本文主要分享一款静态的IE浏览器模糊测试工具，该工具被称为IEFuzz。我们知道，像其他大部分软件一样，浏览器也往往通过两种方式进行模糊测试，一种为静态，另外一种则为动态。
在此前，我们在其他文章中也了解过其他的Fuzzer，如X-Fuzzer，PKAV HTTP Fuzzer，也了解过相关的Fuzzing方法,如从零开始学Fuzzing系列：浏览器挖掘框架Morph诞生记等。本文主要讲述静态浏览器Fuzzer的情况。
在当下，动态浏览器Fuzzer占据着主流，因为它们的运行效率高(纯粹是用JavaScript写的)。然而，当我们在进行动态Fuzzing 的时候，往往面临着一个共同的问题，就是“异常事件重现”。所以一般我们在构建JS 浏览器 Fuzzer时都需要非常仔细，否则在运行过程中可能会由于浏览器Fuzzer是动态的，将导致异常事件不可重现。
所以，在Fuzzing之前，我们往往需要考虑以下几个方面的问题：
1、测试实例(样本)如何生成? 2、对异常事件如何监控? 3、对于引起异常事件的测试实例如何保存? 4、异常事件如何重现?
对于上述使用动态 Fuzzer面临的问题，另外一种解决思路是，采用静态Fuzzer进行检测。虽然静态Fuzzer效率较低，但是一般都可以重现异常事件的。
IEFuzz简介
该静态IE fuzzer 是用python编写的，包括使用到以下模块:
pywin32com ——用于加载或者重载*.html测试实例;
pydbg——用于监控IE浏览器的异常事件;
paimei——用于生成异常事件的dump文件，下载链接为：paimei。
IEFuzz使用配置
为了能够顺利进行Fuzzing,我们需要在IE设置中做如下更改。
1、首先，因为Fuzzer 需要在本地加载测试实例(如加载路径为file://c:/fuzzer/testcases/temp.html)所以应该先将IE的ActiveX告警提示关闭，通过如下步骤：
(1)工具->Internet 选项->安全->自定义级别;
(2)随后将ActiveX告警提示关闭。
2、接着，为了能够使用 Python win32com来监控IE，我们还需要关闭IE的保护模块。但是请注意其中的风险。
(1)工具->Internet 选项->安全->受信任的站点：自定义级别为低;
(2)工具->Internet 选项->安全->Internet:自定义级别为中，同时关闭保护模式;
(3)工具->Internet 选项->安全->受限站点：关闭保护模式。
编写测试实例
首先我们可以基于该fuzzer编写自己的静态测试用例生成器。之后可以将其放在/TestCases文件夹中。在GitHub源码中， 也提供了一个样本以供参考：’TestCases/SampleTestCase.py。因源码篇幅较长，链接如下，
在编写测试实例时也请注意，实例中需要包含一个TestCase类以及getFinalTestCase()方法。 getFinalTestCase()方法需要能够返回完整的 Html页面。
在动态fuzzer的应用过程中，需要从对象中提取不同的Html元素属性，然后在运行状态下进行模糊检测。而对于一个静态Fuzzer，我们能够在我们的python测试实例中预定义html元素以及属性，并将之作为字典dict。
dict举例如下：
- attr = {'CANVAS':['height','width','getContext', ... , ... , ... ]}
对于这种属性生成列表，也提供了一个JavaScript 应用供参考。
- <html>
- <head>
- <script>
- /*
- ----------------------------------------------------------------------------
- "THE BEER-WARE LICENSE" (Revision 42):
- <debasishm89_at_gmail.com> wrote this file. As long as you retain this notice you
- can do whatever you want with this stuff. If we meet some day, and you think
- this stuff is worth it, you can buy me a beer in return. Debasish Mandal
- ----------------------------------------------------------------------------
- This JS code should be used for generating a python dict. of element attributes of different HTML elements.
- In case of dynamic fuzzer, its usually generated on the fly, since its a static fuzzer you need to pre define html elements and their attributes to your test case.
- Other wise you can use a list of well known attributes. It's completely your choice, how you write your test case.
- */
- function getEleAttributes(ele){
- buff = "['"
- for( var p in ele ){
- buff += p + "','";
- }
- buff = buff.slice(0, -2) + "]";
- return buff
- }
- function generate() {
- /*
- Add your element list in this here and open this html in IE.
- */
- var elements = ["ARTICLE","ASISE","B","BDI","BDO", "BLOCKQUOTE","BR","BUTTON","CANVAS","CAPTION","CITE","COL","CODE","COMMAND","DATALIST","DD","DEL","DETAILS","DFN","DL","DT", "EM","STYLE","FIELDSET","FIGCAPTION","SCRIPT", "EMBED","FIGURE","FOOTER","HEADER","HGROUP","HR","I","INPUT","INS","KEYGEN","KBD","LEGEND","MARK","MENU","METER","NAV","NOSCRIPT","OPTGROUP","OUTPUT","P","PARAM","PRE","PROGRESS","Q","RP","RT","RUBY","S","SAMP","SECTION","SELECT","SMALL","SOURCE","SPAN","SUP","TH","THEAD","TIME","OBJECT","IFRAME","TEXTAREA","TRACK","U","VAR","WBR","FORM","A","BODY","HTML","DIV","TABLE","AREA","TD","TR","LINK","BASE","FONT","HEAD","IMG","MAP","META","OL","LI","TBODY","TITLE","H1","BLINK","AREA","COL","SPAN","FRAMESET","FRAME","UL","OPTION","NOFRAMES","TFOOT","XMP","ISINDEX","CENTER","HR","LABEL","OPTGROUP","AUDIO","VIDEO","TEMPLATE","SVG"]
- main_buff = "ele_dict = {"
- for (ele in elements){
- var id_0 = document.createElement( elements[ele] );
- all_props = getEleAttributes(id_0)
- main_buff += "'"+elements[ele]
- main_buff += "':"
- main_buff += all_props
- main_buff += ","
- }
- main_buff = main_buff.slice(0,-1)
- main_buff += "}"
- document.getElementById('result').innerHTML = main_buff;
- }
- </script>
- </head>
- <body onload='generate();'>
- <b>Output : (Copy paste following python dictionary to your testcase generator script and fuzz using them )</b></br><textarea id="result" rows="100" cols="200"></textarea>
- </body>
- </html>
参考链接为：Generate_Elements_Dict.html
IEFuzz运行步骤
那么IEFuzz 是如何运行的?请参考往下步骤:
1、启动IE; 2、将iexplore.exe进程挂载到 Debugger(pydbg) 中，然后对其父进程以及子进程所有类型的事件进行监控; 3、生成一个静态实例(Html + JavaScript); 4、通过win32COM加载该静态实例到本地(如file://c:/fuzzer/testcases/temp.html) 5、如果没有产生异常事件，那么就需要重新生成一个Html测试实例，然后再使用win32COM (python模块)进行重载。(在这里先不关闭IE或者重新打开IE。可以说，我们只是重新刷新了页面，但是页面的代码或者内容是不同的，这也给测试节省了时间); 6、在出现异常事件时，先复制或者保存测试实例到一个单独的文件夹，然后再关闭IE进程; 7、返回步骤1。
