Is it possible to hack a phone just inputting dialer codes?

Question

I'm currently in Germany, and today a woman asked if she could borrow my phone on the street, as she needed to make an urgent call. The thing is that I lended her my phone and, while I was making sure my wallet was safe (she gave me a very weird vibe), I noted she was inputting some dialer code (something like #number#othernumber) on my (Android; Samsung) phone and doing something strange with hers. When I noticed it, she hid her phone, she moved a bit doing as if she was calling, and then I asked her to give my phone back. She did and told me that "the person she was calling must be asleep", gave my phone back, and then quickly went away.

I checked the call she did and it lasted 5 seconds, and there is only a number and no trace of the code she inputted on the dialer (I'm pretty sure I saw a couple of # symbols on the dialer). A couple of seconds after, and just for "security" I turned off my phone, but later I had to turn it on again to check some emails.

Some questions:

1. Is it possible to list all the codes dialed in my phone in order to check what she did?
2. What could she have extracted from my phone? Could she have installed something? I had Bluetooth turned off, and only phone calls and internet could be used.

Any help would be greatly appreaciated, as there are bank apps on my phone that I think could have sensible information.

Answer 1

She could of done 2 things that would make you pay something extra:

• Hailed a number that overtaxes and since the first minute is most of the time taxed by default no matter the duration up to 60 seconds she actually did make some amount of currency with the few seconds when it was active

• Sent a text message to a special service, again, overtaxing you

By your description, it was a call, not a text. Using "#" parameters she left no trace of the destination. Only your mobile operator could help you identify the destination unless you had a key-logger active.