CG-CTF | 综合题2

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查源码发现一个文件读取:http://cms.nuptzj.cn/about.php?file=sm.txt,用它把能找到的php都读取下来

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<?php 
    if (!isset($_COOKIE[‘username‘])) 
    {
        setcookie(‘username‘, ‘‘);
        setcookie(‘userpass‘, ‘‘);
    }
?>
  <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
  <html xmlns="http://www.w3.org/1999/xhtml">
    
    <head>
      <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
      <title>皇家邮电渗透测试平台</title>
      <style type="text/css">
        <!-- .STYLE1 {font-size: 18px} --></style>
    </head>
    
    <body>
      <center>
        <h1>Xlcteam客户留言板</h1>
        <p>
          <hr />&nbsp;</p>
        <div align="left" style="width:1024px">
          <h3>&nbsp;&nbsp;欢迎来到Xlcteam客户留言板,各位朋友可以在这里留下对本公司的意见或建议。
            <br />
            <br />&nbsp;&nbsp;本组织主要为企业提供网络安全服务。正如公司名所说,本公司是混迹在“娱乐圈”中的公司,喜欢装B,一直摸黑竞争对手,从未被黑。
            <br />&nbsp;&nbsp;本公司的经营理念为“技术好,算个吊,摸黑对手有一套,坑到学生才叫吊~”。
            <br />&nbsp;&nbsp;你别说不爽我们,有本事来爆我们(科哥)菊花~ come on!!</h3>&nbsp;</div>
        <hr />
        <div id="msg" name="msg" align="left" style="width:1024px">
          <h2>客户留言:</h2>
          <hr />
          <br />
          <?php //这里输出用户留言 
           include ‘antixss.php‘; 
          include ‘config.php‘; 
          $con=m ysql_connect($db_address,$db_user,$db_pass) or die( "不能连接到数据库!!".mysql_error()); 
          mysql_select_db($db_name,$con); 
          $page=$_GET[ ‘page‘]; 
          if($page=="" || $page==0)
          { 
            $page=‘1‘ ; } 
            $page=intval($page); $start=($page-1)*7; 
            $last=$page*7; 
            $result=mysql_query( "SELECT * FROM `message` WHERE display=1 ORDER BY id LIMIT $start,$last"); 
            if(mysql_num_rows($result)>0)
            { 
                while($rs=mysql_fetch_array($result))
                { 
                    echo htmlspecialchars($rs[‘nice‘],ENT_QUOTES).":<br />"; echo ‘&nbsp;&nbsp;&nbsp;&nbsp;‘.antixss($rs[‘say‘]).‘<br /><hr />‘; 
                } 
            }
            mysql_free_result($result);
          ?>
            <center>
              <p>
                <a href="index.php">首页</a>
                <?php 
                    $contents = mysql_query("SELECT * FROM `message` WHERE display=1");
                    if (mysql_num_rows($contents) > 0) 
                    {
                        $num = mysql_num_rows($contents);
                        if ($num % 8 != 0) 
                        {
                            $pagenum = intval($num / 8) + 1;
                        } 
                        else 
                        {
                            $pagenum = intval($num / 8);
                        }
                        for ($i = 1;$i <= $pagenum;$i++) 
                        {
                            echo ‘<a href="index.php?page=‘ . htmlspecialchars($i) . ‘">‘ . htmlspecialchars($i) . ‘</a>&nbsp;‘;
                        }
                    }
                    mysql_free_result($contents);
                    mysql_close($con); 
                ?>
                    <a href="index.php?page=<?php echo htmlspecialchars($pagenum);?>">尾页</a></p>
              <form method="post" action="./so.php">留言搜索(输入ID):
                <input name="soid" type="text" id="soid" />
                <input type="submit" value="搜索" /></form></center>
        </div>
        <hr />
        <div id="say" name="say" align="left" style="width:1024px">
          <h2>留言:</h2>
          <form method="post" action="./preview.php">
            <span class="STYLE1">昵称:</span>
            <input name="nice" type="text" id="nice" 
            <?php //这里是获取昵称的cookie再显示
            value = ""$username = $_COOKIE[‘username‘];
            $username = htmlspecialchars($username, ENT_QUOTES);
            echo ‘ value="‘ . $username . ‘" ‘; 
            ?>/></label>
            <p class="STYLE1">内容:
              <br />&nbsp;&nbsp;&nbsp;
              <textarea style="width:800px;height:100px" name="usersay" id="usersay"></textarea>
              <label>
                <br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
                <input onclick="return checkform()" type="submit" name="Submit" style="width:600px;height:50px" value="预览" /></label>
              <br />&nbsp;&nbsp;&nbsp;&nbsp;(可用[a]网址[/a]代替&lt;a href=&quot;网址&quot; &gt;网址&lt;/a&gt;)</p></form>
        </div>
        <div>
          <h4>
            <a href="./about.php?file=sm.txt">本CMS说明</a></h4>
        </div>
        <div align="center">鸣谢·红客联盟(HUC)官网
          <br /></div></center>
      <script>function checkform() {
          if (say.nice.value == "" || say.usersay.value == "") {
            alert("昵称或留言内容不能为空");
            return false;
          } else {
            return true;
          }</script>
    </body>
  
  </html>
index.php
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<?php function passencode($content) { 
    //$pass = urlencode($content);
    $array = str_split($content);
    $pass = "";
    for ($i = 0;$i < count($array);$i++) {
        if ($pass != "") {
            $pass = $pass . " " . (string)ord($array[$i]);
        } else {
            $pass = (string)ord($array[$i]);
        }
    }
    return $pass;
} ?>
passencode.php
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<?php
    include ‘config.php‘;
    $nice = $_POST[‘nice‘];
    $say = $_POST[‘usersay‘];
    if (!isset($_COOKIE[‘username‘])) 
    {
        setcookie(‘username‘, $nice);
        setcookie(‘userpass‘, ‘‘);
    }
    $username = $_COOKIE[‘username‘];
    $userpass = $_COOKIE[‘userpass‘];
    if ($nice == "" || $say == "") 
    {
        echo "<script>alert(‘昵称或留言内容不能为空!(如果有内容也弹出此框,不是网站问题喔~ 好吧,给个提示:查看页面源码有惊喜!)‘);</script>";
        exit();
    }
    $con = mysql_connect($db_address, $db_user, $db_pass) or die("不能连接到数据库!!" . mysql_error());
    mysql_select_db($db_name, $con);
    $nice = mysql_real_escape_string($nice);
    $username = mysql_real_escape_string($username);
    $userpass = mysql_real_escape_string($userpass);
    $result = mysql_query("SELECT username FROM admin where username=‘$nice‘", $con);
    $login = mysql_query("SELECT * FROM admin where username=‘$username‘ AND userpass=‘$userpass‘", $con);
    if (mysql_num_rows($result) > 0 && mysql_num_rows($login) <= 0) {
        echo "<script>alert(‘昵称已被使用,请更换!‘);</script>";
        mysql_free_result($login);
        mysql_free_result($result);
        mysql_close($con);
        exit();
    }
    mysql_free_result($login);
    mysql_free_result($result);
    $say = mysql_real_escape_string($say);
    mysql_query("insert into message (nice,say,display) values(‘$nice‘,‘$say‘,0)", $con);
    mysql_close($con);
    echo ‘<script>alert("构建和谐社会,留言需要经过管理员审核才可以显示!");window.location = "./index.php"</script>‘;
?>gt;
say.php
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
  
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title>搜索留言</title></head>
  
  <body>
    <center>
      <div id="say" name="say" align="left" style="width:1024px">
        <?php 
            if ($_SERVER[‘HTTP_USER_AGENT‘] != "Xlcteam Browser") 
            {
                echo ‘万恶滴黑阔,本功能只有用本公司开发的浏览器才可以用喔~‘;
                exit();
            }
            $id = $_POST[‘soid‘];
            include ‘config.php‘;
            include ‘antiinject.php‘;
            include ‘antixss.php‘;
            $id = antiinject($id);
            $con = mysql_connect($db_address, $db_user, $db_pass) or die("不能连接到数据库!!" . mysql_error());
            mysql_select_db($db_name, $con);
            $id = mysql_real_escape_string($id);
            $result = mysql_query("SELECT * FROM `message` WHERE display=1 AND id=$id");
            $rs = mysql_fetch_array($result);
            echo htmlspecialchars($rs[‘nice‘]) . ‘:<br />&nbsp;&nbsp;&nbsp;&nbsp;‘ . antixss($rs[‘say‘]) . ‘<br />‘;
            mysql_free_result($result);
            mysql_free_result($file);
            mysql_close($con);
        ?></div>
    </center>
  </body>

</html>
so.php
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title>预览留言</title></head>
  
  <body>
    <?php $prenice=$_POST[‘nice‘]; $presay=$_POST[ ‘usersay‘]; include ‘antixss.php‘; ?>
      <center>
        <div id="say" name="say" align="left" style="width:1024px">
          <form method="get" action="./say.php">
            <p>
              <input name="nice" type="hidden" id="nice" value=<?php echo ‘"‘.htmlspecialchars($prenice). ‘"‘; ?>/>
              <input name="usersay" type="hidden" id="usersay" value=<?php echo ‘"‘.antixss($presay). ‘"‘; ?>/>
              <?php echo htmlspecialchars($prenice); ?>:
                <br />    
                <?php echo antixss($presay);?>
                  <br />
                  <br />        
                  <input onclick="return checkform()" type="submit" name="Submit" style="width:600px;height:50px" value="确认提交" /></p></form>
        </div>(提示:再次提醒,xss不保证可以成功,允许留言是为了增加娱乐性,换条思路吧!,因为我也不会xss- -~)</center>
      <script>function checkform() {
          if (say.nice.value == "" || say.usersay.value == "") {
            alert("昵称或留言内容不能为空");
            return false;
          } else {
            return true;
          }</script>
  </body>

</html>
preview.php
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> 
<?php $file = $_GET[‘file‘];
    if ($file == "" || strstr($file, ‘config.php‘)) {
        echo "file参数不能为空!";
        exit();
    } else {
        $cut = strchr($file, "loginxlcteam");
        if ($cut == false) 
        {
            $data = file_get_contents($file);
            $date = htmlspecialchars($data);
            echo $date;
        } else {
            echo "<script>alert(‘敏感目录,禁止查看!但是。。。‘)</script>";
        }
}
about.php
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<?php function antixss($content) {
    preg_match("/(.*)[a](.*)[/a](.*)/", $content, $url);
    $key = array("(", ")", "&", "\\", "<", ">", "‘", "%28", "%29", " on", "data", "src", "eval", "unescape", "innerHTML", "document", "appendChild", "createElement", "write", "String", "setTimeout", "cookie"); 
    //因为太菜,很懒,所以。。。(过滤规则来自Mramydnei)
    $re = $url[2];
    if (count($url) == 0) {
        return htmlspecialchars($content);
    } else {
        for ($i = 0;$i <= count($key);$i++) {
            $re = str_replace($key[$i], ‘_‘, $re);
        }
        return htmlspecialchars($url[1], ENT_QUOTES) . ‘<a href="‘ . $re . ‘">‘ . $re . ‘</a>‘ . htmlspecialchars($url[3], ENT_QUOTES);
    }
} ?>
antixss.php
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<?php
function antiinject($content) {
    $keyword = array("select", "union", "and", "from", ‘ ‘, "‘", ";", ‘"‘, "char", "or", "count", "master", "name", "pass", "admin", "+", "-", "order", "=");
    $info = strtolower($content);
    for ($i = 0;$i <= count($keyword);$i++) {
        $info = str_replace($keyword[$i], ‘‘, $info);
    }
    return $info;
}
?>gt;
antiinject.php

有点东西的:

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 然后继续回到主界面,找到留言口:

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 都疯狂暗示成这样了,当然是要搞点事情啊:

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 找到后台,猜个用户名为admin,放回密码长度不对,说明用户名就是admin了,现在还差一个password:

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 回到刚刚找的注意点,哪里看看可不可以进行注入,毕竟首页已经有大佬说是渗透了,那肯定离不开注入getshell的哇,后来发现so.php的id可以注入,返回的是一串数字:

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在sm.txt里又说userpass的类型是text,那就转化为ascii看看,于是得到密码:

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 解码得到密码,进入后台:

 

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 用file来读一下,emmm没看懂这个马的意思,后来看了一下大佬的解法:

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 是这样用的:

url : http://cms.nuptzj.cn/xlcteam.php?www=preg_replace
pass : wtf

 然后上菜刀,失败了,大概是文件夹可视,文件不可视,哇地一声哭出来:

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冷静一下,观察一下目录,发现可以再次利用file去读取flag

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 最后,可行!:

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后记:贴一些链接

参考WP:https://blog.csdn.net/huanghelouzi/article/details/83421205

直接看源码发现html是经过加密地,解密网站:https://tool.chinaz.com/tools/htmlencode.aspx

php代码美化网站:http://tools.jb51.net/code/phpformat

html代码美化网站:https://tool.chinaz.com/tools/jsformat.aspx

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