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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stack buffer overflow in the main function? [closed]

I am trying to exploit a stack based overflow vulnerability. All the examples I can find make use of a ret address though. The buffer overflow I found is inside the main function, and I cannot find ...
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Having trouble reproducing PHP heap based buffer overflow in quoted_printable_encode [closed]

I am trying to follow the test script provided here. I've installed an apache web server with PHP version 5.3.25 and created a script with the following code: <?php // file: test.php $str = ...
3
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1answer
289 views

Why should canary values be chosen at runtime instead of compile time?

For buffer overflow attacks, my exam review says that there are drawbacks to choosing canary values at compile time vs runtime. Why would it be better to choose the canary value at runtime?
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34 views

Can you get infected by viewing an image? [duplicate]

Lets say I have an infected image by some malware, I double-click it and that triggers the default program that handles images to open it for viewing. Will this also trigger the malware inside the ...
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0answers
261 views

how does ASLR prevent return to libc / ROP and similar attacks?

I am trying to understand ASLR and how it is implemented. I understand it does not actually "prevent" buffer overflow etc from happening, it will only make it more difficult. But i am not able to ...
6
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1answer
246 views

Return oriented programming without int 0x80

I have a program with a stack based buffer overflow. It is running PIE with ASLR and DEP, however there is a section of executable code that is at a fixed location. However, this region does not ...
3
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1answer
292 views

exploiting Heap Overflow in gdb segfaults

I have been trying to exploit the heap overflow vulnerability for the program below, I am running Linux 14.04. #include <stdio.h> #include <string.h> #include <stdlib.h> int n = 5; ...
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0answers
107 views

ROP attack on x64, zero bytes trouble

I have found ROP tutorial on x86. Now i try to exploit simple buffer overflow case on x64: int main(int argc, char **argv) { char buf[10]; strcpy(buf, argv[1]); ... } I figured out, ...
3
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1answer
211 views

How to find stack pointer for overflow bug?

I've read that stack usually starts in same address so the attacker may guess the starting point of the buffer to overflow. This is necessary to know this address to make the malicious code run. I ...
2
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1answer
74 views

Buffer Overflow and Segments

I know by overwriting the return address in vulnerable program we can change the offset of next instruction and make it to point to our injected buffer. but this buffer is in stack segment and the ...
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0answers
36 views

unable to execute shellcode,which is place on stack [duplicate]

I am trying to execute the shellcode to spawn an "sh" shell. I have taken shellcode as command line arguement,copied it to stack and tried to overwrite the return address of main function with the ...
36
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2answers
7k views

What is the most hardened set of options for GCC compiling C/C++?

What set of GCC options provide the best protection against memory corruption vulnerabilities such as Buffer Overflows, and Dangling Pointers? Does GCC provide any type of ROP chain mitigation? Are ...
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66 views

Constructing a tainted string for arc injection

I'm new to security and currently referring to Robert Seacord's Secure Coding in C and C++. In chapter 2 of the same, the author talks about arc injection, wherein he passes the flow of control in the ...
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2answers
114 views

Does preventing buffer overflow attacks prevent ROP attacks?

Would preventing buffer overflow attacks prevent Return Oriented Programming (ROP) attacks?
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1answer
75 views

Are Sun/Oracle's SPARC processors invulnerable to buffer overrun exploits?

We all use Intel architectures these days, in small part because Oracle has totally dropped the ball regarding SPARC CPU development. But with so many now saying that protection against viruses is ...
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0answers
166 views

Exploiting buffer overflow

When I download a copy of a vulnerable program and try to exploit it by buffer overflow (any internal function calling as a payload), it works. However, when I made a same type of vulnerable program ...
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0answers
73 views

When is memory allocation/layout deterministic?

I'm trying to learn about buffer overflow attacks, both on the stack and on the heap. However, I'm confused about when it's possible to determine the address of the buffer. The classic "Smashing the ...
5
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2answers
602 views

On Hawkes' technique to bypass canaries

I found this reference to bypass canaries: http://sota.gen.nz/hawkes_openbsd.pdf It recommends to brute force the canary byte-for-byte. I don't understand how this works: "Technique is to brute force ...
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1answer
687 views

Program exiting after executing int 0x80 instruction when running shellcode

In school I was given an assignment to perform a buffer overflow, which would execute some shellcode and open a new shell. After a bit of fiddling the buffer overflow succeeded, and when I ran the ...
4
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2answers
397 views

Long character sequence in first string of HTTP GET request breaks the web service's HTTP response. Buffer overflow?

During my current security audit test I've stumbled on something I can't possibly comprehend. The behavior exhibits signs of a buffer overflow in the target or in some intermidiate service (HTTP ...
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1answer
116 views

Getting a DEP exception when trying to call SetProcessDEPException(false)

I'm demonstrating an exploit for an old app. On Windows XP SP3 32bit (EN), the address of SetProcessDEPPolicy() is usually 0x7C8622A4. I have that version of Windows (in English as well) and I've ...
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0answers
223 views

Stack buffer overflow: Is compiler changing variables order, preventing me to overwrite EIP properly?

I am learning about stack buffer overflow. A little info about my target: A x86 little endian intel-based computer, with a target compiled with TCC Compiler with no protections of any kind running on ...
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2answers
85 views

8 extra bytes in stack

i am new to buffer overflow and learning from securitytube.net website but in 7th video i got stucked Buffer Overflow Primer Part 7 (Exploiting A Program Demo) In this when the value of egg is passed ...
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1answer
133 views

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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0answers
54 views

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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3answers
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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 ...
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1answer
796 views

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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2answers
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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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2answers
690 views

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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2answers
414 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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4answers
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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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3answers
2k views

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> ...
12
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1answer
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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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1answer
144 views

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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1answer
409 views

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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1answer
431 views

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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1answer
2k views

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
944 views

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 ...
2
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1answer
241 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 ...
2
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1answer
117 views

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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591 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 ...
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1answer
269 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 ...
0
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1answer
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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 ...
15
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1answer
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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 ...
11
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4answers
2k views

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
906 views

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 ...
0
votes
1answer
427 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
219 views

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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2answers
390 views

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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2answers
525 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 ...