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Replicant OS Developers Find Backdoor In Samsung Galaxy Devices
An anonymous reader writes "Developers of the Free Software Foundation-endorsed Replicant OS have uncovered a backdoor through Android on Samsung Galaxy devices and the Nexus S. The research indicates the proprietary Android versions have a blob handling communication with the modem using Samsung's IPC protocol and in turn there's a set of commands that allow the modem to do remote I/O operations on the phone's storage. Replicant's open-source version of Android does away with the Samsung library to fend off the potential backdoor issue."
Actually, the article states that Cyanogenmod uses the same blob as well.
Modem can ask the APU app to write/read selected files and do some other file system operations. Why would modem want to read/write arbitrary files on user's file system and what and how could invoke such behavior of the modem? The answer is up to your imagination.
Well, in fact many other phones don't need any backdoor to do the same as lots of them have modems directly connected to main RAM, exposing it to monitoring or even manipulation by the closed and strictly secured modem firmware.
That's why projects like Neo900 opt for clear APU<->modem separation as host<->peripheral, together with power and antenna usage monitoring and fully free software stack on APU side.
No. The modem can write to your OS. Anyone can communicate with your modem, even Ham radio operators. Granted, exploiting this would be a huge technological challenge... unless of course this was placed there intentionally and they know exactly what to send to your modem to get it to do what they want.