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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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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1answer
158 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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Examining Stack Frame in GDB

I am learning exploitation from the book "Hacking: The Art of Exploitation". In the program an integer variable auth_flag is declared after a char array password_buffer. So on stack frame first ...
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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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104 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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1answer
239 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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1answer
140 views

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
400 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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1answer
173 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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129 views

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
426 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
338 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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1answer
131 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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1answer
871 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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1answer
425 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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1answer
164 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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1answer
112 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
102 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
146 views

Help in the process arm disassembly

I have an ARM disassembly as follow, I would be happy if you can help me to understand what it does: ldr R14 ,=0X1234 ldr r10 , [r14 , #0x555] mov.w r15, #0x6666 add.w r10,r15,r10,lsl#15 I think ...
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2k 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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2answers
756 views

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
905 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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486 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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1answer
601 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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1answer
1k 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 ...
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113 views

Using the AND operator to find a heap allocation size, Fermin's formula

I came across this technique, leveraging the HPA feature (Heap Page Allocator, known as PageHeap) in gflags from Windows debugging tools, to find the size of a heap allocation: Lets say you have ...
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1answer
93 views

Is it possible to restart over a program by calling an entry point function?

I was wondering if it was possible to restart a program (ignoring previously mapped files) with different argument by either calling main() or a glibc entry point function.
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1answer
678 views

SWF flash analysis

An SWF file was recently detected by Windows Defender as SWF/Meadgive. I uploaded a sample to VT and only Microsoft flagged it as malicious. As of today's signatures I am not seeing any further ...
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1answer
131 views

Is stack migration a standard attack technique?

I am reading up a writeup on an example attack here where I have come across the technique called stack migration. The page is translated to English. Googling doesn't give me any fruitful pointer on ...
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1answer
592 views

Buffer overflow on server

I have a server (for reference: pastebin.com/ghJX69uH) that I can netcat to and it will ask to input a message. I know it is vulnerable to buffer overflow, but I can't seem to get the shellcode to ...
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1answer
2k views

Basic Buffer Overflow Help

I am currently practicing for a CTF competition and one of the practice challenges is a buffer overflow exploit. Before this challenge I knew absolutely nothing about these exploits, but I've been ...
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1answer
287 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
613 views

How should I approach a basic CTF exploitation challenge?

Complete newbie alert so apologies on what you're about to read. I've an executable I'm working with to achieve buffer overflow on. This is for an old CTF that has been and gone but I chose it to ...
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1answer
840 views

How to find the stack and other info in a memory dump? ARM

I'm reversing a closed platform to try gain execution using an exploit, a stack overflow. I've been told that (since there are no debuggers) the best way is to use RAM dumps (that I have) to try ...
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1answer
10k 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 ...
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1answer
342 views

How to find vulnerabilities in stripped binaries?

Do you just use tools like strace and a debugger to disassemble and find syscalls and then read the disassembly to find say for example a buffer overflow? Is that all you can do? I mean after all you ...
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1answer
1k views

Immunity Debugger - !mona suggest

I have been going through some tutorials for exploit development that use the !pvefindaddr command to help with creating unique patterns and discovering the offset. I know that mona has replaced ...
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2answers
828 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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1answer
780 views

VirtualProtect return value

VirtualProtect is straightforward but I get some results that I can't explain. Something's going on in the background probably but I'd like to know what. The following is under Windows 7 SP1 Ultimate ...
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1answer
330 views

Why is otkloadr.WRAssembly.1 reference present in a office file?

I was working with a RTF file and I found the string "otkloadr.WRAssembly.1" present inside the file in plain sight. I know that many exploits use this for loading the msvcr71.dll (non-ASLR module). ...
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4answers
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Not enough space for shellcode

I am working on an exploit for a ctf-challenge and could't find any hint about my problem. My steps so far: I could successfully overwrite EIP with an "jmp esp" address and jump to my shellcode. I ...
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1answer
782 views

Testing for bad characters in building an exploit doesn't seem to work as expected

I am trying to recreate the exploit linked here on Windows XP Professional SP2[x86]. I am building the exploit one step at a time. I have this snippet of code in Python3: f = open("crash.m3u", "wb") ...
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1answer
635 views

Stack smashing in X86_64 leads to Segmentation fault .

I been trying to smash the stack in an x86_64 machine , the payload gets executed when I use a debugger (gdb) and fails with Segmentation fault when I run it normally Here is the vulnerable program ...
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Lego NXT Exploitation and Vulnerabilities?

First, I wasn't sure if I should post this on the Lego Stack Exchange site or here, and I decided this site had more to do with the question (I hope I don't get bad rep for this). OK, my friends and I ...
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1answer
513 views

Where to start with iOS debugging?

Long story short, I have always had a jailbroken device, I have written and ported multiple tools to iOS, and have a fair knowledge of objective-C, ROP, and Linux exploitation. I have begun to take an ...
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Why can't I get the EIP to reflect my input

I am going through a tutorial which shows you how to exploit a stack based buffer overflow in a sample C program. The C code is: #include <string.h> void function(char *str) { char buffer[...