Critical Remote Code Execution on all Mainstream LG Smartphone Models

Multiple Critical vulnerabilities patched by LG that resides on default keyboard on all
mainstream LG smartphone models. Both the vulnerabilities allow attackers to execute remote code on LG devices with escalated privileges.

Security researchers from Checkpoint disclosed both vulnerabilities to LG and they disclosed a combined patch for both the vulnerabilities(LVE-SMP-170025).

The first vulnerability was due to the use of insecure HTTP connection. When the user defines some other language than English or an update for the existing one the devices reach to the hardcoded server to get the requested language file.

Then the requested language file is downloaded through insecure HTTP connection which exposes to a Man-in-The-Middle attack, allows a remote attacker to download the malicious file instead of the original language file.

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The second one was a validation flaw, the resource file location depends upon the name indicated in the metadata files(files.txt). According to researchers, the resource file within the LG keyboard package sandbox can be modified.

LG’s keyboard grants executable permissions to all downloaded .so extension files. So the attacker could inject a rogue lib file with extension .so extension and it will be marked on the disk as executable.

The keyboard application will load the libs indicated by the Engine properties on the application’s startup and the rogue lib will be loaded as soon as the keyboard process restarts.

“Once we manage to inject the rouge lib inside Engine.properties, all we need to do is wait for the application to restart and load the library. That is our ultimate goal and the moment it is reached then the attack ends.” researchers concluded.

LG also provided patches for RCE(Remote code execution) Vulnerability(LVE-SMP-170025) in LGE IME application that affects the following Android devices with OS 4.4, 5.0, 6.0, 6.0.1, 7.0, 7.1.1, 7.1.2, 8.0.