LG G3 Arbitrary File Retrieval from Cloud Services
LG SmartShare.Cloud is a gateway application provided by LG to access various cloud services such as Dropbox and Box from native applications. A vulnerability was found when an LG device connected to a WiFi network, the SmartShare.Cloud application would start an HTTP Server listening on all interfaces. If an attacker knew the name of a file stored on the Cloud storage, they could retrieve the file without authentication or user interaction.
An attacker on the same network as a user who has configured Dropbox or Box as their cloud backup store using LG SmartShare.Cloud application could retrieve any media file from the Cloud storage of the victim as long as they knew the file name.
This was due to the SmartShare.Cloud application launching an unauthenticated HTTP Server listening on all interfaces while connected to a WiFi network.
An interim workaround would be to ensure that LG SmartShare.Cloud is not configured to backup local files. Full remediation will require the patch to be applied.
Upgrade to the latest version via an OTA (over the air) update. Version 2.4.0 has mitigated this issue.
When setting up a cloud backup account, such as Dropbox, the application made available a local HTTP Server on port 9999. This allowed native applications to make requests to backup or retrieve files from the cloud account. However, when the handset was connected to WiFi network, the HTTP Server was made available on all interfaces. The HTTP Server can be queried from another host on the same network to download a known file from the Dropbox account. For example, performing the following GET request from the attacking host will result in the file specified in the file parameter to be downloaded.
The SmartShare.Cloud application accepted this request without requiring any authentication. An attacker could scan a network for any devices which have this port open and proceed with the above mentioned attack.