2024-03-30 09:59:39 +00:00
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2024-03-29 22:46:18 +00:00
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2024-03-30 09:59:39 +00:00
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#align(left, text(20pt)[
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*Misconceptions about NFC*
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#line(length: 70%)
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2024-03-29 22:46:18 +00:00
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#align(left, text(10pt)[*I made a mistake while writing this blog
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post - somehow forgetting that security isn’t unambiguous. You can
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actually skim NFC chips from a certain distance \(having a limited
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distance is still an important factor though!), and though I think some
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of what I said below still applies you’re better off ignoring it all.*
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There are, of course, a whole range of problems with skimming NFC chips
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from a distance so my point - don’t be so worried - would still stand.
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Either way, I recommend you take this with a grain of salt.
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])
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= Introduction
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NFC \(short for Near-Field Communication) is the set of communication
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protocols which allow for #emph[near-field communication] between two
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electronic devices. One of the most prominent uses of this technology
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are contactless transactions - this includes services like Google and
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Apple Pay as well as all of your contactless-enabled cards.
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It’s been a while since my last blog past, but this one will be brief
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too - I’m writing here for the sake of clearing up some misconceptions
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people have about NFC.
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= The Misconceptions
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== Inspiration
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While talking with a friend on a WhatsApp group chat a few days ago
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2024-03-30 09:59:39 +00:00
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about a program I found on my jailbroken iOS device - link("https://github.com/Aemulo")[Aemulo] - I was informed of 'subway
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2024-03-29 22:46:18 +00:00
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skimmers'; devices that could #emph[supposedly] read data from
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contactless-enabled devices \(via NFC) and would be able to emulate
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them.
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The idea behind the above example was that someone with malicious intent
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could place such a device in a public location and take their
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contactless devices for their malicious purposes. When I heard of this,
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my first thought was:
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#link("https://devraza.duckdns.org/blog/hoaxes-overview/")[hoax];, and I
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think that it was rightfully so.
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== What exactly is wrong with this?
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Several things. I’m no expert in cybersecurity - everyone’s a student in
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some way, but I was sure that NFC was, as it’s name implies, for
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#strong[near-field communication];. I’m repeating myself here, but
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that’s kind of the point. Various reliable resources, including
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Wikipedia, show that NFC has a maximum range of only a few centimetres -
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which makes sense, no?
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And yet, whatever source my friend had for 'subway skimmers' gave the
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impression, or otherwise stated, that it would work within a radius of a
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few feet, which is just impossible. Upon voicing my doubts, I was then
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told that 'with a powerful enough antenna, it’s possible'. Hoaxes sure
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are convincing, aren’t they? Unfortunately, I am not able to find the
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source of my friend’s misinformation.
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See, NFC only works within a few centimetres anyways. Even if it could
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#emph[magically] work within a radius of a few feet, you’ve got to take
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in the electromagnetic interference that the clothes and wallets people
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have would bring to any malicious device. The point of electromagnetic
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interference is especially true over a #emph[huge] area of a few feet
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\(relatively), where you’ve got several NFC-enabled devices.
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== Where it’s actually an issue
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Of course, that isn’t to say there aren’t any issues with NFC and
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malicious readers - I’m just saying that the word getting around is
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horribly unrealistic. For example, a #emph[realistic] example of a
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malicious NFC reader would be one placed on the card slots in cash
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machines - you get:
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- The short range (~20 cm)
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- Only one device
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- Lots of devices to read!
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And so, you’ve got someone so much more realistic that poses an actual
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threat!
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= Conclusion
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<conclusion>
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The information above, which I deem accurate, is there. What I suggest
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be taken away from this is pretty much the same as what is was for
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#link("https://devraza.duckdns.org/blog/hoaxes-overview/")[my blog post on hoaxes] - #strong[do some fact-checking!]
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