h4ck/lg_webOS

LG webOS

• TV
• digging
  • nmap
  • sniffing
    • on boot
    • channel search
    • application marketplace
• impersonating
  • channel guide
  • application update

TV

name	value
model	43UH6100
product	3.0
firmware	4.30.40
features	app marketplace, live TV listings
vulnerabilities	all phone-home calls are done over HTTP

the 43UH6100 is a 'smart' TV, running LG's webOS since it is a fair assumption it is running OpenWrt underneath, the original goal was rooting the device, but initial investigations showed some other interesting vectors.

digging

nmap

from nmap -PN -sV <device, we get:

PORT     STATE SERVICE  VERSION
1175/tcp open  upnp
3000/tcp open  http     LG smart TV http service
3001/tcp open  ssl/http LG smart TV http service
9998/tcp open  http     Google Chromecast httpd

aside from the obvious flag running of both HTTP and HTTPS versions of (likely) the same service, interested to see that the Chromecast plugged in to the TV is also being exposed on the same IP as the TV.

since there is an LG smart TV app available for Android/iOS, assuming that there is an API of some sort running on 3000 or 3001, so:

$ curl http://<device>:3000
Hello world

we see the same response on 3001, but have to use -k as the device uses a self-signed certificate.

so, something is there, we just don't know how to talk to it yet.

sniffing

switching tactics and connected the TV to a wireless network that has a tap, and we start to see some interesting things:

on boot

every time the TV starts up, within 30 seconds, it calls home:

POST /CheckSWAutoUpdate.laf HTTP/1.1
Accept: */*
User-Agent: User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)
Host: snu.lge.com:80
Connection: Keep-Alive
Content-type: application/x-www-form-urlencoded
Content-Length: 572

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

HTTP/1.1 200 OK
Date: Wed, 16 Nov 2016 08:23:56 GMT
Content-length: 508
Content-type: application/octet-stream;charset=UTF-8
Pragma: no-cache;
Expires: -1;
Content-Transfer-Encoding: binary;

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

that looks a lot like base64 encoded data, and when decoded, yields

request:

<REQUEST>
  <PRODUCT_NM>webOSTV 3.0</PRODUCT_NM>
  <MODEL_NM>HE_DTV_W16P_AFADATAA</MODEL_NM>
  <SW_TYPE>FIRMWARE</SW_TYPE>
  <MAJOR_VER>04</MAJOR_VER>
  <MINOR_VER>30.40</MINOR_VER>
  <COUNTRY>US2</COUNTRY>
  <COUNTRY_GROUP>US</COUNTRY_GROUP>
  <DEVICE_ID>de:ad:be:ef:ca:fe</DEVICE_ID>
  <AUTH_FLAG>N</AUTH_FLAG>
  <IGNORE_DISABLE>N</IGNORE_DISABLE>
  <ECO_INFO>01</ECO_INFO>
  <CONFIG_KEY>00</CONFIG_KEY>
  <LANGUAGE_CODE>en-US</LANGUAGE_CODE>
</REQUEST>

pretty standard, but the auth_flag, ignore_disable and config_key values are potentially interesting

response:

<RESPONSE>
  <RESULT_CD>900</RESULT_CD>
  <MSG>Success</MSG>
  <REQ_ID>00000000000000000001</REQ_ID>
  <IMAGE_URL></IMAGE_URL>
  <IMAGE_SIZE></IMAGE_SIZE>
  <IMAGE_NAME></IMAGE_NAME>
  <UPDATE_MAJOR_VER></UPDATE_MAJOR_VER>
  <UPDATE_MINOR_VER></UPDATE_MINOR_VER>
  <FORCE_FLAG></FORCE_FLAG>
  <KE></KE>
  <GMT>16 Nov 2016 08:23:56 GMT</GMT>
  <ECO_INFO>01</ECO_INFO>
  <CDN_URL></CDN_URL>
  <CONTENTS></CONTENTS>
</RESPONSE>

much more interesting than the request:

key	assumption
IMAGE_URL	the URL of a firmware update
IMAGE_SIZE	the size of the firmware update - are they doing this instead of checksum?
IMAGE_NAME	the name of the firmware update - not sure why this is necessary
UPDATE_MAJOR_VER	the major version of the firmware update
UPDATE_MINOR_VER	the minor version of the firmware update
FORCE_FLAG	whether or not to force the update - unclear if true
CDN_URL	URL that the firmware update is available at
CONTENTS	none

half an hour of playing around with both the input and output here didn't yield any immediate results, but there is definite potential.

to speed this along, observe a session where the TV updated its firmware from the manufacturer

channel search

foo

application marketplace

bar

impersonating

baz

channel guide

barney

application update

fizzbang