WordPress Stop User Enumeration 1.3.8 User Enumeration

`Details  
================  
Software: Stop User Enumeration  
Version: 1.3.8  
Homepage: https://wordpress.org/plugins/stop-user-enumeration/  
Advisory report: https://security.dxw.com/advisories/stop-user-enumeration-rest-api/  
CVE: Awaiting assignment  
CVSS: 5 (Medium; AV:N/AC:L/Au:N/C:P/I:N/A:N)  
  
Description  
================  
Stop User Enumeration allows user enumeration via the REST API  
  
Vulnerability  
================  
Stop User Enumeration optionally allows stopping user enumeration via the WordPress REST API. When that option is enabled, requests toA /wp-json/wp/v2/users are blocked and return an error like this:  
{\"code\":\"rest_cannot_access\",\"message\":\"Only authenticated users can access the User endpoint REST API.\",\"data\":{\"status\":401}}  
It also successfully blocks requests such asA /?rest_route=/wp/v2/users.  
The blocking relies upon the following comparison:  
if( preg_match(\'/users/\', $_SERVER[\'REQUEST_URI\']) !== 0 ) {  
On the surface this looks like it should work.A And itA seems like we canat get around the restriction by sending a POST request with the parameter rest_route=/wp/v2/users, because WordPress thinks we want to create a user and responds with an error.  
However, the REST API allows simulating differentA request types. As such, we can perform a POST request with the ausersa string in the body of the request, and tell the REST APIA to act like itas received a GET request.  
  
Proof of concept  
================  
curl http://localhost/?_method=GET -d rest_route=/wp/v2/users  
  
Mitigations  
================  
Upgrade to versionA 1.3.9 or later.  
  
Disclosure policy  
================  
dxw believes in responsible disclosure. Your attention is drawn to our disclosure policy: https://security.dxw.com/disclosure/  
  
Please contact us on [email protected] to acknowledge this report if you received it via a third party (for example, [email protected]) as they generally cannot communicate with us on your behalf.  
  
This vulnerability will be published if we do not receive a response to this report with 14 days.  
  
Timeline  
================  
  
2017-05-16: Discovered  
2017-07-18: Reported to vendor viaA [email protected]  
2017-07-18: First response from vendor  
2017-07-19: Vendor reports issue fixed in version 1.3.9  
2017-07-25: Published  
  
  
  
Discovered by dxw:  
================  
Tom Adams  
Please visit security.dxw.com for more information.  
  
  
  
  
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