Java安全之Resin2内存马 _生活百科

Java安全之Resin2内存马环境resin2.1.17
添加Filter分析依然是web.xml注册一个filter，debug进去看注册流程
debug dofilter逻辑时看到如下代码，最终走入this._filterChain = this._application.buildFilterChain(this, this._config);去build filterchain 。并且貌似是初始化的时候才会去buildfilterchain，当后面第二次再走时，这里的_filterchain已经是有值的了。

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this._application应为上下文对象，继续往下跟通过QFilterConfig#createFilter来创建了一个Filter，之后new 了一个FilterChain

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注意下面三个对象，添加上即可

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_filterMap首先看FilterMap构造，主要是Regexp，QFilterConfig后面再说

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可以反射实例化之后调用方法或者set属性来设置值

class FilterMap {static L10N L;private String servletName;private Regexp regexp;private Object data;FilterMap() {}void setServletName(String servletName) {this.servletName = servletName;}void setRegexp(String regexpPattern, String flags) throws Exception {this.regexp = new Regexp(regexpPattern, flags);}void setURLPattern(String urlPattern, String flags) throws ServletException {this.regexp = this.urlPatternToRegexp(urlPattern, flags);}

下面看Regexp ,其实就是一个正则来控制的路由处理
^.*$^(?=/)|^$调用有参构造即可

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_filtershashtable对象，key为filtername，value为QFilterConfig对象，key可以随便伪造成个正常的

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_filterList直接add一个QFilterConfig元素即可

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看到QConfigFilter，Registry为空就走if的逻辑，传入构造好的属性即可

package com.caucho.server.http;import com.caucho.util.BeanUtil;import com.caucho.util.CauchoSystem;import com.caucho.util.L10N;import com.caucho.util.RegistryNode;import java.util.Collections;import java.util.Enumeration;import java.util.HashMap;import java.util.Iterator;import javax.servlet.Filter;import javax.servlet.FilterConfig;import javax.servlet.ServletContext;import javax.servlet.ServletException;class QFilterConfig implements FilterConfig {static L10N L;private static HashMap _configElements;private Application _application;private RegistryNode _registry;private RegistryNode _initRegistry;private String _name;private String _className;private HashMap _init;private Filter _filter;QFilterConfig(Application application, String name, String defaultClassName, RegistryNode registry) throws ServletException {this._application = application;this._registry = registry;this._name = name;this._init = new HashMap();if (registry == null) {if (defaultClassName == null) {this._className = name;} else {this._className = defaultClassName;}} else {this._className = registry.getString("filter-class", defaultClassName);Iterator iter = registry.iterator();while(iter.hasNext()) {RegistryNode node = (RegistryNode)iter.next();if (node.getName().equals("init-param")) {try {application.fillParam(node, this._init);} catch (ServletException var8) {throw var8;} catch (Exception var9) {throw new ServletException(var9);}} else if (node.getName().equals("init")) {this._initRegistry = node;} else if (_configElements.get(node.getName()) == null) {throw Application.error(node, L.l("unknown element `{0}' in {1}", node.getName(), registry.getName()));}}}}

后面就是用c0ny1师傅的java-object-searcher工具挖掘Application和Request在当前线程上下文的位置即可。