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奋斗在产品安全第一线的安全妹子

wordpress 安全防护

看了infosec 出品的<<Protecting WordPress Installations in an IaaS Environment>>,决定给裸奔的wordpress做做加固。

wordpress是国人搭建个人博客的首选,其地位等同于论坛搭建首选discuz(话说,discuz才报出全局变量绕过导致的命令执行大洞,唉,开源的APP都是不产蜜而产getshell的蜂巢)。

wordpress以丰富的插件(插件漏洞)闻名,因此攻击者一般会对wordpress来个指纹识别(除去找暴力破解/社工后台登陆口的快捷方法)

一、wpscan ——wordpress指纹识别及漏洞检查工具

(该网站被丧心病狂的GFW封掉了,翻墙吧psiphon搔年,或者使用渗透套装kali)

(重点不是wpscan,了解攻击才能给出相应防御措施)

a.安装

以ubuntu安装为例

apt-get install libcurl4-gnutls-dev libxml2 libxml2-dev libxslt1-dev ruby-dev build-essential

git clone https://github.com/wpscanteam/wpscan.git

cd wpscan/

gem install bundler && bundle install --without test

b.基本使用

枚举站点信息:用户名、插件、样式等信息

 ruby wpscan.rb --url www.tanjiti.com --enumerate 以下是探测结果样本

[+] URL: http://www.tanjiti.com
[+] Started: Tue Oct 28 15:46:30 2014

[!] The WordPress 'http://www.tanjiti.com/readme.html' file exists
[+] XML-RPC Interface available under: http://www.tanjiti.com/xmlrpc.php
[!] Upload directory has directory listing enabled: http://www.tanjiti.com/wp-content/uploads/

[+] WordPress version 4.0 identified from meta generator

[+] WordPress theme in use: twentyfourteen - v1.2

[+] Name: twentyfourteen - v1.2
 |  Location: http://www.tanjiti.com/wp-content/themes/twentyfourteen/
 |  Style URL: http://www.tanjiti.com/wp-content/themes/twentyfourteen/style.css
 |  Referenced style.css: http://www.tanjiti.com/wp-content/themes/twentyfourteen/style.css
 |  Theme Name: Twenty Fourteen
 |  Theme URI: http://wordpress.org/themes/twentyfourteen
 |  Description: In 2014, our default theme lets you create a responsive magazine website with a sleek, modern des...
 |  Author: the WordPress team
 |  Author URI: http://wordpress.org/

[+] Enumerating installed plugins (only vulnerable ones) ...

   Time: 00:00:37 <==============================================> (880 / 880) 100.00% Time: 00:00:37

[+] No plugins found

[+] Enumerating installed themes (only vulnerable ones) ...

   Time: 00:00:16 <==============================================> (308 / 308) 100.00% Time: 00:00:16

[+] No themes found

[+] Enumerating timthumb files ...

   Time: 00:01:48 <============================================> (2539 / 2539) 100.00% Time: 00:01:48

[+] No timthumb files found

[+] Enumerating usernames ...
[+] Identified the following 1 user/s:
    +----+---------+---------+
    | Id | Login   | Name    |
    +----+---------+---------+
    | 1  | tanjiti | tanjiti |
    +----+---------+---------+

[+] Finished: Tue Oct 28 15:49:34 2014


察看详细的探测信息

ruby wpscan.rb --url www.tanjiti.com --debug-output --random-agent >debug.log

(注意:wpscan 默认User-Agent为WPScan v2.5.1 (http://wpscan.org),扫描器使用常识之一使用正常变化的ua,避免触发WAF之类的防御部署)

基本察看LOG,我们就可以知道wpscan是如何收集信息


例如检查响应头X-Pingback: http://www.tanjiti.com/xmlrpc.php 头 (xmlrpc漏洞)

检查xmlrpc.php (xmlrpc漏洞)

检查robots.txt文件 (敏感信息泄露)

检查readme.html文件(敏感信息泄露)

检查/wp-content/debug.log(敏感信息泄露)

检查配置文件(能够明文读取配置文件基本就是挂掉了),wp-config.php.swo,%23wp-config.php%23,wp-config.orig,wp-config.php_bak,wp-config.original,wp-config.php.orig,wp-config.php.old,.wp-config.php.swp,wp-config.php.save,wp-config.bak,wp-config.txt,wp-config.php~ ,wp-config.save ,wp-config.old,wp-config.php.swp (敏感信息泄露)


识别指纹后,一般会去漏洞信息库中查找可以利用的漏洞,例如MSF


二、MSF-wordpress漏洞利用(已方使用就是漏洞扫描) 

msf > search wordpress

Matching Modules
================

   Name                                                      Disclosure Date  Rank       Description
   ----                                                      ---------------  ----       -----------
   auxiliary/admin/http/wp_custom_contact_forms              2014-08-07       normal     WordPress custom-contact-forms Plugin SQL Upload
   auxiliary/dos/http/wordpress_xmlrpc_dos                   2014-08-06       normal     Wordpress XMLRPC DoS


以前段时间有名的XMLRPC DoS为例(漏洞说明见 [科普]什么是 billion laughs-WordPress与Drupal的DoS攻击有感

msf > use auxiliary/dos/http/wordpress_xmlrpc_dos    
msf auxiliary(wordpress_xmlrpc_dos) > show options

Module options (auxiliary/dos/http/wordpress_xmlrpc_dos):

   Name       Current Setting  Required  Description
   ----       ---------------  --------  -----------
   Proxies                     no        Use a proxy chain
   RHOST                       yes       The target address
   RLIMIT     1000             yes       Number of requests to send
   RPORT      80               yes       The target port
   TARGETURI  /                yes       The base path to the wordpress application
   VHOST                       no        HTTP server virtual host

msf auxiliary(wordpress_xmlrpc_dos) > set RHOST www.tanjiti.com
RHOST => xxx
msf auxiliary(wordpress_xmlrpc_dos) > set TARGETURI /
TARGETURI => /wordpress/wordpress/
msf auxiliary(wordpress_xmlrpc_dos) > run


(再次强调,重点不是msf,了解攻击才能给出相应防御措施)


三、wordpress防护——使用ModSecurity进行防护

安装及规则编写的基础知识见[科普文]ubuntu上安装Apache2+ModSecurity及自定义WAF规则

vim /usr/share/modsecurity-crs/activated_rules/MY.conf

(1) 添加防御xmlrpc漏洞的规则

SecRule REQUEST_URI "@endsWith /xmlrpc.php" "deny,tag:'WEB_ATTACK/WORDPRESS',msg:'block wordpress xmlrpc.php',id:0000003,phase:2"                           

service apache2 restart

使用MSF发送攻击包

msf auxiliary(wordpress_xmlrpc_dos) > use auxiliary/scanner/http/wordpress_pingback_access
msf auxiliary(wordpress_pingback_access) > show options

Module options (auxiliary/scanner/http/wordpress_pingback_access):

   Name       Current Setting  Required  Description
   ----       ---------------  --------  -----------
   Proxies                     no        Use a proxy chain
   RHOSTS                      yes       The target address range or CIDR identifier
   RPORT      80               yes       The target port
   TARGETURI  /                yes       The path to wordpress installation (e.g. /wordpress/)
   THREADS    1                yes       The number of concurrent threads
   VHOST                       no        HTTP server virtual host

msf auxiliary(wordpress_pingback_access) > set RHOSTS www.tanjiti.com
RHOSTS => xxx
msf auxiliary(wordpress_pingback_access) > set TARGETURI /
TARGETURI => /wordpress/wordpress/
msf auxiliary(wordpress_pingback_access) > run



可以看到拦截日志如下

Message: Warning. String match "/xmlrpc.php" at REQUEST_URI. [file "/usr/share/modsecurity-crs/activa
ted_rules/MY.conf"] [line "4"] [id "0000003"] [msg "block wordpress xmlrpc.php"] [tag "WEB_ATTACK/WOR
DPRESS"]


(2) 添加防御wpscan默认扫描头的规则

SecRule REQUEST_HEADERS:User-Agent "@contains wpscan" "t:lowercase,deny,tag:'WEB_ATTACK/WORDPRESS',ms
g:'block wpscanner default useragent',id:0000004,phase:1"

再次运行wpscan,可以看到拦截日志如下

essage: Warning. String match "wpscan" at REQUEST_HEADERS:User-Agent. [file "/usr/share/modsecurity-
crs/activated_rules/MY.conf"] [line "6"] [id "0000004"] [msg "block wpscanner default useragent"] [ta
g "WEB_ATTACK/WORDPRESS"]


大伙可以针对性地添加规则,对个人网站而已,添加白规则较之黑规则会事半功倍,这里的示例规则仅仅是抛砖引玉。


四、wordpress防护——屏蔽敏感信息访问

vim /etc/apache2/apache2.conf

<FilesMatch "\.(sw[po]|old|save|bak|orig(?:inal)?|php(?:~|_bak|\x23))$">
        Require all denied
</FilesMatch>

service apache2 restart

五、wordpress防护——启用安全头

vim /etc/apache2/conf-available/security.conf

(1) 防止在IE9、chrome和safari中的MIME类型混淆攻击

Header set X-Content-Type-Options: "nosniff"

(2) 防止clickjacking,只允许遵守同源策略的资源(和站点同源)通过frame加载那些受保护的资源。 

Header set X-Frame-Options: "sameorigin"

(3) 开启xss防护并通知浏览器阻止而不是过滤用户注入的脚本。

Header set X-XSS-Protection "1;mode=block"

service apache2 restart

六、wordpress防护——登陆口防爆破

一般的方法是设置一个登陆口白名单,但现在越来越多的网站使用cdn服务,明显不再是个好的防护方案

安装Login LockDown 插件,wordpress后台插件管理处搜索即可,设置也超级简单

设置实例:

 如果在5分钟失败3次就会封锁IP60分钟

 



参考:

Protecting WordPress Installations in an IaaS Environment

header的安全配置指南

来源:碳基体

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