Is it safe to use public USB charging stations? [duplicate]

Question

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• Protecting cellphones from USB attacks (a.k.a. Juice Jacking) 2 answers

I'm beginning to see more and more public device charging stations — okay, they're still mostly in airports — that include USB outlets, not just regular power outlets. Are these safe to use? Could someone with time, access and expertise rig one up so that it silently snoops in a connected phone's memory or loads a virus during charging?

To clarify, I know my phone usually asks me what to do if I connect it to something that tries to transfer more than just power, with a dialog box. I'm mostly concerned that there's a way for programs to unilaterally start doing things without a

Do you want to allow program BlahBlah to access your...

confirmation first.

Answer 1

Depends on the phone. If you've disabled USB debugging/file sharing¹, then Android phones are inaccessible via USB until you turn it on.

On the other hand, one can access most files of an iPhone without any special access (this bypasses the pincode lock as well). Desktop applications like IExplore do this. While ssh access won't be available, they still can delete/steal your data, including applications, music, photos, and videos. As well as the configuration of applications (which may include passwords). And they can add their own malware.

^{1 These two are different. Most phones have debugging enabled by default, though you can turn it off. USB sharing is disabled by default, since it requires the SD card to be unmounted (which kills half your apps).}