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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1answer
258 views

Help needed to extract u-boot kernel & rootfs - nxp lpc 3143 processor

I have a board where in principle aim at emulating a DVD-ROM loading iso file from a drive. This board is running a ARM CPU with 32MB of ram and has no vga output. The firmware update comes with 2 ...
2
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0answers
2k views

How to set-up GDB debugging in IDA Pro on Linux via Wine?

I tried running on linux via root terminal: gdbserver --multi localhost:23947 And then at IDA Pro at Wine I use Remote GDB debugger with my local ip and port: However when I start debugging I think ...
7
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2answers
5k views

ARM64 syscalls table

I wonder if there some syscall table for Linux ARM64 architecture? I found syscall table for Linux ARM32 and many other architectures, but the problem still exists. Does anyone know where can I find ...
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0answers
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??
3
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1answer
383 views

Lipo alternate for linux

Currently, I'm using lipo tool to extract the arch type from a fat iOS binary on a Mac OS. Now, I want to do the same on the linux platform for the iOS binaries, i.e. extract a given arch type from a ...
1
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0answers
89 views

Decrypt ibt.sfi linux firmware(Intel Wireless 8265 Linux Bluetooth)

Why I want to decrypt: Intel 8265 Bluetooth is likely a RAMUSB device, which needs system to update firmware. I try to transplant this linux firmware to macOS. Problems I met: The macOS BT firmware ...
0
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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, {...
1
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1answer
206 views

Fork and Waitpid calls in a CTF linux binary

I'm doing one of my first linux crackmes. In the first blocks of code, it goes inside some anti-debug routine and inside one of those it forks and after it calls a waitpid routine. I can verify it ...
6
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1answer
11k views

Managing inputs for payload injection?

I am looking for a complete list of the ways to inject a payload in a vulnerable program in a Unix (Linux) context depending on the inputs opened by the program. I know that there are several tricks ...
1
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1answer
2k views

How does this version of `rm -rf /` work?

On this website, I found the following code: char esp[] __attribute__ ((section(”.text”))) /* e.s.p release */ = “\xeb\x3e\x5b\x31\xc0\x50\x54\x5a\x83\xec\x64\x68\" “\xff\xff\xff\xff\x68\xdf\xd0\xdf\...
1
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1answer
302 views

why saved rip changed by push?

I am doing a reverse homework. see the following pictures: as can be seen from this picture, before call push touch3, "saved rip" is at 0x5561dca8, which is equal to the current rsp(0x5561dca8). ...
2
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0answers
2k views

OTOOL alternative for linux

I have a reverse engineering set up on a Mac machine. This set up does some reverse engineering on iOS applications(.ipa files). I'm migrating the setup from Mac to a linux machine. Currently on Mac, ...
0
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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 ...
2
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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, ...
0
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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 -------------------------------------------------------------------------------...
0
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1answer
136 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 ...
1
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1answer
62 views

Unknown parameters in custom signal handler on Linux

0x0000000008001946: mov 0xa8(%rdx),%rax 0x000000000800194d: lea 0x28(%rdx),%rsi 0x0000000008001951: lea 0x2(%rax),%rdi 0x0000000008001955: add $0xe,%rax 0x0000000008001959: ...
0
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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 ...
3
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2answers
197 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 ...
2
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0answers
2k views

Knockoff CGA/EGA to vga firmware update [closed]

The problem with this, as I know from experience in dealing with this exact same issue is the firmware in the CGA/EGA/VGA converter board. There is an update that needs to be written to the converter ...
3
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3answers
5k views

Use Android Shared library (.so) files in Linux

I decompiled an APK file,and that program have native codes in a .so file. I want to use that .so file in Linux in order to use inline functions. These codes have functions to connect to a server and ...
5
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1answer
430 views

How does API call work on Android (NDK)?

In windows platform, an application usually references its IAT(Import Access Table) to get the address of the APIs it wants, then call it. Then some mechanisms are done as demonstrated here nicely. ...
2
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2answers
314 views

Step Over not working in GDB

In the function below, let's say EIP is 0x400688. Now, I want to step over the call instead of stepping inside the subroutine. 0x40067a <main+4> sub $0x20,%rsp ...
2
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2answers
3k views

How can I change the value of a variable while debugging?

I know that I can output the value of a variable using (gdb) p var_name $1 = "varvalue" Is there a way to set the value of a variable while debugging with gdb? The document that I'm using doesn't ...
1
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1answer
139 views

Question regarding ASLR

If I have a binary file which does not have ASLR enabled. However, the libc file it uses has ASLR enabled, then will the address of system() in libc file be randomized every time? Or the address will ...
0
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1answer
80 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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0answers
566 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 (...
2
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1answer
2k views

What does fs and gs registers provide in Linux?

In a 64 bit ELF binary I found it mainly uses fs register to get some values. How can I know which value it wants to access? I'm familiar with that NT kernel uses fs and gs register for TEB structure ...
0
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1answer
716 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 ...
1
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0answers
456 views

Reverse Engineering Linux Core Dump

I have a Linux Core Dump file for a binary (which apparently crashed during execution) file command on the core dump: core.123: ELF 64-bit LSB core file x86-64, version 1 (SYSV), SVR4-style, from '/...
16
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1answer
3k 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 ...
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0answers
412 views

Passing input to program in Remote Debugging with IDA Pro

I am writing an exploit for a binary on Linux using IDA Pro. This binary, first accepts an input using getchar() and after few more code sections, it accepts a buffer as an input through stdin and it ...
18
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3answers
15k views

Detecting tracing in Linux

Under Linux it's possible to trace exactly the kernel system calls with strace. ltrace can be used also to trace library calls. I wonder if it's possible to detect if my executable is running under ...
1
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0answers
1k views

Unable to install ltrace on Kali [closed]

I am kind of stuck with the installation of ltrace on my Kali VM. My /etc/apt/sources.list file is updated with following entry: deb http://http.kali.org/kali kali-rolling main non-free contrib I ...
2
votes
1answer
516 views

Radare2 webui - need help setting it up

How can you set up Radare2 webui in Kali or Ubuntu or any other OS? I've tried so many different methods but none of them have worked so far. I think both of them are debian based so that might be ...
4
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3answers
3k views

Identify compression of this ZTE ZXV10 H201L V2 backup config file

This config.bin file is from a ZTE router. I would like to decompress it but I did not identify the compression used in the file. Maybe someone can. 00000000 99 99 99 99 44 44 44 44 55 55 55 55 aa ...
7
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2answers
15k views

How to reverse engineer a Linux executable to find the parameters? [closed]

So I am on a Linux box with an executable.Vague - I know. This is what happens when I try and run it with an argument/parameter: me@there:~$ ./theFile theOption -a ./theFile : option requires an ...
3
votes
3answers
584 views

What is “webcomp” and how does it work?

When reversing a router firmware based on DD-WRT I came across a mention of "webcomp". It seems it's used for storing internal HTML files for the web interface. What exactly it is and how can I ...
0
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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 ...
2
votes
1answer
51 views

Correct my understanding on a basic allocation memory

Here is the function If I understand correctly: There is a buffer of size 256 bytes created (malloc) in this buffer, the first 32 bits are set to 0 (because dword designates 32bits size) the next 32 ...
3
votes
2answers
622 views

How to dump a firmware from an old cell phone with Linux?

I have a "MiracleBox" software for GSM repairing and and old cell phone (Wiko Lubi 4) with a RD8851CL chip inside. With this MiracleBox running on Windows I can make a dump of this chip without ...
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1answer
604 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 ...
2
votes
1answer
909 views

extract zImage from MS-DOS executable

I have an aarch64 kernel image with the following magic number: root@localhost:/# cat msImage|xxd -l4 00000000: 4d5a 0091 MZ.. root@localhost:/# file msImage ...
0
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2answers
434 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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0answers
157 views

Immunity error BB010002

I am trying to make this exploit work and having some difficulty. So I skipped to a 'fixed' version of it from here and the only thing I changed was the shell code: https://github.com/cokebottle/oscp-...
2
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0answers
370 views

Obscure router refuses to flash OpenWrt

This is a very obscure Chinese router from a brand called Wavlink. It's the Model: WN529R2/WN529R2P. It's web interface was pretty limited and wouldn't allow firmware modifications. I found GND/Tx/Rx/...
4
votes
1answer
1k views

Radare2 debugging - How to get into lazy imported functions?

I have a linux binary that imports functions from an external library (shared object). The functions are lazy loaded and not available when rip is at @main or @entry. When i step into such a function (...
3
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0answers
87 views

methods for identifying deliberately unmagiked filesystem

I am trying to restore a system from backups around some obnoxious copy protection. It is a Linux system from an vendor that does not appear to comply with the GPL and has overwritten the header of ...
3
votes
2answers
1k views

Flashing firmware on an embedded device

Anyone want to help out a noob? (excuse my incorrect terminology/ knowledge) I am venturing into unknown territory. The only experience I have is rooting/flashing firmware on my phone and installing ...
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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?