Another WMF flaw without a Microsoft patch

["Richard M. Smith" <rms () computerbytesman com>]

-----Original Message-----
From: frankruder () hotmail com [mailto:frankruder () hotmail com] 
Sent: Saturday, January 07, 2006 12:08 AM
To: bugtraq () securityfocus com
Subject: Microsoft Windows GRE WMF Format Multiple Memory Overrun
Vulnerabilities

Microsoft Windows GRE WMF Format Multiple Memory Overrun Vulnerabilities

by cocoruder
page:http://ruder.cdut.net
email:frankruder_at_hotmail.com

Last Update:2006.01.07
class:design error
Remote:yes
local:yes

Product Affected:
Microsoft Windows XP SP2
Microsoft Windows XP SP1
Microsoft Windows Server 2003 SP1
Microsoft Windows Server 2003
Microsoft Windows ME
Microsoft Windows 98se
Microsoft Windows 98
Microsoft Windows 2000SP4

Vendor:
www.microsoft.com

Overview:
Microsoft Windows GRE(Graphics Rendering Engine) has been discovered
multiple memory overrun vulnerabilities while rendering WMF format
file.Users who view the malicious WMF format file will bring a denial of
service attack(explorer.exe will be restart).

Details:
there is 2 memory overrun vulnerabilities at least.

1.ExtCreateRegion call result in memory overrun vulnerability HRGN
ExtCreateRegion(
  CONST XFORM *lpXform,     // transformation data
  DWORD nCount,             // size of region data
  CONST RGNDATA *lpRgnData  // region data buffer );

WMFRECORD structure:
typedef struct _StandardMetaRecord
{
    DWORD Size;          /* Total size of the record in WORDs */
    WORD  Function;      /* Function number (defined in WINDOWS.H) */
    WORD  Parameters[];  /* Parameter values passed to function */ }
WMFRECORD;

the Parameters is likely about:
typedef struct  _Parameters
{
        char    unknow1[0x0a];
        WORD    All_PointtStruct_Num;   //the total following "
PointtStruct" number
        char    unknow2[0x0a];
        char    PointtStruct[];         //first  "PointtStruct"
}Parameters;

"PointtStruct"  structure:
typedef struct  _PointtStruct
{
        WORD    PointNum;               //
        WORD    Point[PointNum];        //
        char    unkonow[6];
}PointtStruct;

if we set 0xff to WMFRECORD.Function,PlayMetaFileRecord will compute the
memory which will be allocate later,as following:

.text:7F00FE07 loc_7F00FE07:                           ; CODE XREF:
PlayMetaFileRecord+1256j
.text:7F00FE07                 sub     eax, 3
.text:7F00FE0A                 jnz     loc_7F022B9A    ; 0xff
.text:7F00FE10                 movzx   ecx, word ptr [ebx+10h]  ;get total
"PointtStruct" number
.text:7F00FE14                 mov     [ebp-88h], ecx           ;save
.text:7F00FE1A                 test    ecx, ecx
.text:7F00FE1C                 jnz     short loc_7F00FE2E       ;jmp 
.text:7F00FE1E                 xor     eax, eax
.text:7F00FE20                 push    eax             ; int
.text:7F00FE21                 push    eax             ; int
.text:7F00FE22                 push    eax             ; int
.text:7F00FE23                 push    eax             ; int
.text:7F00FE24                 call    CreateRectRgn
.text:7F00FE29                 jmp     loc_7F010494
.text:7F00FE2E ;
哪哪哪哪哪哪哪哪哪&#21
738;哪哪哪哪哪哪哪哪哪
哪哪哪哪哪哪哪哪哪&#21
738;哪哪哪哪哪哪哪哪?
.text:7F00FE2E
.text:7F00FE2E loc_7F00FE2E:                           ; CODE XREF:
PlayMetaFileRecord+C15j
.text:7F00FE2E                 xor     edi, edi
.text:7F00FE30                 mov     [ebp-8Ch], edi
.text:7F00FE36                 lea     eax, [ebx+1Ch]           ;get first
"PointtStruct" address
.text:7F00FE39                 mov     [ebp-90h], eax           ;save
.text:7F00FE3F                 and     [ebp-94h], edi                   
.text:7F00FE45                 and     [ebp-98h], edi
.text:7F00FE4B                 test    ecx, ecx
.text:7F00FE4D                 jbe     short loc_7F00FE8C               
.text:7F00FE4F
.text:7F00FE4F loc_7F00FE4F:                           ; CODE XREF:
PlayMetaFileRecord+C83j
.text:7F00FE4F                 movzx   ecx, word ptr [eax]      ;get
PointNum,here will trigger memory access error**
.text:7F00FE52                 mov     edx, ecx                         
.text:7F00FE54                 shr     edx, 1                   ;PointNum/2
.text:7F00FE56                 add     edx, edi                 ;sum
PointNum/2
.text:7F00FE58                 cmp     edx, edi
.text:7F00FE5A                 jb      loc_7F0106D5
.text:7F00FE60                 mov     edi, edx
.text:7F00FE62                 mov     [ebp-8Ch], edi
.text:7F00FE68                 cmp     ecx, 7FFFFFFBh
.text:7F00FE6E                 jnb     loc_7F0106D5
.text:7F00FE74                 lea     eax, [eax+ecx*2+8]
.text:7F00FE78                 inc     dword ptr [ebp-98h]      ;counter+1
.text:7F00FE7E                 mov     ecx, [ebp-98h]
.text:7F00FE84                 cmp     ecx, [ebp-88h]           ;cmp total
"PointtStruct" number
.text:7F00FE8A                 jb      short loc_7F00FE4F       ;traverse
all "PointtStruct"
.text:7F00FE8C
.text:7F00FE8C loc_7F00FE8C:                                    ; CODE XREF:
PlayMetaFileRecord+C46j
.text:7F00FE8C                                                  ;
PlayMetaFileRecord+14D8j
.text:7F00FE8C                 cmp     dword ptr [ebp-94h], 0
.text:7F00FE93                 jnz     loc_7F022BA2
.text:7F00FE99                 cmp     edi, 0FFFFFFDh
.text:7F00FE9F                 jnb     loc_7F022BA2
.text:7F00FEA5                 mov     eax, [ebp-8Ch]
.text:7F00FEAB                 add     eax, 2
.text:7F00FEAE                 shl     eax, 4
.text:7F00FEB1                 mov     [ebp-9Ch], eax
.text:7F00FEB7                 push    eax             ; uBytes
.text:7F00FEB8                 push    0               ; uFlags
.text:7F00FEBA                 call    ds:LocalAlloc            ;will
allocate memory normally.
.text:7F00FEC0                 mov     edi, eax

so when we set "Parameters.All_PointtStruct_Num","PointtStruct.PointNum" big
enough,but not many enough "PointtStruct" structure,will trigger a memory
access error on 7F00FE4F.


2.ExtEscape POSTSCRIPT_INJECTION result in memory overrun vulnerability int
ExtEscape(
  hdc,                  // handle to DC (HDC)
  POSTSCRIPT_INJECTION, // nEscape param of ExtEscape
  cbInput,              // size of input buffer
  lpszInData,           // pointer to input (PSINJECTDATA *)
  0,                    // cbOutput param of ExtEscape
  NULL                  // lpszOutData param of ExtEscape
);

we can control cbInput and szInData,so when we set cbInput big enough(like
0xffff),but set szInData very small,will trigger a memory access
error(7F027358) likely.

.text:7F027312 loc_7F027312:                           ; CODE XREF:
ExtEscape+11Ej
.text:7F027312                                         ; ExtEscape+12Aj
.text:7F027312                 test    byte ptr [ecx+4], 40h
.text:7F027316                 jnz     loc_7F017CEC
.text:7F02731C                 mov     ebx, [ebp+arg_8]         ;we can
cotrol this:cbSize
.text:7F02731F                 add     ebx, 1Ah                 ;cbSize+0x1a
.text:7F027322                 and     ebx, 0FFFFFFFCh
;cbSize+0x1a-4
.text:7F027325                 mov     eax, large fs:18h
.text:7F02732B                 mov     eax, [eax+30h]
.text:7F02732E                 push    ebx
.text:7F02732F                 push    0
.text:7F027331                 push    dword ptr [eax+18h]
.text:7F027334                 call    ds:RtlAllocateHeap       ;allocate
memory size=cbSize+0x16
.text:7F02733A                 test    eax, eax
.text:7F02733C                 jz      short loc_7F027385
.text:7F02733E                 mov     ecx, [ebp+arg_4]
.text:7F027341                 mov     [eax+0Ch], ecx
.text:7F027344                 mov     ecx, [ebp+arg_8]
.text:7F027347                 mov     [eax+10h], ecx
.text:7F02734A                 mov     edx, ecx
.text:7F02734C                 shr     ecx, 2
.text:7F02734F                 sub     ebx, 8
.text:7F027352                 mov     [eax+8], ebx
.text:7F027355                 lea     edi, [eax+14h]
.text:7F027358                 rep movsd                        ;copy,here
will trigger a memory error likely**
.text:7F02735A                 mov     ecx, edx
.text:7F02735C                 and     ecx, 3
.text:7F02735F                 rep movsb
.text:7F027361                 mov     ecx, [ebp-4]
.text:7F027364                 mov     edi, [ebp+arg_14]
.text:7F027367                 lea     edx, [ecx+48h]
.text:7F02736A                 mov     esi, [edx+4]
.text:7F02736D                 mov     [eax+4], esi

Exploit:
first vul can test like this:
  ...05020000FF0044444444444444444444FFFF33333333333333333333FFFF41424344...
second vul can test like this:
  ...0502000026001610FFFF4444444444444444...
my blog can not be opened now:p,i will upload the exploit files to
xfocus(www.xfocus.net) later,have fun:)

Solution:
Microsoft has not develop the patch,please unregister the Windows Picture
and Fax Viewer (Shimgvw.dll)(see MS06-001).

Thanks:
thanks all my friends,Happy Weekday:)

-EOF-

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