为了实现自动刷SRC的目标,过年前就开始对w13scan的xss扫描功能进行优化,灵感注入xray所引起的基于语义的扫描技术。
xss扫描之前是w3af
xss payload,通常在以下几个部分。
后面我认真的学习了一下Xsstrike
,Xray
,Awvs
中的检测技巧以及检测参数,想将它们的优点和为一体。
先说说Xsstrike
,里面带有xss扫描和fuzz,但感觉xss扫描的效果也不是太理想。不过它的一些特性还是可以学习的。
Xsstrike的dom扫描,是通过正则来分析敏感函数
sources = r'''document\.(URL|documentURI|URLUnencoded|baseURI|cookie|referrer)|location\.(href|search|hash|pathname)|window\.name|history\.(pushState|replaceState)(local|session)Storage'''
sinks = r'''eval|evaluate|execCommand|assign|navigate|getResponseHeaderopen|showModalDialog|Function|set(Timeout|Interval|Immediate)|execScript|crypto.generateCRMFRequest|ScriptElement\.(src|text|textContent|innerText)|.*?\.onEventName|document\.(write|writeln)|.*?\.innerHTML|Range\.createContextualFragment|(document|window)\.location'''
scripts = re.findall(r'(?i)(?s)<script[^>]*>(.*?)</script>', response)
通过将script脚本内的内容提取出来,通过一些正则来获取,最后输出。但这种方式准确度很低,只能用于辅助,不太适合自动化扫描。
它里面有内置一些参数,在检测时转化这些参数也一起发送
blindParams = [ # common paramtere names to be bruteforced for parameter discovery
'redirect', 'redir', 'url', 'link', 'goto', 'debug', '_debug', 'test', 'get', 'index', 'src', 'source', 'file',
'frame', 'config', 'new', 'old', 'var', 'rurl', 'return_to', '_return', 'returl', 'last', 'text', 'load', 'email',
'mail', 'user', 'username', 'password', 'pass', 'passwd', 'first_name', 'last_name', 'back', 'href', 'ref', 'data', 'input',
'out', 'net', 'host', 'address', 'code', 'auth', 'userid', 'auth_token', 'token', 'error', 'keyword', 'key', 'q', 'query', 'aid',
'bid', 'cid', 'did', 'eid', 'fid', 'gid', 'hid', 'iid', 'jid', 'kid', 'lid', 'mid', 'nid', 'oid', 'pid', 'qid', 'rid', 'sid',
'tid', 'uid', 'vid', 'wid', 'xid', 'yid', 'zid', 'cal', 'country', 'x', 'y', 'topic', 'title', 'head', 'higher', 'lower', 'width',
'height', 'add', 'result', 'log', 'demo', 'example', 'message']
很好的思路,后面我的扫描器中也使用了这一点,从乌云镜像XSS分类中提取出了top10参数,在扫描时也会将这些参数加上。
如果参数可以回显,那么通过html解析就可以获得参数位置,分析回显的环境(是否在html标签内,是否在html属性内,是否在注释中,是否在js中)等等,否则来确定检测的payload。
后面我的扫描器的检测流程也是这样,非常准确和效率,不过Xsstrike
分析html是自己写的分析函数,刚开始我也想直接用它的来着,但是这个函数内容过多,调试困难,代码也很难理解。
其实如果把html解析理解为html的语义分析,用python3自带的html提取函数很容易就能完成这一点。
XSStrike
让我学习到了新一代xss扫描器应该如何编写,但新一代xss扫描器的payload是在Xray
上学到的。
由于Xray
没有开源,所以就通过分析日志的方式来看它的工作原理。
<html>
<body>
<a href="?q=1&w=2&e=3&r=4&t=5" />
<script>
<php
foreach($_GET as $key => $value){
// $_GET[$key] = htmlspecialchars($value);
}
$q = $_GET["q"];
$w = $_GET["w"];
$e = $_GET["e"];
$r = $_GET["r"];
$t = $_GET["t"];
if(stripos($q,"prompt") > 0){
die("error");
}
$var = 'var a = "'.$q.'";';
echo $var;
>
</script>
<div>
<textarea><?php echo $w;?></textarea>
</div>
<input style="color:<?php echo $e;?>" value="<?php echo $r;?>"/>
<!--
this is comment
<?php echo $t;?>
-->
</body>
</html>
简单写了一个脚本,用来分别测试xss在script,style内,html标签内,注释这几种情况下xray的发包过程。
1.对于在script的脚本内的回显内容,对于以下case
<script>
$var = 'var a = "'.$_GET['q'].'";';
echo $var;
</script>
X射线顺序发送了以下payload:pdrjzsqc
,"-pdrjzsqc-"
,</sCrIpT><ojyrqvrzar>
最后会给出payload,但这个包并没有发送。后面把prompt
作为关键词屏蔽,发现最后还是给出这个payload。
还有一种情况,在script中的注释中输出
<html>
<body>
<script>
var a = 11;
// inline <?php echo $_GET["a"];?>
/* <?php echo $_GET["b"];?> */
</script>
</body>
</html>
xray会发送`\n;chxdsdkm;//`来判定,最后给出payload `\n;prompt(1);//`
2.对于在标签内的内容,针对以下case
<textarea><?php echo $_GET["w"];?></textarea>
xray顺序发送了以下payload:spzzmsntfzikatuchsvu
,</tExTaReA><lixoorqfwj>
,当确定尖括号没有被过滤时,会继续发送以下payload:</TeXtArEa>sCrIpTjhymehqbkrScRiPt
,</TeXtArEa>iMgSrCoNeRrOrjhymehqbkr>
,</TeXtArEa>SvGoNlOaDjhymehqbkr>
,</TeXtArEa>IfRaMeSrCjAvAsCrIpTjhymehqbkr>
,</TeXtArEa>aHrEfJaVaScRiPtjhymehqbkrClIcKa
,</TeXtArEa>iNpUtAuToFoCuSoNfOcUsjhymehqbkr>
,进行关键词的试探,最后给出payload为</TeXtArEa><img src=1>
3.对于在style里内容,以下case
<input style="color:<?php echo
xray顺序发送了以下payload:kmbrocvz
,expression(a(kmbrocvz))
4.对于在html标签内的内容,以下case
<input style="color:3" value="<?php echo $_GET["r"];?>"/>
xray顺序发送了以下payload:spzzmsntfzikatuchsvu
,"ljxxrwom="
,'ljxxrwom='
,ljxxrwom=
,当确认引号没有被过滤时,会继续发送以下payload:"><vkvjfzrtgi>
,">ScRiPtvkvjfzrtgiScRiPt
,">ImGsRcOnErRoRvkvjfzrtgi>
,">SvGoNlOaDvkvjfzrtgi>
,">iFrAmEsRcJaVaScRiPtvkvjfzrtgi>
,">aHrEfJaVaScRiPtvkvjfzrtgicLiCkA
,">InPuTaUtOfOcUsOnFoCuSvkvjfzrtgi>
," OnMoUsEoVeR=xviinqws
,最后可以确定payload为"><img src=1>
,"OnMoUsEoVeR=prompt(1)//
如果针对此类case:
<img src=1 onerror="a<?php echo htmlspecialchars($_GET["a"]);?>" />
xray返回payload为prompt(1)
,说明xray会把onerror
后面的内容当作JavaScript脚本来执行,如果把onerror
改为onerror1
,同样会返回prompt
。在awvs规则中也看到过类似的规则
parName == "ONAFTERPRINT" ||
parName == "ONBEFOREPRINT" ||
parName == "ONBEFOREONLOAD" ||
parName == "ONBLUR" ||
parName == "ONERROR" ||
parName == "ONFOCUS" ||
parName == "ONHASCHANGE" ||
parName == "ONLOAD" ||
parName == "ONMESSAGE" ||
parName == "ONOFFLINE" ||
parName == "ONONLINE" ||
parName == "ONPAGEHIDE" ||
parName == "ONPAGESHOW" ||
parName == "ONPOPSTATE" ||
parName == "ONREDO" ||
parName == "ONRESIZE" ||
parName == "ONSTORAGE" ||
parName == "ONUNDO" ||
parName == "ONUNLOAD" ||
parName == "ONBLUR" ||
parName == "ONCHANGE" ||
parName == "ONCONTEXTMENU" ||
parName == "ONFOCUS" ||
parName == "ONFORMCHANGE" ||
parName == "ONFORMINPUT" ||
parName == "ONINPUT" ||
parName == "ONINVALID" ||
parName == "ONRESET" ||
parName == "ONSELECT" ||
parName == "ONSUBMIT" ||
parName == "ONKEYDOWN" ||
parName == "ONKEYPRESS" ||
parName == "ONKEYUP" ||
parName == "ONCLICK" ||
parName == "ONDBLCLICK" ||
parName == "ONDRAG" ||
parName == "ONDRAGEND" ||
parName == "ONDRAGENTER" ||
parName == "ONDRAGLEAVE" ||
parName == "ONDRAGOVER" ||
parName == "ONDRAGSTART" ||
parName == "ONDROP" ||
parName == "ONMOUSEDOWN" ||
parName == "ONMOUSEMOVE" ||
parName == "ONMOUSEOUT" ||
parName == "ONMOUSEOVER" ||
parName == "ONMOUSEUP" ||
parName == "ONMOUSEWHEEL" ||
parName == "ONSCROLL" ||
parName == "ONABORT" ||
parName == "ONCANPLAY" ||
parName == "ONCANPLAYTHROUGH" ||
parName == "ONDURATIONCHANGE" ||
parName == "ONEMPTIED" ||
parName == "ONENDED" ||
parName == "ONERROR" ||
parName == "ONLOADEDDATA" ||
parName == "ONLOADEDMETADATA" ||
parName == "ONLOADSTART" ||
parName == "ONPAUSE" ||
parName == "ONPLAY" ||
parName == "ONPLAYING" ||
parName == "ONPROGRESS" ||
parName == "ONRATECHANGE" ||
parName == "ONREADYSTATECHANGE" ||
parName == "ONSEEKED" ||
parName == "ONSEEKING" ||
parName == "ONSTALLED" ||
parName == "ONSUSPEND" ||
parName == "ONTIMEUPDATE" ||
parName == "ONVOLUMECHANGE" ||
parName == "ONWAITING" ||
parName == "ONTOUCHSTART" ||
parName == "ONTOUCHMOVE" ||
parName == "ONTOUCHEND" ||
parName == "ONTOUCHENTER" ||
parName == "ONTOUCHLEAVE" ||
parName == "ONTOUCHCANCEL" ||
parName == "ONGESTURESTART" ||
parName == "ONGESTURECHANGE" ||
parName == "ONGESTUREEND" ||
parName == "ONPOINTERDOWN" ||
parName == "ONPOINTERUP" ||
parName == "ONPOINTERCANCEL" ||
parName == "ONPOINTERMOVE" ||
parName == "ONPOINTEROVER" ||
parName == "ONPOINTEROUT" ||
parName == "ONPOINTERENTER" ||
parName == "ONPOINTERLEAVE" ||
parName == "ONGOTPOINTERCAPTURE" ||
parName == "ONLOSTPOINTERCAPTURE" ||
parName == "ONCUT" ||
parName == "ONCOPY" ||
parName == "ONPASTE" ||
parName == "ONBEFORECUT" ||
parName == "ONBEFORECOPY" ||
parName == "ONBEFOREPASTE" ||
parName == "ONAFTERUPDATE" ||
parName == "ONBEFOREUPDATE" ||
parName == "ONCELLCHANGE" ||
parName == "ONDATAAVAILABLE" ||
parName == "ONDATASETCHANGED" ||
parName == "ONDATASETCOMPLETE" ||
parName == "ONERRORUPDATE" ||
parName == "ONROWENTER" ||
parName == "ONROWEXIT" ||
parName == "ONROWSDELETE" ||
parName == "ONROWINSERTED" ||
parName == "ONCONTEXTMENU" ||
parName == "ONDRAG" ||
parName == "ONDRAGSTART" ||
parName == "ONDRAGENTER" ||
parName == "ONDRAGOVER" ||
parName == "ONDRAGLEAVE" ||
parName == "ONDRAGEND" ||
parName == "ONDROP" ||
parName == "ONSELECTSTART" ||
parName == "ONHELP" ||
parName == "ONBEFOREUNLOAD" ||
parName == "ONSTOP" ||
parName == "ONBEFOREEDITFOCUS" ||
parName == "ONSTART" ||
parName == "ONFINISH" ||
parName == "ONBOUNCE" ||
parName == "ONBEFOREPRINT" ||
parName == "ONAFTERPRINT" ||
parName == "ONPROPERTYCHANGE" ||
parName == "ONFILTERCHANGE" ||
parName == "ONREADYSTATECHANGE" ||
parName == "ONLOSECAPTURE" ||
parName == "ONDRAGDROP" ||
parName == "ONDRAGENTER" ||
parName == "ONDRAGEXIT" ||
parName == "ONDRAGGESTURE" ||
parName == "ONDRAGOVER" ||
parName == "ONCLOSE" ||
parName == "ONCOMMAND" ||
parName == "ONINPUT" ||
parName == "ONCONTEXTMENU" ||
parName == "ONOVERFLOW" ||
parName == "ONOVERFLOWCHANGED" ||
parName == "ONUNDERFLOW" ||
parName == "ONPOPUPHIDDEN" ||
parName == "ONPOPUPHIDING" ||
parName == "ONPOPUPSHOWING" ||
parName == "ONPOPUPSHOWN" ||
parName == "ONBROADCAST" ||
parName == "ONCOMMANDUPDATE" ||
parName == "STYLE"
awvs会比较参数名称来确定。在后面的自动化扫描中,发现这种方式的误报还是很高,最后我将这种情况调整到了awvs的方式,只检测指定的属性key。
从这两处细微的差异可以看到,awvs宁愿漏报也不误报,结果会很准确,xray更多针对白帽子,结果会宽泛一些。
5.对于在html注释内的内容,以下case
<!--
this is comment
<?php echo $t;?>
-->
xray顺序发送了以下payload:spzzmsntfzikatuchsvu
,--><husyfmzvuq>
,--!><oamtgwmoiz>
,和上面类似,当确定-->
或--!>
没有过滤时,会发送
以 --> 或 --!> 开头,添加如下内容
<bvwpmjtngz>
sCrIpTbvwpmjtngzsCrIpT
ImGsRcOnErRoRbvwpmjtngz>
sVgOnLoAdbvwpmjtngz>
iFrAmEsRcJaVaScRiPtbvwpmjtngz>
aHrEfJaVaScRiPtbvwpmjtngzcLiCkA
InPuTaUtOfOcUsOnFoCuSbvwpmjtngz>
Awvs的扫描规则很多,针对的情况也很多,没有仔细看它的工作方式是怎样的,主要是看它的payload以及检测的情况,和上面两种查漏补缺,最终合成了我的xss扫描器~比如它会对meta标签的content内容进行处理,会对你srcipt,src等tag的属性处理,也有一些对AngularJs等一些流行的框架的XSS探测payload。。
我的XSS扫描器就是综合上面的几种扫描器而来,如果仔细观察,将会发现上面的扫描器的一些不同寻常的细节。
比如xray不会发送xss的payload,都是用一些随机字符来代替,同时也会随机大小写对一些标签名称,属性名称等等。
这些精致的技巧我的扫描器也都一一吸取了,嘿嘿!
我的扫描器扫描流程是这样的
发送随机flag -> 确定参数回显 -> 确定回显位置以及情况(html,js语法解析) -> 根据情况根据不同payload探测 -> 使用html,js语法解析确定是否多出来了标签,属性,js语句等等
使用html语法树检测有很多优势,可以准确判定回显所处的位置,然后通过发送一个随机payload,例如<Asfaa>
,再使用语法检测是否有Asfaa
这个标签,就能确定payload是否执行成功了。
html语法树用python自带的库
from html.parser import HTMLParser
js检测也是如此,如果回显内容在JavaScript脚本中,发送随机flag后,通过js语法解析只需要确定Identifier
和Literal
这两个类型中是否包含,如果flag是Identifier类型,就能直接判断存在xss,payload是alert(1)//
,如果flag是Literal
类型,再通过单双引号来闭合进行检测。
整个xss扫描代码不过1000行,但debug的过程是道阻且长。
本地靶机测试后就对在线的靶机进行了测试 https://brutelogic.com.br/knoxss.html
查漏补缺后就就开始了自动化扫描。
整个自动化架构如下
1\. 提供url -> 爬虫爬取 -> 参数入库 -> 消息队列 -> xss扫描器
-> 子域名入库
-> url入库
1.爬虫使用的crawlergo,效果挺不错的,但还是不太满足我的需求(造轮子的心态又膨胀了)
2.数据库使用的mongodb
3.用celery分散调用,由于用到了celery,又用到了rabbitmq消息编码,鲜花监控
4.用了服务器酱进行微信推送(得到一个扩展微信就会响一次)
刚开始打把游戏微信就会不停的响,然后就查找误报,优化逻辑,随之而来
经过了不懈的改造,优化了检测逻辑,加入了去重处理后,现在既扫描的慢且推动的消息也变少了。
经过缩短对src的扫描后,成功还是挺多的(很多都归功于爬虫)
甚至发现了微软分站某处xss
未完,待续。。。
*本文作者:w7ay @知道创宇404实验室,转载请注明来自FreeBuf.COM