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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Good Binary Vulnerability Research Resources [closed]

I have spent the past several months refreshing my knowledge of x86 and updating to understand x64, and going through binary exploit development courses. Now that I am equipped with the necessary ...
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3answers
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Did somebody start to reverse engineer the proprietary Linux Brother Cups drivers?

I'm not very experienced with graphic or printer formats. My first (and only try yet) was to print a Tux.png with 265 x 314 pixel via the Chromium browser and see what Wireshark shows as USB transfer. ...
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4answers
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Converting assembly code to c

I have the following assembly code over Linux distro: # using the .data section for write permission # instead of .text section .section .data .globl _start _start: # displaying some characters ...
3
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0answers
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I want to know more about how a particular exploit works. How do I do that? [closed]

I am given a VM of a server running a vulnerable version of ProFTP and a attacker VM which exploits the server using an exploit provided with MetaSploit. I need to write a Snort rule to detect ...
4
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3answers
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RE Compressed backup file,router linux based so is it compresed with zlib?

so I have backup from my router its zte zxv10h201l and its linux based but I can not identify type of compression of this file. Here is couple of first "lines" of it 00000000 99 99 99 99 ...
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2answers
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IDA Pro converting to instruction functionality: how to automate.

I am loading various files that read into IDA as binary. Once I have the GUI in front of me I am able to go through the segments and hit "c" in order to convert to instruction/code. However, I am ...
4
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1answer
2k views

Merging elf shared-objects

Let say I have libA.so and libB.so, is there any way for me to combine them into a single shared library libC.so that contains all exported symbols of both libA.so and libB.so?
5
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3answers
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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, ...
11
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1answer
5k views

Understanding the most recent heap implementation under Linux

A few days ago, I was wondering how one could teach himself heap-based overflow exploitation. So I searched through documentation, subsequently practicing what I read in order to have a better ...
6
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1answer
1k views

Calling fgets while debugging under IDA Linux

I have _fgets call in a program I want to debug in IDA. My program receives SIGTTIN while calling it, that's normal. But when I mark to pass SIGTTIN to application, program waits for input in terminal,...
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3answers
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unpack Clear spot .bin firmware update

I am trying to unpack a clear spot firmware update The firmware I am trying to reverse can be found on the download page of the vendor I have used the fwtools to unpack the firmware as described on ...
4
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1answer
613 views

Changing parameter of function call in ELF executable

I want to alter a ELF executable function call and replace one of it's parameters. The executable calls dlopen() function and passes RTLD_NOW as the flag parameter. I want to change it to RTLD_LAZY. ...
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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 ...
21
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2answers
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How to reverse engineer simple usb device [windows -> linux]

I'd like to reverse engineer my usb beer-can refrigurator, which does connect via USB on windows and via simple GUI tray-tool can set/query temperature. I was thinking about running virtualboxed ...
8
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2answers
3k views

Attaching GDB to a specific fork

I am trying to reverse engineer a Linux binary that makes several fork() calls. I am using GDB 7.5 on Ubuntu. What I am trying to do with GDB is attach to a certain fork() (say the second call). Is ...
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3answers
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Why does the function pointer get overwritten even though is declared before the vulnerable buffer?

I am working on io-wargames for fun right now, level3: I do understand why there is a stack-overflow in this code (strlen(argv[1])), but what I don't understand is why it overflows the function ...
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2answers
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Why are GOT and PLT still present in Linux static stripped binaries?

I am looking at statically linked linux x86 stripped binary. I noticed that there are .got and .plt sections. I wonder what does a statically linked binary need got and plt sections for ? Anyone ?
11
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3answers
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Hooking functions in Linux and/or OSX?

I want to hook functions in a library (lib.so or lib.dylib) from another process. I know that unlike windows libraries, libraries in linux and mac still have their symbols (function names and ...
11
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1answer
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How are stripped shared libraries linked against?

Lately I've been reversing the Android framework for the Nexus S mobile phone. 99% of the source code is of course open, but there are few propriety shared libraries which needs to be downloaded in ...
72
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3answers
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How are the segment registers (fs, gs, cs, ss, ds, es) used in Linux?

I try to understand the process of memory segmentation for the i386 and amd64 architectures on Linux. It seems that this is heavily related to the segment registers %fs, %gs, %cs, %ss, %ds, %es. Can ...
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2answers
5k views

Base address of shared objects from ldd output

I'm on a Linux machine with ASLR disabled. Running ldd on a binary gives me the following result : linux-gate.so.1 => (0xb7fe1000) libc.so.6 => /lib/i386-linux-gnu/libc.so.6 (0xb7e5c000) /lib/...
102
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1answer
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How to handle stripped binaries with GDB? No source, no symbols and GDB only shows addresses?

I have GDB but the binary I want reverse engineer dynamically has no symbols, that is when I run the file utility it shows me stripped: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), ...
18
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3answers
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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 ...
12
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3answers
9k views

Locating Linux Kernel Symbols on ARM

Igor posted a great answer previously on SO about the format of the Linux kernel image on ARM. Assuming I can't boot my kernel image, can someone give me pointers on finding this compressed symbol ...
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0answers
311 views

Hauppauge HVR-950Q - Linux - Signal Processing for extra data like subtitles [closed]

I have a Hauppauge HVR-950Q running on a stripped down debian. I am trying to use the Hauppauge HVR-950Q from the command line to parse subtitles and build a library of accurate subtitles. I am not ...
3
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3answers
620 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 ...
6
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1answer
409 views

How can I check I've moved outside the stack without triggering a protection fault?

I'm adding a feature to my Linux debugger (I'm using Ptrace to manipulate the traced process as well as libbfd/libopcodes) to unwind the stack and determine if discrepancies exist between each CALL's ...
5
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3answers
983 views

Linux protectors: any good one out there?

I know no one that works as of today (i.e., kernels not way too old) and I wonder if anybody found or knows any protector for Linux either commercial, open source, used in malware, etc...
6
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2answers
280 views

How should I go about trying to figure out the programming language that was used?

I have an executable file and I would like to figure out which programming language was the source code written in. The first step would be to use a disassembler. What should be done after that ? ...
44
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8answers
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How do I add functionality to an existing binary executable?

I want to add some functionality to an existing binary file. The binary file was created using gcc. Do I need to decompile the binary first, even though I sufficiently understand the functioning of ...
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4answers
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How to check if an ELF file is UPX packed?

I have an ELF file and want to know if it is UPX packed. How can I detect UPX compression in GNU/Linux?
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1answer
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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 ...
33
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5answers
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How can I analyse an executable with no read permission?

I have a binary on a Linux (Kernel 2.6) which I can execute, but can't read (chmod 0711). Therefore no static analysis is possible. user1: $ ls -l bin -r-s--x--- user2 user1 bin user1: $ file bin ...

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