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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Buffer overflow lab problem [migrated]

Since our security course doesn't have a lab, i'm trying to solve the Seed project's lab . http://www.cis.syr.edu/~wedu/seed/Labs_12.04/Software/Buffer_Overflow/Buffer_Overflow.pdf But there seems ...
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Understanding and trying out buffer overflow attacks [on hold]

I came to read this article (It's a bit old) demonstrating stack based buffer overflow attack in an unpatched version of Windows XP Service Pack 1 (Later versions of Windows are reasonably secure to ...
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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 ...
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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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is return-to-libc attacks possible Now?

I'v read that to make a successful return to lib-c attack, the attacker should store the address of the command (for example "bin/sh") in stack exactly after the return address to 'system' function ...
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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, ...
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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 ...
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Evading IDS in exploit development

In the context of buffer overflow exploit development, I was asked: Discuss how your exploit may be modified to evade an Intrusion Detection System. I'm not asking for my homework to be done, but ...
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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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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 ...
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EIP getting changed in fgetc() Buffer Overflow Homework

Here is the gist of the code: main(){ char s1[64], s2[64]; int a = 0, b = 0; FILE *fp1, fp2*; char temp; scanf("%s", s1); scanf("%s", s2); ... //some checks happen, fp1 is opened to ...
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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
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Does preventing buffer overflow attacks prevent ROP attacks?

Would preventing buffer overflow attacks prevent Return Oriented Programming (ROP) attacks?
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Why are buffer overflows executed in the direction they are?

I'm following The Security Tube’s video here. He overviews buffer overflows, and mentions how memory is executed from highest to lowest in the stack (at least with his implementation I assume). So we ...
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1answer
45 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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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 ...
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2answers
163 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
24 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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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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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 ...
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2answers
124 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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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 ...
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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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116 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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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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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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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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516 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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137 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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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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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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Is OpenSSL 0.9.8h affected by CVE-2014-0195?

I have spent time on finding out if OpenSSL 098h is affected by the CVE-2014-0195 ..but it seems I will have to understand the entire file d1_both.c to answer this question. 1) Preliminary look at ...
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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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263 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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241 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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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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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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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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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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2answers
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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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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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Examples of software web clients (web browsers, IM clients, etc) written in “secure” / managed languages

After reading this article ("Everything is broken" by Quinn Norton) I was about to ask a question similar to this one (Why are security-crucial software written in unsafe languages?)... but actually I ...
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242 views

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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314 views

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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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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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 ...