REMOTE promiscuous ethernet detector. For Red Hat 5.x.
312bb500df187faebd8c6747a304c995827d282d78bc2d9dd01e70cd7b092a7e
/* -----------------------------------------
REMOTE promiscuous ethernet detector.
Compiles and runs ok on RH5/GlibC
-----------------------------------------
(c) 1998 savage@apostols.org
-----------------------------------------
Scan your subnet, and detect promiscuous
machinez. It really works, not a joke.
----------------------------------------- */
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <malloc.h>
#include <ctype.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netinet/tcp.h>
#include <net/if.h>
/*#include <net/ethernet.h>*/
#include <linux/if_ether.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <time.h>
#define MAX_PACK_LEN 2000
#define ETHER_HEADER_LEN 14
#define ARPREQUEST 1
#define ARPREPLY 2
#define perr(s) fprintf(stderr,s)
struct ether_hdr
{
u_char dst_mac[6], src_mac[6], pkt_type[2];
u_short hw_type, pro_type;
u_char hw_len, pro_len;
u_short arp_op;
u_char sender_eth[6];
u_char sender_ip[4];
u_char target_eth[6];
u_char target_ip[4];
};
union
{
u_char full_packet[MAX_PACK_LEN];
struct ether_hdr ether_header;
}
a;
#define full_packet a.full_packet
#define ether_header a.ether_header
char *
inetaddr ( u_int32_t ip )
{
struct in_addr in;
in.s_addr = ip;
return inet_ntoa(in);
}
char *
hwaddr (u_char * s)
{
static char buf[30];
sprintf (buf, "%02X:%02X:%02X:%02X:%02X:%02X", s[0], s[1], s[2], s[3], s[4], s[5]);
return buf;
}
void
main (int argc, char **argv)
{
int rec;
int len, from_len, rsflags;
struct ifreq if_data;
struct sockaddr from;
u_int8_t myMAC[6];
u_int32_t myIP, myNETMASK, myBROADCAST, ip, dip;
if (geteuid () != 0) {
perr ("You must be root to run this program!\n");
exit (0);
}
if (argc != 2)
{
perr ("Usage: scanpromisc eth0\n");
exit (0);
}
if ((rec = socket (AF_INET, SOCK_PACKET, htons (ETH_P_ARP))) < 0)
{
perror("socket");
exit (0);
}
printf ("----------------------------------------------------------\n");
strcpy (if_data.ifr_name, argv[1]);
if (ioctl (rec, SIOCGIFHWADDR, &if_data) < 0)
perr ("can't get HW addres of my interface!\n");
memcpy (myMAC, if_data.ifr_hwaddr.sa_data, 6);
printf ("> My HW Addr: %s\n", hwaddr (myMAC));
if (ioctl (rec, SIOCGIFADDR, &if_data) < 0)
perr ("can't get IP addres of my interface!\n");
memcpy ((void *) &ip, (void *) &if_data.ifr_addr.sa_data + 2, 4);
myIP = ntohl (ip);
printf ("> My IP Addr: %s\n", inetaddr(ip));
if (ioctl (rec, SIOCGIFNETMASK, &if_data) < 0)
perr ("can't get NETMASK addres of my interface!\n");
memcpy ((void *) &ip, (void *) &if_data.ifr_netmask.sa_data + 2, 4);
myNETMASK = ntohl (ip);
printf ("> My NETMASK: %s\n", inetaddr(ip));
if (ioctl (rec, SIOCGIFBRDADDR, &if_data) < 0)
perr ("can't get BROADCAST addres of my interface!\n");
memcpy ((void *) &ip, (void *) &if_data.ifr_broadaddr.sa_data + 2, 4);
myBROADCAST = ntohl (ip);
printf ("> My BROADCAST: %s\n", inetaddr(ip));
printf ("----------------------------------------------------------\n");
printf("> Waiting for an ARP pkt (don't ask why) ... "); fflush(stdout);
len = recvfrom (rec, full_packet, MAX_PACK_LEN, 0, &from, &from_len);
printf("Ok!\n");
if ((rsflags = fcntl (rec, F_GETFL)) == -1)
{
perror ("fcntl F_GETFL");
exit (1);
}
if (fcntl (rec, F_SETFL, rsflags | O_NONBLOCK) == -1)
{
perror ("fcntl F_SETFL");
exit (1);
}
printf ("----------------------------------------------------------\n");
printf ("> Scanning ....\n");
for (dip = (myIP & myNETMASK) + 1; dip < myBROADCAST; dip++)
{
memcpy (ether_header.dst_mac, "666666", 6);
memcpy (ether_header.target_eth, "\0\0\0\0\0\0", 6);
ip = htonl (dip);
memcpy (ether_header.target_ip, &ip, 4);
memcpy (ether_header.src_mac, myMAC, 6);
memcpy (ether_header.sender_eth, ether_header.src_mac, 6);
ip = htonl (myIP);
memcpy (ether_header.sender_ip, &ip, 4);
ether_header.arp_op = htons (ARPREQUEST);
ether_header.hw_type = 0x0100;
ether_header.hw_len = 6;
ether_header.pro_type = 8;
ether_header.pro_len = 4;
if( sendto (rec, full_packet, sizeof (struct ether_hdr), 0, &from, from_len) < 0)
perror ("sendto");
usleep (333);
len = recvfrom (rec, full_packet, MAX_PACK_LEN, 0, &from, &from_len);
if (len <= ETHER_HEADER_LEN)
continue;
memcpy (&ip, ether_header.target_ip, 4);
if (ntohs (ether_header.arp_op) == ARPREPLY
&& ntohl (ip) == myIP)
{
memcpy (&ip, ether_header.sender_ip, 4);
printf ("*> Host %s, %s **** Promiscuous mode detected !!!\n",
inetaddr (ip),
hwaddr (ether_header.sender_eth));
}
}
printf ("> End.\n");
exit (0);
}