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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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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How can vending machines be hacked? And how can I prevent it?

I am developing a vending machine and want to make it secure. In a comment to my previous question, @Polynomial said "Vending machines (and similar devices) can often be pwned via buffer overflows on ...
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102 views

sigsegv in php5.3.10

I found an overflow situation in php5.3.10. Probably it's not 'something new', but if I can understand this, it will help me to find this kind of bug faster in the future. What can I do to check ...
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SafeSEH and x64

I read here that /SAFESEH is only valid when linking for x86 targets. /SAFESEH is not supported for platforms that already have the exception handlers noted. For example, on x64 and Itanium, ...
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482 views

Stack canaries protection and ROP

As far as I know stack canaries are values written on the stack that, if overwritten by a buffer overflow, force the application to close at return. My question is: if I overwrite both EIP and stack ...
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Do I always have to overwrite EIP to get to write on the stack in a buffer overflow?

Do I always have to overwrite EIP to get to write on the stack in a buffer overflow? How's the memory organized? I can't find a proper graph with google
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1answer
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“Hello World” example of a Buffer Overflow attack in many programming languages

I'm looking for a very simple application that has an intentional Buffer Overflow embedded in it. I'm assuming this possible in systems where DEP and ASLR are not being used Ideally (and if ...
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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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1answer
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Stack smashing keep getting segmentation fault

I have a homework assignment to do stack smashing, The exploit code creates a badfile in which the vulnerable file reads and buffer over flow occurs. I have already did the 2 commands below to ...
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1answer
392 views

How to completely prevent bufferoverflows in networking software?

Is that possible to make software which is not vulnerable to any type of buffer overflow? For example, a software that receives data packets and transfers it to destination after data analysis.
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Determining the target address in a heap overflow

For a heap overflow to occur and arbitrary code to be executed, the function free() performs the step : hdr->next->next->prev = hdr->next->prev I understand that the address of ...
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Stack Overflows - Defeating Canaries, ASLR, DEP, NX

To prevent buffer overflows, there are several protections available such as using Canary values, ASLR, DEP, NX. But, where there is a will, there is a way. I am researching on the various methods an ...
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Why don't computers check whether there are memory contents in some memory space?

Buffer overflow occurs because it writes to memory spaces that are used by, or will be used by other parts of the program. Computer programs usually write to the memorylocation that has been ...
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2answers
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Any reasons to why not use randomize_va_space?

I've been looking a bit into kernel options for hardening, and there is one that seems to be a good idea to deploy - randomize_va_space. But before I activate that feature I started a google search, ...
10
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2answers
660 views

AMD64 overflows and null bytes

In the past, I have managed to overflow my own vulnerable programs, and those of others, but only ever in a 32bit environment. Every time I try even a simple stack smash on a 64bit machine, I run into ...
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1answer
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Dangers of a vulnerability in a local installer?

I sent a message to my dev manager about a buffer overflow in our (widely distributed) installer, and received a response that it didn't matter as it wasn't server code. Other than the fact that if ...
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1answer
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What to do next for this possible buffer overflow?

I've been instructed to test a few of our newer applications before user release, and managed to find a buffer overflow on one of the fields. Here is where I've run into a brick wall though, and ...
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1answer
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buffer/heap overflow - register of what is executed

When buffer overflow/heap overflow is executed, is EIP the one that tells which part will be executed next? Also, when exploiting the part that has buffer overflow vulnerability, after execution, will ...
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1answer
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php_register_variable_ex vulnerability question

Vulnerability I am referring to is: http://www.securityfocus.com/bid/51830 And here in more detail: http://auntitled.blogspot.com/2012/02/mini-poc-for-php-rce-cve-2012-0830.html So basically what ...
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Snort false positive?

I've set up snort and am configuring it for my network. I have one vpn server making a connection to my dns/AD server. This connection sets off: GPL SHELLCODE x86 inc ebx NOOP The payload is as ...
7
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1answer
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Sulley - optional element and command check

I'm currently using Sulley to fuzz my FTP server, but I'm having problems. I want to specify the STRU command, which has a syntax: STRU [<SP> F|R|P] <CRLF> I tried to specify the ...
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3answers
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Finding environment variables with gdb, to exploit a buffer overflow

I have to exploit a very simple buffer overflow in a vulnerable C++ program for an assignment and I am not being able to find the environment variable SHELL. I have never worked with BoF before, and ...
5
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How do attackers gather remote feedback for identifying and exploiting buffer overflows?

Local buffer overflows are relatively easy to understand: throw some input at an interface and see if the process fails with a core dump or similar. However, in my mind, this kind of exploit works ...
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Why do I get “Cannot find bound of current function” when I overwrite the ret address of a vulnerable program?

I want to exploit a stack based buffer overflow for education purposes.There is a typical function called with a parameter from main which is given as input from the program and a local buffer where ...
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2answers
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Difference between vulnerabilities on windows/linux/mac for same program

If someone finds a vulnerability like buffer overflow in a program such as Google Chrome or Mozilla Firefox running on a linux machine, are there any chances that this vulnerability will persist on ...
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What programming language does this code use?

Watching this article: http://www.exploit-db.com/exploits/13474/ I can see this: /* * NetBSD * execve() of /bin/sh by humble of Rhino9 */ char shellcode[] = "\xeb\x23" "\x5e" "\x8d\x1e" ...
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Remote return into libc attack

It is often shown that non-executable data segemnts are possible to bypass through return-to-libc attacks. It's evident on /bin/sh but is it also possible to invoke a remote shell?
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Does compiling from sources “kinda” protects from buffer overflow attacks?

While discussing buffers overflows, somebody told me that compiling your own binary for an application (with specific compilation flags) instead of using the "mainstream binary" makes it more ...
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Secure memcpy for pure C

Buffer overflows are nothing new. And yet they still appear often, especially in native (i.e. not managed) code... Part of the root cause, is usage of "unsafe" functions, including C++ staples ...
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Should I bother teaching buffer overflows any more?

The students are skeptical that turning off non-executable stacks, turning off canaries and turning off ASLR represents a realistic environment. If PaX, DEP, W^X, etc., are effective at stopping ...
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Bypassing Address Space Layout Randomization

How effective is ASLR in preventing arbitrary code execution in a buffer overflow type exploit? How hard is it for an attacker to bypass this without simply guessing where the addresses are?
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Does using many XML parsers (XDocument, XMLDocument) from the public Internet increase attack surface area?

I am coding an anonymous WCF service that allows others to post XML into it. Does using different kinds of XML parsers XDocument, XMLDocument, or even 3rd party parsers increase the attack surface ...