Are hidden incoming SMS common for C&C?

Did I stumble on some evidence of a compromise? Or am I just being paranoid? I'm not sure if what I'm seeing would be normal for android malware these days.

Carrier logs for the phone's one account show incoming messages from a single origin number, at a rate of about 50 per day, for a week. On the device, there is no record of this number - no texts or calls. It is an unknown number. The block lists on …

account android android malware carrier compromise evidence hidden logs malware messages normal origin phone rate single sms