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NFC while phone locked: what's the actual danger?

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By zequav, Senior Member on 11th November 2012, 03:51 PM
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12th November 2012, 08:16 PM |#11  
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Quote:
Originally Posted by squidder

Some dudes have already used NFC to gain access to a locked gs3 and and upload a trojan automatically and then they have full control of the phone and can have u call premium numbers or whatever the hell they want. So yes there is danger just not likely ATM but in a couple years who knows. When Trojans first came to PCs u didn't really have to worry about it but now u have skids running rampant and I wouldn't be surprised if that happened to android.

Sent from my Galaxy Nexus using xda app-developers app

In a controlled environment. Maybe if your live in New York and frequent the subways and stuff (ie: environments where people get packed together) you have a slight chance of it happening. If you are in those situations, turn NFC off. Otherwise, NFC has a working range of a couple cm's, so in all other cases the guy trying to trojan you will have to get so close that you'll be wondering what the hell he's trying to do.
12th November 2012, 08:28 PM |#12  
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Quote:
Originally Posted by speedyink

In a controlled environment. Maybe if your live in New York and frequent the subways and stuff (ie: environments where people get packed together) you have a slight chance of it happening. If you are in those situations, turn NFC off. Otherwise, NFC has a working range of a couple cm's, so in all other cases the guy trying to trojan you will have to get so close that you'll be wondering what the hell he's trying to do.

Hypothetically, someone could stick some NFC tags in places that people are likely to brush up against or set a purse nearby. Sure the tags aren't free but it would only take one hit to make that back.

Yeah it's still kind of a paranoia thing, and extremely unlikely unless NFC on while locked becomes commonplace. If someone thinks they can make a buck doing it, it will be done.
12th November 2012, 11:36 PM |#13  
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You say that because we are on this topic but the truth is if a guy "accidentally" bumps into u somewhere the last thing u think is he is trying to trojan u. U would prolly let it go and say learn to walk or something similar under ur breath. And then ud be "pwned" by some stupid 1337 skid.


Quote:
Originally Posted by speedyink

In a controlled environment. Maybe if your live in New York and frequent the subways and stuff (ie: environments where people get packed together) you have a slight chance of it happening. If you are in those situations, turn NFC off. Otherwise, NFC has a working range of a couple cm's, so in all other cases the guy trying to trojan you will have to get so close that you'll be wondering what the hell he's trying to do.



Sent from my Galaxy Nexus using xda app-developers app
13th November 2012, 04:25 AM |#14  
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Quote:
Originally Posted by Marisa

Hypothetically, someone could stick some NFC tags in places that people are likely to brush up against or set a purse nearby. Sure the tags aren't free but it would only take one hit to make that back.

I didn't think of that, that's a good point


Quote:
Originally Posted by squidder

You say that because we are on this topic but the truth is if a guy "accidentally" bumps into u somewhere the last thing u think is he is trying to trojan u. U would prolly let it go and say learn to walk or something similar under ur breath. And then ud be "pwned" by some stupid 133...

True, I just wouldn't live in fear of it since the chances are really low. I always leave my NFC off unless I need it anyways, so its a non issue.
13th November 2012, 05:45 AM |#15  
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And I agree completely, just wondering in a few years how much more stuff like this will increase.


Quote:
Originally Posted by speedyink

I didn't think of that, that's a good point




True, I just wouldn't live in fear of it since the chances are really low. I always leave my NFC off unless I need it anyways, so its a non issue.

13th November 2012, 08:08 AM |#16  
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Quote:
Originally Posted by squidder

Some dudes have already used NFC to gain access to a locked gs3 and and upload a trojan automatically and then they have full control of the phone and can have u call premium numbers or whatever the hell they want. So yes there is danger just not likely ATM but in a couple years who knows. When Trojans first came to PCs u didn't really have to worry about it but now u have skids running rampant and I wouldn't be surprised if that happened to android.

Sent from my Galaxy Nexus using xda app-developers app

Show us the link to this. You're either bull****ting or remembering incorrectly. When a stock GS3 is locked, NFC is off; this would not be possible whatsoever.
29th November 2012, 01:30 PM |#17  
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I made a change, but now NfcNci.apk isn't getting built. How I can just build NfcNci.apk so I can see the build error?
Thanks.

Quote:
Originally Posted by zequav

So no real danger if you're not paranoid, then. Good to know. A pity we won't have it in CM; I don't see any problem if it's off by default and there is a warning when you enable it.



I usually don't trust random_guy's apks. I'd rather compile it myself. The patch is simple:

Code:
diff --git a/src/com/android/nfc/NfcService.java b/src/com/android/nfc/NfcService.java
index 06642f7..793cc28 100755
--- a/src/com/android/nfc/NfcService.java
+++ b/src/com/android/nfc/NfcService.java
@@ -132,7 +132,7 @@ public class NfcService extends Application implements DeviceHostListener {
     static final int ROUTE_ON_WHEN_SCREEN_ON = 2;
 
     /** minimum screen state that enables NFC polling (discovery) */
-    static final int POLLING_MODE = SCREEN_STATE_ON_UNLOCKED;
+    static final int POLLING_MODE = SCREEN_STATE_OFF;
 
     // for use with playSound()
     public static final int SOUND_START = 0;

2nd September 2018, 05:49 PM |#18  
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Quote:
Originally Posted by zequav


I decided to compile my own CM10 KANGs from now on with a patched NfcService.java (running great right now).

I want to do this for my phone, Samsung Galaxy S6 - Sprint Variant. Can you elaborate on how to proceed? I have compiled ROMs successfully in the past. I need to know where the get the patched NfxService.java from.
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