A buffer overflow, or buffer overrun, is an anomaly where a program, while writing data to a buffer, overruns the buffer's boundary and overwrites adjacent memory.

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3 byte address of system call and exit call

i am trying to exploit a buffer overflow vulnerability in ubuntu (kernel version 3.0.0-12 generic i686) by using the method return to libc and the stack is not exploiting ? By while exploiting i ...
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Execute form environmental variable while stack is not executable

Strange thing happened. I created EGG=NOPs + shellcode. Then i get the address of EGG; I made buffer overflow and jumped to it and get the shell(address of shell is the second parametr). How is this ...
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How to gain root privilege after injecting code using a buffer overflow vulnerability?

Once the attacker finds an exploitable vulnerability in a user program, e.g., buffer overflow. Assume his goal is to gain root privilege and typical countermeasures are not present in the system (ASLR,...
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Explaining a buffer overflow vulnerability in C

Given this C program: #include <stdio.h> #include <string.h> int main(int argc, char **argv) { char buf[1024]; strcpy(buf, argv[1]); } Built with: gcc -m32 -z execstack prog.c -o ...
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buffer overflow in python script

I am developing a script to perform an a buffer overflow for an assignment in school. However, I am stuck at a point where my payload works injected through the commandline, but not injected through ...
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How stack smashing is prevented?

I just read AlephOne's paper on smashing the stack, and implemented it on my machine (Ubuntu 12.04), it was a bit old so had to take a lot of help from the internet but I enjoyed it. Now, I want to ...
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648 views

Are buffer overflows on websites stoppable?

Recently, I was at the bookstore checking out books on computers. I found an interesting book on various types of hacks and how to stop them on your servers. One that caught my eye was the "buffer ...
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How is printf() in C/C++ a Buffer overflow vulnerability?

According to an article I just read, the functions printf and strcpy are considered security vulnerabilities due to Buffer overflows. I understand how strcpy is vulnerable, but could someone possibly ...
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Stack Overflow on ARM : Null Bytes Issue

I am trying to follow the research paper by Tiger Security for ARM Exploitation : Link For the simple stack overflow exploitation, the code is : #include <stdio.h> #include <string.h> #...
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Exploiting buffer overflow leads to segfault

I am trying to exploit simple stack overflow vulnerability. I have a basic code in c: #include <cstring> int main( int argc, char** argv ) { char buffer[500]; strcpy(buffer, ...
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Buffer overflow without using environment variables [closed]

I was trying to overflow buffers and I was wondering , Is there anyway to do a buffer overflows without using environment variables ?
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Bypass Full ASLR+DEP exploit mitigation

Let's assume that a vulnerabled process is set up with an ASLR and DEP against all the imported modules used in this process and there is no way to find a module that is aslr free.. More over, the ...
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In buffer overflow exploit, 0x20 (space character) not appearing in memory and is replaced by null

The situation: I'm currently working on shellcode (I modified the assembly code from Project Shellcode) that runs "cmd.exe /c calc.exe". The shellcode itself works fine. However, when I use the ...
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Buffer overflow - terminator canaries

I am reading an article on buffer overflow protection here. For terminator canaries, I follow the part that if a terminator like a zero is used for a canary, the attacker would have a terminator in ...
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3answers
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C++ memset() memory overflow

I am new to C++. Can any C++ expert tell me would this causing buffer overflow? Sample Code: MyObject op; memset(&op, 0, sizeof(MyObject)); On my view it is ok to be this since the limit is ...
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1answer
262 views

What should you do if you cannot spawn a shell in a buffer overflow attack?

I have successfully exploited a program using ret2libc but I am running into a problem. Whenever I feed system() with /bin/sh I have nothing in return the program silently exit. However, if I feed ...
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Are stack buffer overflows even possible in this instance?

Let's say there is a C program that simply takes a string argv[1] and uses sprintf to copy it in a finite buffer. Classic stack buffer overflow. Let's even say the program is more complicated, ...
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610 views

Drive-by downlad VS buffer and stack overflow attacks

Today malware is mainly spread thanks to vulnerabilities exploited in browsers and their plugins. The attackers use JavaScript to target those vulnerabilities. Two examples of such attacks are drive-...
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393 views

Does glibc use canary checking to prevent heap buffer overflow?

Since canary is used by gcc to prevent stack overflow (e.g. -fstack-protector), I am wondering whether glibc uses canary-based approach to defend heap buffer overflow? For example, this paper proposes ...
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In return to libc how do you know the address of system() in a remote machine?

I have the following scienarion: a vulnerable program running in a server and can be accessed using netcat I have a copy of that program locally and I can exploit it locally using ROP: ./vuln ...
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Return-oriented programming: how to find a stack pivot

I have a program with a heap overflow. It contains some code that is not randomized (is not using ASLR). I want to do a return-oriented programming exploit. Since this is a heap overflow, the first ...
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4answers
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Adding 65K buffer to protect from buffer overflows?

If you had a very complex and important function in C that you wanted to protect, would it be worth it to put a 65K buffer at the top of the stack to protect from buffer overflows? You would put your ...
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1answer
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Buffer Overflow on Raspberry PI

Is the ARM processor used on the Raspberry Pi vulnerable to standard buffer overflows? That is, if a program that has a BO vulnerability is run on a Pi, will it be vulnerable to exploit? How does ...
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524 views

Fomat String vulnerability used to display data outside the function stack frame?

if we run the following code using the input "hi", the output will simply be "hi" main(int argc, char **argv) { char *secret = "This is a secret 1\n"; char *secret2 = "This is ...
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2answers
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Possible to use buffer overflow on DLL-injected code?

Is it possible to apply buffer overflow on code that was injected using DLL injection? For instance, if I inject a function foo() into the process, is it possible to call foo() using buffer overflow? ...
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Heap canaries, to protect function pointers in heap objects

I'm wondering if anyone has previously proposed, evaluated, or deployed the following measure to harden systems against heap-based buffer overruns: basically, stack canaries, but applied before ...
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645 views

Heap spray against 64-bit processes - possible?

Are heap spray exploits possible, if the process we're attacking is a 64-bit process? Naively, it seems like the 64-bit address makes it difficult to mount a heap spray: to fill all (or a significant ...
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Why are countermeasures against control-flow hijacking attacks mostly implemented in software?

I wonder why countermeasures against code-injection and control-flow hijacking attacks (e.g. stack-based buffer overflows and heap-based buffer overflows) are mostly implemented in software. Examples ...
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539 views

Information disclosure attack, using a heap overflow

A typical strategy for defeating ASLR is to find both a buffer overflow bug and an information disclosure bug. But when attacking servers that are automatically restarted whenever they crash/die, is ...
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144 views

libraries alternative to gcc stack-protector / fortity source feature on linux

is there external library/approach/whatever to add canary protection (stack-protector equivalent) extra buffer boundary check (fortity source equivalent) on a C software without using glibc / ...
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Stack-based buffer overflow the program is interpreting the shellcode on its own

I'm beginner in exploits. So I had type simple program in C #include <stdio.h> void func(){ printf("asd"); } main(){ char buf[100]; scanf("%s", &buf); } My goal is to run the ...
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Buffer Overflow Exploit Shellcode for Windows

Using a buffer overflow, I have been able to override return addresses. But the problem is that Windows addresses contain zeros at the beginning (e.g. 0x00401020). As a result, the objdump of any C ...
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225 views

Does ASLR protect against a buffer overflow within a struct?

Assume a simple struct: struct test { char variable[4]; char variable2; } If I write something like variable[4] = '\0' there is a buffer overflow which modifies variable2. Does ASLR prevent ...
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Would the Heartbleed bug have been prevented if OpenSSL was written in Go/D/Vala?

IIUC the Heartbleed vulnerability happens due to a bug in the C source code of OpenSSL, by performing a memcpy() from a buffer that is too short. I'm wondering if the bug would have been prevented ...
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Defend against Blind ROP

At IEEE Security & Privacy, the blind return-oriented programming attack (blind ROP) was just introduced. In some sense, this is just another variation on ROP attacks -- but the blind ROP attack ...
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Why is it so difficult to protect an application against buffer overflows?

For example, buffer overflow vulnerabilities in Flash are often discovered. Shouldn't a proper verification of all function parameters in Flash source code be enough to protect against buffer ...
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How does SEH based exploit bypass DEP and ASLR?

I am new to structured exception handling based exploits. Why don't we put our return address directly in SE handler to jump to our shellcode? (with no safe SEH) Can anybody explain the reason of ...
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Should I worry about this UAC bypass exploit for Windows 7?

It appears that there is an exploit out there that allegedly allows you to bypass the UAC on Windows 7 computers and gain administrator access. I was wondering if this exploit is still a dangerous ...
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How to explain buffer overflow to a layman

Every once in a while (when I think out loud and people overhear me) I am forced to explain what a buffer overflow is. Because I can't really think of a good metaphor, I end up spending about 10 ...
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Is writing shellcode still a valid skill to have/learn?

Following up from this question: Should I bother teaching buffer overflows any more? I am a it sec researcher and also security course instructor. Recently questions have been raised about the ...
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How to get this to buffer overflow?

I'm trying to understand buffer overflow, and am working with a simple piece of code, as below. #include <stdlib.h> #include <stdio.h> #include <string.h> int bof(char *str) { ...
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Bypass va_randomize_space and stack-protector

Is a program compiled with the GCC -fstack-protector option and running in a Linux environment with the va_randomize_space kernel variable set to 1, totally protected against buffer overflow attacks? ...
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Python exploit question?

Can someone please explain how and why this struct.pack code is used in the below exploit? I'm trying to understand how it triggers the vulnerability. I understand the buffer overflow aspect, I'm ...
2
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1answer
614 views

EIP pointer is overwritten but EBP remains intact

I was trying out a simple stack buffer overflow exploit by creating a malicious crash.m3u file. as you can see the EIP pointer is overwritten by "A" but EBP hasn't changed. isn't EBP supposed to get ...
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369 views

Using buffer overflow on word with macro injection

I know how a buffer overflow works on a local network against an application running on a TCP port, assuming it doesn't drop the connection, but I would like some advice on an "exploit" I would like ...
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1answer
450 views

Why does this buffer overflow have payload &system-&exit-&BINSH

I'm following a tutorial to write a simple buffer overflow. I have (basic) knowledge of assembly, and the stack. I've written a stack based buffer overflow before and understood it. The program I'm ...
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Inversed Data Direction on the Stack

As I remember from my micro controller course, the stack is at the end of the memory, while at the begin are some interrupt pointers, program code and later data. Since the stack is at the end of the ...
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Examples of images causing buffer overflows? [closed]

I remember reading a news article of an incident where a hacker was able to use an image to infect thousands (maybe millions?) of computers. Can anyone provide links to such news articles? I couldn't ...
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NX bit: does it protect the stack?

I once heard the NX bit was a panacea, then that it was not. One detail I've wondered about though: Does the NX (no execute) bit protect against code inserted into the stack and executed there? It ...
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Tracking down the source of email attacks

For the past week our company's IDS has been blocking 100-200 meeting invite emails per day from a specific client that are loaded with buffer overflows targeted at Exchange 2003. The payloads are ...