Questions tagged [exploit]

Using techniques to change the behavior of an application or application component in order to use it to ones advantage. When used it is often referred to software exploitation where an attacker can take control of an applications execution flow in order to run arbitrary code.

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Question About Buffer Overflow And NOP Sled

I am trying to learn buffer overflow but I have a question about one CTF. In "Buffer Overflows" CTF in Tryhackme, while creating the payload, I can use '0x7fffffffe388' or '0x7fffffffe398' ...
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What is data only exploitation?

I was wondering, and after trying to read for the past several months I got totally lost and don't understand this concept. Could someone please explain in simple words the concept of data only ...
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There is a course in which they teach you to use WinAFL?

I would like to know if there is a course that begins in a basic way, such as how to use winAFL to find bugs in app desktop.
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How to find bugs in a modern desktop application with reverse enginnering?

I would like to clarify the context for the question: I have studied different types of exploiting but all the studies I have carried out were with command line programs and with functions that I ...
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43 views

Linux allocator and heap exploitation

I have some internal questions regarding linux allocator and heap exploitation: Is there a technique/techniques to discover the type of the memory allocator in linux(for example: dlmalloc/ptmalloc/...
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Thread keeps generating page fault

So i was recently trying to exploit a kernel mode driver (HEVD) and I encountered a problem which doesn't make sense to me. After i jumped to my shellcode (which resides in usermode), the thread keeps ...
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Fuzzing Third Party Windows Drivers

I want to contribute to vendors while learning how to be a security researcher, and I was wondering: How can I fuzz third party windows drivers? (For instance, those that come with cpu/gpu and similar ...
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324 views

Advanced Binary Exploitation CTF

I wanted to ask your assistance: Where can I find advanced ctfs (that hopefully contain solutions) regarding binary/kernel exploitation? I am interested on finding x86_64 linux/windows/arm64 that ...
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215 views

Bypassing ASLR without leak address

I have found a stack buffer overflow. Currently this is the situation: NX/DEP disabled ASLR enabled Not a PIE I am able to override the return address and jump to PLT sections. My problem is that I ...
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259 views

Finding Ropper/ROPgadget offsets in Ghidra disassembly

How is the offsets returned from ROP gadget finders related to the files they come from? For example, if the ROP gadget finder says that a certain gadget is at offset 0x0002ae74 in libuClibc.0.9.3.so ...
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112 views

How the return address of the notesearch program was calculated in "The Art Of Exploitation"

I am reading the book "The Are Of Exploitation" 2nd Edition by Jon Erikson and there is something I don't understand about the calculation of the return address. In page 137 it covers the ...
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I found an arbitrary free, (free(<abitrary address>)), managed to locate a candidate address I wish to free, how do I proceed from here?

While doing my first code auditing as a novice vulnerability resarchers I managed to stumble upon my first free() in my target. I managed to find a candiate location where I can control this value and ...
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838 views

Buffer overflow: pwntools does not give me a shell, despite exploit working without pwntools

Recently, I've been trying to learn how to use the pwntools library. I am trying to exploit the following program using pwntools: #include <stdio.h> #include <stdlib.h> int main(void) { ...
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system doesn't invoke /bin/sh

I am learning libc shellcode attacks and trying to execute /bin/sh from system I can execute other commands from system like whoami and ls -a but can not run /bin/sh the following works string = b&...
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xIP vs xSP vs xBP: How to choose the target?

We have 32bit & 64bit binaries, and in ROP (Return Oriented Programming), we sometimes target RSP/ESP, sometimes RIP/EIP, (maybe) sometimes RBP/EBP (I'm new to this, haven't seen RBP used yet). In ...
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1k views

What do these 2 Ghidra warnings mean?

When disassembling ARM binaries in Ghidra, I often see these warnings: /* WARNING: Could not recover jumptable at 0x0747c198. Too many branches */ /* WARNING: Treating ...
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Newbie problems exploiting a format string vulnerability

I encountered a print format vulnerability challenge in a CTF. I don't know anything about these vulnerabilities, so I'm working my way through Saif El-Sherei's format string exploitation tutorial ...
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1answer
118 views

Format String Direct Parameter Behavior

I am investigating a format string vulnerability on arm64 (linked against musl libc), and am encountering some odd behavior while debugging the output. From the decompilation, the program has a ...
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184 views

Shellcode execution segfault

I have been trying to exploit simple buffer overflow caused by scanf. I'm working on x86 Linux. The point is to spawn a shell. I sucesfully overwritten return address and jumped into my shellcode. But ...
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exploiting a binary using ret2libc

I ran into this binary at a CTF : https://github.com/auehc/AUCTF-2020/tree/master/Pwn/House%20of%20Madness I first tried to exploit it and get a shell using ret2libc technique, however I didn't ...
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How to “unprotect” malicious workbook without knowing password

Right now I'm looking at an office document (most likely rtf based on it exploiting equation editor) that opens just fine when you double click it, but on further examination in a hex editor and in ...
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269 views

The buffer is too short to insert addresses when exploiting buffer overflow

Newbie here. Sorry for what you about to read . I'm currently working on exploiting a binary on Ubuntu 18.04. Here is some information about the binary: Its checksec information using pwntools: ...
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248 views

Abusing the strlen output

My question is related to the strlen function from the C and C++. I am reversing a program, that reads a byte data from allocated memory and sends to the strlen directly. To be completely honest ...
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1answer
385 views

Get NonPagedPool (NPP) Base Address on any Windows OS

Is there a way to get the the base(start) address of the NonPagedPool in Windows ? I know that it's dynamic for Post windows 7 Operating Systems (Does this include Windows server 2008 ?)
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305 views

Decompiler attack

I noticed that Hex-Ray have been keeping reward to people who find "security vulnerabilities" of IDA-Pro.: So here is my question, how come a decompiler can have "security vulnerabilities"? And more ...
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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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7k views

Receiving "Got EOF while reading in interactive" after properly executing system("/bin/sh") using pwntools

I've followed some tutorials on writing a pwntools-based exploit for the bitterman ELF binary, used in a CTF competition. However, all my attempts fail with the message below, i.e. Got EOF while ...
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300 views

gdb - searching for pointers to a given memory region

Let's suppose there is a memory region that is m'mapped in memory, we need to find its address (which randomly changes, because of ASLR) by following a pointer path, basically, I'm trying to find a ...
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1k views

Explanation of heap shaping technique and how it is different from heap spraying

Recent RDP vulnerability and exploits have mentioned the use of heap shaping technique. Can anyone please explain in details what is actually involved in using this tactic. Thanks
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Cannot rewrite the rip even after disabling all the security features

I was trying to exploit a simple buffer overflow on a self created binary. i have disabled all the security features by compiling with the flags - --fno-stack-protector -z execstack -no-pie. my ...
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Defence against cracking [closed]

Say I wrote an application and published demo version of it with a possibility to buy a full version. I was wondering if it is possible to stop people from cracking it, so that the only ones who use ...
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1answer
3k views

GDB: Could not load shared library symbols

I'm currently having a look at the Damn Vulnerable Router Firmware, and I'm roughly following the description that is given here: https://p16.praetorian.com/blog/getting-started-with-damn-vulnerable-...
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369 views

Returning to usermode shellcode from windows kernel (Win10)

I have written a kernel exploit (for the latest Win10 64bit) that executes (or returns to from the kernel) token stealing shellcode, which is placed in the VirtulAlloc'ed memory in the userland. The ...
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Need help understanding basic buffer overflow

So I have this sample problem that I need to buffer overflow. Its an elf file that require to be run on a separate terminal then using "nc localhost 'port' " on a separate terminal we can see the ...
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1answer
1k views

Why stack canary can be brute-force one byte at a time?

I am reading brute-forcing stack canary. But I am confused why the server can be brute-forced one byte at a time on a crashable-server and what does mean this fork-and-accept ?
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1answer
714 views

How to reverse engineer a Black Box?

I am trying to reverse engineer / research a black box system, this is, a system for which there is no public information at all. Let's say the system is a modern handheld console. I have already ...
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232 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 ...
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1k views

Extract firmware images from COTS embedded devices

I am on the hook to collect some of legacy firmware images from real-world embedded devices. Before digging into it, I am trying to confirm some high-level points. Is it in general possible to ...
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844 views

Heap Chunk Structure Does Not Contain Previous Section Info

I'm reading Shellcoder's Handbook to learn more about exploitation and overflows. I reached the chapter on Heap Overflows. The book mentions that a heap is split into chunks where each chunk contains ...
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Challenges to learn jemalloc exploitation on FreeBSD [closed]

I'm studying this phrack article: http://www.phrack.org/issues/68/10.html Very interesting but the only valid way to be confident with an exploitation technique is an hands-on. I'm searching for ...
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222 views

My Shellcode is in a non-executable part of a Windows executable. Is there still a way to execute it?

I'm trying to exploit a test server executable that holds some user-controlled data in memory. I can gain control of EIP and go there, however I get an access violation in OllyDBG because it's not ...
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207 views

Shellcode issue

I'm currently trying to understand a peculiar behaviour with a shellcode. When reaching a MOV instruction just before an interrupt the shellcode get modified: As you can see on the radare2 output, my ...
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1answer
107 views

Automatically find intput required to trigger a specific code path in a program

Assuming I have the following scenario: I have spotted a vulnerability in a specific function deep inside of an executable (DLL). To get that code path executed (in a vulnerable context) I need to ...
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1answer
4k views

How to exploit an suid root application

I have to exploit an application and I have only the 32-bit ELF excecutable, which is also stripped. Its a suid root application and when it is executed practically run the ls -al command for a ...
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Knowledge about CPU hardware

Recently, I have taken the computer organization course that explains in the logic gate level how a CPU works and etc... Up until now I have been treating the CPU as a black box that runs assembly ...
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Working Linux assembly XOR Encoder/Decoder Failing on Windows

Should I be able to extract shellcode from a basic (tested and working) Win7-64 message box app and place the extracted shellcode into a tested and working assembly language encoder/decoder and expect ...
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1answer
1k views

Why shell code only with nop slide working for me?

I'm trying to understand the exploit for SLMail 5.5. Here is the basic flow : I'm able to control EIP and point to an instruction "JMP ESP" ESP is pointing to the exact start position of my ...
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680 views

I have a question about SEH Overwrite

I am trying SEH Overwrite for vulnerable test programs. However, overwriting the RET and SEH chains through 41414141 (input value) does not cause the EIP to run as 41414141. The picture is that the ...
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972 views

Why always get the message "Illegal Instruction (core dumped)"?

I tried to exploiting buffer overflow. In the exploit code I use the Aleph-One shellcode. "\xeb\x1f\x5e\x89\x76\x08\x31\xc0\x88\x46\x07\x89\x46\x0c\xb0\x0b" "\x89\xf3\x8d\x4e\x08\x8d\x56\x0c\xcd\x80\...
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2k views

explain the vulnerable code used by EternalBlue SMB attack

The recent WannaCry ransomware attack exploited a vulnerability in older Windows SMB code. The presumably reverse-engineered function that has been cited 1 as vulnerable is as follows: unsigned int ...