order to change something. :~...
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58 views

Why does this execve shellcode work with this argv?

I wrote the following program in fasm, and am using Evan's Debugger on Ubuntu to debug it: format ELF64 executable 3 segment readable executable entry $ mov rbp, rsp sub rsp, 32 mov rax, 'this a t' ...
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0answers
25 views

Capturing traffic of an integrated laptop keyboard

I'm trying to capture the traffic between my laptop's integrated keyboard and its controlling software on Windows. I'll analyze the traffic to write a driver for Linux to control keyboard backlight. I ...
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45 views

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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27 views

Stack trace with GdbServer

When I debug binary file on linux with gdbServer with Ida ,I don't see stack trace. Why? How can I fix it to see stack trace??
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0answers
554 views

Executing MIPS binaries on Ubuntu Linux

I have a 32-bit MIPS binary and I'm trying to execute it on Ubuntu 64-bit. file command for the binary shows: bin: ELF 32-bit MSB executable, MIPS, MIPS32 rel2 version 1 (SYSV), dynamically linked (...
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1answer
130 views

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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0answers
59 views

What memory security settings are needed to allow a basic buffer overflow on Fedora 25?

I'm having a rather difficult time determining what memory security settings need to be adjusted on a fresh install of Fedora 25 in order to perform basic buffer overflows in the C language. As a ...
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1answer
109 views

Intel PIN and nm unable to capture binary symbols

I'm trying to generate a log of all identified symbols in a binary file. The application i'm trying to inspect is busybox. I've created a Pin Tool that successfully captures symbols (no demangling) ...
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0answers
71 views

dlmalloc free pointers

I was looking at the implementation of "free" in my current dlmalloc(both the source and the disassembly). However, I could not find the code section the inserts the FD and BK into free chunks. What ...
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1answer
129 views

Finding “free” inside libc.so

I extracted the libc.so.6 from within a vulnerable image used for exploitation purposes. I open up the shared object in IDA and I look at the symbols inside the "Exports" tab. I find "free"; upon ...
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355 views

Intercepting syscall in a shared object (dynamically linked)

Ditto. Any technique that allows to intercept sys calls issued from a shared object file? At runtime, the shared object is dlopen'ed by main(). One candidate is to use static binary rewriting (e.g. ...
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1answer
405 views

Monitoring Exceptions raised by an executable

Using tools like strace I can figure out the signals a program receives as it executes, regardless of whether or not signal handlers for those signals have been defined. [EDIT] In order to do the ...
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0answers
117 views

Set up an interrupt handler at kernel mode

I'm looking for something (a tool?) that can help me achieve my current goal: write a driver that can momentously interrupt the execution of the operating system (Linux, in my case), let me be able to ...
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2answers
695 views

Formatting output of objdump -sj .text filename.exe

I am hoping to get the contents of the .text section, of a Microsoft PE file using a linux command. When I use objdump -sj .text filename.exe the output consists of the offset, in hexadecimal ...
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1answer
286 views

Error: Invalid PE header machine value with pedump

I would like to dump the .text section on MS Windows .exe PE files in Ubuntu 14.04.4. I install pedump, on my Ubuntu system using sudo apt-get install mono-utils When I tried running pedump code /...
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1answer
5k views

How to decrypt data in binary file by XOR operator using a given key at specific offset? [closed]

I've a binary data files which are encrypted by a simple XOR cipher using a given key at offset +0x88 (which is 0x80 long), then the data (+0x108) is compressed by lzo1x. What would be the most ...
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1answer
601 views

Dynamic Analysis on ELF using IDA

On Linux, while generally reversing ELF files and dynamic analyzing (like step into, step over, break-point, inspecting registers value, memory etc) I use gdb or radare2 which provides dynamic ...
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1answer
296 views

Practicing what SHOULD be a simple crackme. Program calls strlen() but never returns

I'm trying out a crackme from the "LSE CTF" called "Blue Box" worth only 10 points. I've attempted this inside GDB and radare2... It is very simple, takes one argument and first checks to make sure ...
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0answers
518 views

Allwinner Camera Reversing: Compiling V4L [closed]

I've reverse engineered quite a bit of action cameras based on Allwinner's poorly documented chipset. It runs firmware closely related to H3, in fact I can compile a kernel that boots with no video ...
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2answers
324 views

Stopping at the original entry point in a packed file

During manual unpacking, the first task is to find to original entry point. The program jumps there after the unpacking is done. I took the bin/ls file, and checked with readelf -h that the entry ...
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2answers
141 views

Looking for reverse engneer online course [duplicate]

I looking for online reverse engeneer course. Course that study ida,reverse and patch for windows/ linux. Working with ida and another tool. I like many videos lesons. Do you know one?
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1answer
78 views

Which environment are comfortable for RE ( Free tool ) [closed]

I'm a beginner in RE. So i don't know which environments are better for me ( Linux or Window , 32bit or 64bit ). Which free tools are the best for each OS . Ollydbg is for Windows 32bit right?
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1answer
1k views

How can I turn .deb files back to .tar for reuse with other Linux distros? [closed]

We all know that Ubuntu is the most popular Linux distro today with plenty of application currently being developed for it. But then I use Fedora and some use other distros but still liked to have the ...