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
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Why are symbols with local binding present in the symbol table of my ELF files?

I found out that there are symbols with binding=LOCAL and visibility=HIDDEN in the symbol table (.symtab) of ELF executables/libraries. What are they needed for? They are not involved in the ...
2
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1answer
3k views

How to decrypt the config.bin from ZTE ZXV10 H201L

I have this file from my router its backup of user config,I suppose its compresed with zlib and encrypted with AES. Utility which is resposible to compress it and encrypt it is called cspd. In side ...
5
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3answers
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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
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4answers
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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 ...
1
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1answer
147 views

3 questions on Assembly - meaning of code, Decompilation in Linux, Higher level perspective,

Following the question here (3 questions on assembly - syntax, meaning, and equivalent in high level code (eg C++)), I would like to know for the same x86 code in AT&T syntax: xor $0x20, (%eax) ...
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3answers
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How to extract content of NVRAM file?

How to extract content from NVRAM file? NVRAM type is SPI Serial NOR Flash. NVRAM has been copied as mtdblock partition. An embedded device that run Linux v2.6.18_pro500. Linux version 2.6.18_pro500 ...
2
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1answer
596 views

How to store files on a router's NAND without writing the whole firmware

I want to modify my ZyXEL P-2812HNU-F1 dsl router by storing some extra files in /etc. However, /etc is mounted as tmpfs so changes are lost on reboot. But there's probably a way around it ;) # cat /...
0
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1answer
338 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 ...
3
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1answer
3k views

Can't get buffer to overflow over function pointer

I cannot get this buffer overflow exploit to work for the life of me. The source code is here. It is from the book, Hacking the Art of Exploitation. The subject here is the below struct: struct user {...
0
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0answers
65 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 ...
2
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1answer
627 views

Writing own custome syscall/int 0x80 on x64 system

Is there a way to write my own syscall/int 0x80 without using them? So, normally it goes like setup registers ... syscall or int 0x80 and I am interested in doing this without syscall/int 0x80 ...
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0answers
377 views

Using __kernel_vsyscall on x64 linux machine [closed]

I am trying to use __kernel_vsyscall instead of syscall/int 80 on linux x64. I have read that it can be done on Intel chips (I have one), but i can't find how can one do it. I have x32 version: int ...
9
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2answers
21k 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 ...
4
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2answers
2k 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 ...
0
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1answer
88 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", ...
12
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1answer
23k 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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0answers
663 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....
3
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1answer
2k views

Help mounting jffs2 dumped from NAND flash.

Ok so have been trying to look some settings from a jffs2 partition I extracted from a nand dump I had done previously Here ----> https://forum.openwrt.org/viewtopic.php?id=67564 Steps I have ...
0
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1answer
120 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) ...
2
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0answers
1k views

open a non-standard compression .tar.lzma file extracted from firmware download

We are trying to examine a firmware download for a product we have running on our local network. Using the command binwalk -Me filename we generated a folder that contains the following content: ...
3
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2answers
2k views

Technicolor TG799vac Modem/Router Dumping The Nand Flash

Ok, so I have been trying to dump the contents of a Technicolor TG799vac. So far I have removed the flash chip and read out the chip using the DumpFlash.py utility and used binwalk to locate the ...
1
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3answers
929 views

Is it possible copy and save bootloader using CLI telnet commands?

I need get copy of original Bootloader from device running embedded Linux. Is it possible copy and save bootloader using CLI telnet commands? I have full access to CLI interface. Is there way copy ...
2
votes
2answers
933 views

Finding a place to inject shellcode

I am following the tutorial for ROP Primer, level0. The tutorial sets the memory at the beginning of [vdso] writeable and executable and copies the shellcode there. I do not know why, but it seems ...
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0answers
601 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 ...
1
vote
1answer
316 views

Is it possible to rebuild an nexe file if I can read at arbitrary untrusted memory addresses?

Ok, I’m in a remote situation where I don’t have access to the remote filesystem but where I can run arbitrary python code (except I can’t fork processes and I don’t have access to ulimit and uname). ...
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2answers
3k views

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 ...
0
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3answers
6k 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 ...
2
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0answers
121 views

Trace replayer won't load binary debug information

So I'm debugging a linux application with what I believe DWARF debug information on x86-64 host. Everything is working fine and as expected - the source files are loaded immediately on function ...
2
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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
2k 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. :~...
2
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0answers
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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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1answer
278 views

Master of Orion and scanmem

I am looking to use scanmem to change in game credits in the new Master of Orion (2016). Steps I have taken: Install and run scanmem as root Track credits successfully using scanmem It ...
5
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3answers
7k views

Segmentation fault while pushing onto the stack

So I have been following some tutorials on assembly and the instructor compiles the following code: ;hello3.asm attempts to make the code position independent section .text global _start _start: ;...
5
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3answers
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QEMU & router firmware

I'm trying to get the router firmware (binary) running on QEMU (if that is possible). All networking is set up fine because I've tested it using the debian_wheezy_mips_standard.qcow2 sudo qemu-...
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2answers
1k 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 ...
-1
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1answer
384 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 /...
7
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2answers
2k views

32-bit binary stack layout on a x64 Linux OS

Stack layout is well documented in many ways. Especially for x86 systems as there were numerous tutorials on how to exploit stack overflow on old 32-bit systems many years ago. So far we can know ...
1
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1answer
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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 ...
1
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1answer
342 views

What checksum algorithm is this network protocol using?

I've been working my way through an undocumented TCP-based protocol by monitoring traffic with tcpdump, Wireshark, and some Python packages (scapy, numpy) with good luck so far, but I've hit a wall ...
2
votes
2answers
3k views

Static analysis of Windows executable from a Linux platform

I am trying to do some static analysis on crackmes written for Windows on a Linux platform. I am using radare2. My problem is that most of the time I am unable to find the "real" code, for example the ...
6
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3answers
3k views

Debugging forked child in an anti-debug protected crackme

I am interested in the anti-debugging method implemented in the crackme called trace-p. A child process is forked, which communicates with the parent using int3 instructions. I would like to debug the ...
11
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3answers
16k views

ZTE encrypted backup config file

I was poking around in ZTE Speedport Entry 2i (CPE used mostly in Germany, Slovakia etc, probably custom made for Deutsche Telekom). It's possible to download backup of config from UI. I found out ...
6
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3answers
2k views

Reversing self-modifying code

I am learning reversing an I am studying a code, which modifies itself (actually it is a crackme). It contains statements like: movw $0xc031, 0x(%edx), where edx contains the address of a statement. ...
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2answers
486 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 ...
6
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0answers
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How to unpack manually an upx packed elf file

I am trying to learn to manually unpack an upx packed elf file. The examples I have found are for Windows, mostly with Ollydbg, and as I see the first step is to look for pushad and popad instructions....
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1answer
83 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?
4
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0answers
321 views

Modern equivalent to rsymtab for reconstructing symbol table for statically linked / stripped binaries?

I'm working with a 32-bit ELF binary that (I believe) has been statically linked against a few different third-party libraries. It has also been stripped, so I don't have much to go on with respect to ...
1
vote
1answer
1k views

Memory segment in IDA - ARM kernel

I just loaded up an ARM kernel image into IDA. When I boot up the ARM kernel and inspect the kernel symbols, I can see the following :- / $ cat /proc/kallsyms | head -n 10 00000000 t __vectors_start ...
3
votes
1answer
994 views

using GDB and dealing with breakpoint detection

I am trying to solve a reverse engineering challenge using using gdb. I can run the program inside it but when I set a breakpoint at main then I get Program received signal SIGSEGV, Segmentation ...
4
votes
2answers
5k views

Reversing Hisense TV Firmware

I am looking for methods to get root on my Linux smart tv. Anyone have any ideas, in order to try extract the kernel config. Hisense is no help when asking for GPL source. I ran metasploit against it ...