The C programming language, commonly used for low-level programming

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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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107 views

How to know the time of compilation

I've read that a malware found by kaspersky was compiled at the moscow time zone. How they know the time of compilation ?
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310 views

how does a return to system allow an attacker to evade a non-executable stack?

I am learning about return to system call attacks for a security class. I understand that in this kind of attack, attackers replace the standard return value for a stack frame with the address of a ...
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1answer
2k views

Are there any functional differences in the implementations of OpenSSL, GnuTLS, Java's TLS, and .NET's TLS?

Question Are there any functional (or detectable) differences between the various implementations of SSL/TLS? What are the differences between them? (e.g. which ones implement "False Start") ...
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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
3k views

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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1answer
328 views

Best option to fuzz a C Network Program [closed]

I have a client/server simple program in C. I want to test the server running on different machine with random inputs. I have looked at 'Bunny-the-fuzzer' but from what I can understand It wont be ...
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85 views

C program - exploit program (after seg fault)

The program below takes three parameters - Base to convert from, base to convert to and the number to convert in binary As part of learning security - I am trying to buffer overflow this program. I ...
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104 views

How to encrypt and authenticate large amounts of data with NaCl

In a current project the NaCl-library crypto_box function has been used to encode and crypto_box_open to authenticate and decode data. However the library does not seem to support de- / encoding of ...
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2answers
311 views

What's the secure way to change UNIX permissions on a harcoded file often?

I'm writing a daemon that monitors something in the OS and flips execution permissions on a file in /run/ back and forth. The file has static contents and the file name is hardcoded in the daemon. I ...
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3answers
1k views

Top 10 dangerous mistakes in C programming? [closed]

What is the top dangerous mistakes in C programming? for example misusing a strcpy causes a stack-overflow and code injection. I'm looking for at least 10 bad programming pattern in C.
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3answers
145 views

How can I execute shell in this CTF exercise?

I am playing a CTF wargame and unfortunatley got stuck at this level, so I want to "crowdsource" it. No need for complete answer, but hints would be enough. How can I: Make strcmp to be 0 (evaluate ...
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2answers
861 views

How do I make a working example of a “Dangling Pointers” exploit? (or where do I find it online)

I was recently reading about buffer overflows and dangling pointers. I read "Smashing the stack for fun and Profit " by Aleph1 and that paper was really clear and concise in explaination. On the ...
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1answer
8k views

How to learn programming from a hacker's prospective [closed]

I'm really into hacking and security aspects. But I'm wondering about several things that is stopping me from pursuing this passion for the time being. One of the them is actually Programming ...
2
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1answer
476 views

Is there a way to identify the client using SSL Handshake Messages?

I have an SSL Server and it can be connected by two types of Clients, one for which Client Authentication is needed and the other for which Client Authentication is not needed. Is there any mechanism ...
2
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1answer
72 views

How can I find the size of an array just from compiled C program?

I'm playing around with buffer and heap overflow vulnerabilities, and it is all fine to exploit stuff when you have the source code and can see all the variables, their sizes and values, etc. But, ...
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2answers
100 views

when defining constants, is #define more secure than static const?

I want to have some constant values in my program, for example, I have a constant value TimeLimit in a header which is commonly used in other classes, but I don't know if #define TimeLimit 30 is ...
2
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1answer
114 views

PHP BLENC extension security concern

PHP BLENC is a extension that allows PHP developer encrypt their code, protect their ideas and avoid illegal copy. Although BLENC allow developer to define the main encryption key in source(in the ...
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1answer
104 views

Should I compile as root?

When I am compiling software for local installation, what factors should I take into consideration when deciding whether to compile as root or to compile under my regular user account? ./configure ...
2
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1answer
127 views

How to exploit this piece of code? (format string in printf?) [closed]

So this piece of code is vulnerable to format string vuln (I think) in the printf() function. It reads a file in /tmp/file so I've tried writing different modifier/strings in that file and see what ...
2
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1answer
375 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; ...
2
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1answer
305 views

SSH Protocol classification version exchange messages

I am trying to classify network protocols over network traffic . Now my task is SSH protocol. I read the RFC and know SSH starts with protocol exchange message from both client and server . Format ...
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0answers
64 views

Snort Portscan Preprocessor Analysis

Remarks I really apologize if this content isn't matching the community, but I am not getting approved on snort-mailing lists and I don't know what can I do for the same, therefore I feel this can be ...
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2answers
398 views

Is a C plugin safe if I read it through an echoing parser before?

I wanted to use sharable plugins for an application. However, the plugins were extremely time critical, so I wanted to distribute them as C libraries. Now, these are not guaranteed to be safe (the ...
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3answers
88 views

Since when can't any program get MS-DOS and MS-Windows admin rights?

I'm certain that I read that in the 80s with 8-bit Intel processorn, any DOS program that was run with MS-DOS was run in administrative mode and could do anything that any C program could do. Now I'm ...
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1answer
374 views

MySQL/CGI: password in C source file unsafe?

Is this line bad practice from a security stance? connect = mysql_real_connect(connection, "host", "user", "password", "database", 0, (const char *)NULL, 0); If so, what solution would you use? ...
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3answers
653 views

OpenSSL encrypting small packets bandwidth overhead

I have an c/c++ program used for encrypting data for communicating between two ends. Encryption is done using OpenSSL (0.9.8d-fips, Sep 2006). Think it'll be worthy to mention that I'm not much ...
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1answer
79 views

Unsafe C program accepting malicious string inputs

I have a question regarding to this unsafe C program. int main(int argc, char **argv) { char text[32]; static int some_value = -72; strcpy(text, argv[1]); /* copy the parameter into the ...
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2answers
494 views

Seeking lightweight encryption - shareable between Delphi & C

I want to encrypt a text file in Delphi & decrypt it, line by line, in C on an embedded system which does not have much RAM (so, only one line in RAM at a time). FOSS must be available for both ...
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1answer
374 views

Which software scans software for potential vulnerabilities?

Is there any kind of parser-software-analysis tool that will analyze c code and outputs possible vulnerabilities like buffer oveflows?
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51 views

Static vs Dynamic Linking

I came across DJB's Curve25519 implementation site (https://cr.yp.to/ecdh.html) and noticed he states in reference to using it: You can and should include it in your own programs, rather than ...
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2answers
459 views

Is `arc4random` secure enough?

I need to generate many many initialization vectors and session keys in C++ code. I am wondering if arc4random is up to the task. Last I heard, there are many weaknesses in the RC4 cipher. Should I ...
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1answer
452 views

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 hdr-&...
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1answer
32 views

Expand user login in Path - Filter malicious values

I have a function that takes a pathname and substitutes every occurrence of '%u' with a given String. For my scenario this given String is the login that a user/attacker enters via ssh during ...
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1answer
2k views

Starting a new shell in a strcpy exploit using buffer overflow

I'm learning about buffer overflows and have this vulnerable code which I'm trying to start a shell from: #include <string.h> void myfunction(char *arg); int main(int argc, char **argv) { ...
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1answer
83 views

Is or was it possible to register a wildcard certificate to third level subdomain?

The use of a null byte in a certificate cn is very well known… and I saw this code in a popular smtp server (who obviously thought it didn’t worth to use the gnutls or openssl for doing that kind of ...
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1answer
36 views

Non-identified algorithm for RSA decryption in tpm-emulator

While analyzing the source code of tpm-emulator I found that the RSA key decryption uses an algorithm that is unknown to me. The original file with this mystery is located in rsa.c, where the ...
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snort spp_sfPortscan Preprocessor Customization [closed]

I am working in snort 2.9.8.0. I want to modify the snort code for Portscanning Detection,i.e spp_sfPortscan.c and its related code to build a customized portScan detector. Ex:suppose A is scanning ...
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880 views

verifying digest signed with private key using a C program

I'll explain all the steps I've done so far and conclude with my question. using OpenSSL 1.0.1e-fips 11 Feb 2013 Generating a private and public key openssl genrsa -des3 -out private.pem 2048 ...
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97 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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187 views

Problem in understanding Blakley's Secret Sharing Scheme

I need to implement Blakley's Secret Sharing Scheme. I have read below mentioned two research papers but still unable to understand how to implement it. 1. Safeguarding cryptographic keys 2. Two ...
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1answer
2k views

Why aren't sophisticated Malware written with .NET [closed]

I've been trying to research malware techniques lately, as malware analysis intrigues me. I've got a pretty heavy background in .NET, and based on my 7+ years in .NET, I feel that I could write a ...
0
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1answer
139 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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1answer
315 views

Good reading about windows architecture/reversing [closed]

I have a feeling that I need to get more knowledge about system programming and winapi/windows architecture in particular to be able to understand how lots of exploits work (like those exploiting ...
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0answers
49 views

Why there is no shell prompt by exploiting this script?

I tried to get a shell prompt in the following vulnerable code, I think that I found the vulnerability, actually it is a simple stack buffer overflow, but now I have a problem with exploiting the ...
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0answers
34 views

Rootkit driver to change executed instructions

Say I have a process that has a bunch of functions I want to NOP out. From userland, I want anyone viewing the virtual memory to see the normal instructions. However physical memory, and in the end ...
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260 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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1answer
141 views

Shellcode to buffer overflow not working linux m32

What my purposely insecure program does is to check if a username matches a specific string by copying user input into a buffer and comparing it. I have compiled the program cc -o real real.c -g -...
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There could be still buffer overflows in ex.: C?

I recently read about the $subject. Q: Why does a programming language has built-in trivial insecurity? Or.. it was just in the old times? How could this be?
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2answers
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Generate openSSL certificates from within C code using commands?

This is an openSSL command for generating a private key and a certificate, openssl req -out CSR.csr -new -newkey rsa:2048 -nodes -keyout privateKey.key The question I have is whether there is some ...