[Android Apps and Games] SteveKatz:
Be careful with KingRoot; my SIM card number may have been cloned

So, I'm posting to follow up on my own question. What happened was that I bought a brand new Tracfone LG L62VL from the Home Shopping Network. For those that aren't Tracfone users, a little background is required. Tracfones usually don't include any service. You buy the phone outright and then have to buy a one-year airtime card separately for 100 USD. However, QVC and HSN sell Tracfones with one year of service included as a part of the promotion. It's a great deal for users who don't require a high performance phone and only use a minimal amount of cell tower data. The one year of service included with my phone never sells for less than 85 USD at the maximum discount. I paid 95 for the bundle, so the effective cost to buy the LG L62VL outright was only 10 USD. Not bad, considering that the L62VL would have been considered an excellent mid-range phone just three or four years ago.

The downside is that the promotional service is a special and poorly documented arrangement between Tracfone and HSN/QVC. You do not receive a conventional Tracfone airtime card whose number could be used to add service to any Tracfone. Instead, the phone's SIM card number is on file with Tracfone so that the promotional time is supposed to get added to that one, individual phone bearing that SIM card number during activation. You lose the promotional service if anything happens to that particular phone. For example, the promotional service does not transfer if the phone dies and has to be replaced with a different phone.

So, I received my new L62VL on 7/20/2017. I didn't want to risk trying out KingRoot after activation for fear of screwing up the promotional minutes. Instead, I skipped activation, accessed xda-developers.com via the phone's browser over wi-fi, and downloaded the latest apk.

Good news, it worked. Bad news, the phone started displaying the message "invalid SIM card" after re-running KingRoot a few times after reboots. I had done absolutely nothing unorthodox except to run KingRoot. As noted in my original post, a hard reset did not fix the problem although it does seem to have eliminated KingRoot.

I called Tracfone on 7/24 and had to be elevated to a second level of technical support. The phone could not be activated. The ultimate explanation given by the second level Tracfone tech (after a total of 1.5 hours) is that the SIM card number is showing up as already in use. I was asked if I had ever put a SIM card from another phone into the new L62VL (that's a "no") or had put the L62VL's SIM card into another phone (also a "no"). Tracfone states that they are

shipping a new SIM card to me.

Granted, the Tracfone techs are not the sharpest knives in the drawer, and I don't (and you shouldn't) take their explanation as an absolute truth. However, the KingRoot team has admitted that KingRoot reads your SIM card number and sends it to the KingRoot server, although they also say that the numbers are not accessed or stored. Assuming the truth of Tracfone's explanation, I have come to the personal opinion that my SIM card number was cloned as a result of running KingRoot. One plausible scenario is that KingRoot's server is under a man in the middle attack, given that valuable information passes into that server.

I would very much like to hear your alternative (and far more expert) opinions.

Thanks in advance, Steve