9 ms·

I would even dispute it being as bad as goto fail. For this to work both client and server must be vulnerable and the attacker must be in a privileged network p

I would even dispute it being as bad as goto fail. For this to work both client and server must be vulnerable and the attacker must be in a privileged network position. A malicious server can do it, but it's significantly more difficult to exploit this than goto fail. Edit: agl has a good writeup of the bug and what it might take to exploit https://www.imperialviolet.org/2014/06/05/earlyccs.html https://www.imperialviolet.org/2014/06/05/earlyccs.html

mnw21cam 12y ago
It would mean (for example) that your local coffee shop could MITM their clients connecting to the bank through their free wifi. Being in a privileged network position isn't that hard, with all the mobile devices flying around everywhere.
- jacquesm 12y ago
  That would be mostly limited to Konqueror (does anybody still use that?) and Google Chrome on Android. Which other browsers use OpenSSL?
- reaperhulk 12y ago
  I'm not claiming that being in a position to MITM is super difficult, but in your given example it's unlikely that you'd be vulnerable since web browsers (outside of Chrome on Android) don't use OpenSSL. Additionally, there is a degree of sophistication required to attempt this attack that exceeds that of goto fail. So again, bad, but not as bad as goto fail.
- ZoFreX 12y ago
  Completely unscientific observation: More people in my local coffee shop are using phones than laptops, and more of those phones are Androids than iOS. I know anecdotally that the Chrome browser is very popular on Android. I would give even odds on there being more people to exploit with this than there were with goto fail.
  - PhantomGremlin 12y ago
    I use coffee shop WiFi when I access useless sites such as Drudge Report. However, it's not hard to either a) switch to cellular on a phone before accessing something important like a banking site or b) use something like Personal Hotspot together with a phone switched to cellular to allow a laptop to access something important like a banking site That's what I do. I certainly don't trust random WiFi for sensitive communications. IMO you're much safer relying on AT&T or Verizon to connect you to key sites via cellular service rather than thru WiFi. OTOH I know that in the past AT&T has automatically switched my iPad from cellular to WiFi when I was at a coffee shop that had service from them. So this may be a little tricky in practice.
- thegeomaster 12y ago
  Even worse, from what I've observed, such networks are often not secure even against a trivial ARP spoof attack, so anyone connecting to the coffee shop Wi-Fi could mount this attack.
  - e12e 12y ago
    Is there any reasonable way to make them secure against ARP spoofing? As I understand it, it would require individual login from all clients (some form of 802.1x)? And even if you do protect against ARP spoofing via 802.1x -- you would still need some kind of shared secret/certificate scheme to avoid a fake access point? As anyone sitting next to you is likely to be able to provide a stronger signal than the hotspot... Reminds me that I had an idea to wrap up some kind of hot-spot with an easy to use internet cafe style time-limited access software distribution and offer up to local businesses... I suppose these days providing a screen for qr-code sharing of details would be a viable option...
    - apendleton 12y ago
      To make them immune to the ARP spoofing in the general case is hard, but as I understand it, to make them immune to the specific case of clients other than the gateway impersonating the gateway (which is what people want to do for most MitM) is pretty straightforward. The access point is probably itself the gateway most of the time, so it knows the gateway's MAC (its own), and it can reliably refuse to forward ARP packets for other MACs claiming to be the gateway.
      - e12e 12y ago
        > it can reliably refuse to forward ARP packets for other MACs claiming to be the gateway. I thought most wireless lans acted as an (shared medium) ethernet, that is, they allow clients to send packets directly client to client? That is, I thought [ed:naughty]-client could just broadcast ARP packets directly to the clients? Or does perhaps (ethernet) broadcast traffic go through the gateway? None of this helps with a rouge AP, of course -- so it might be a bit academic.
ctz 12y ago
You're right. I was mainly talking about the impact of exploitation, rather than the conditions necessary for it.
mentat 12y ago
Privileged network positions are sort of a joke with the current state of wifi security.

mnw21cam 12y ago

It would mean (for example) that your local coffee shop could MITM their clients connecting to the bank through their free wifi. Being in a privileged network position isn't that hard, with all the mobile devices flying around everywhere.

jacquesm 12y ago
That would be mostly limited to Konqueror (does anybody still use that?) and Google Chrome on Android. Which other browsers use OpenSSL?
reaperhulk 12y ago
I'm not claiming that being in a position to MITM is super difficult, but in your given example it's unlikely that you'd be vulnerable since web browsers (outside of Chrome on Android) don't use OpenSSL. Additionally, there is a degree of sophistication required to attempt this attack that exceeds that of goto fail. So again, bad, but not as bad as goto fail.
ZoFreX 12y ago
Completely unscientific observation: More people in my local coffee shop are using phones than laptops, and more of those phones are Androids than iOS. I know anecdotally that the Chrome browser is very popular on Android. I would give even odds on there being more people to exploit with this than there were with goto fail.
- PhantomGremlin 12y ago
  I use coffee shop WiFi when I access useless sites such as Drudge Report. However, it's not hard to either a) switch to cellular on a phone before accessing something important like a banking site or b) use something like Personal Hotspot together with a phone switched to cellular to allow a laptop to access something important like a banking site That's what I do. I certainly don't trust random WiFi for sensitive communications. IMO you're much safer relying on AT&T or Verizon to connect you to key sites via cellular service rather than thru WiFi. OTOH I know that in the past AT&T has automatically switched my iPad from cellular to WiFi when I was at a coffee shop that had service from them. So this may be a little tricky in practice.
thegeomaster 12y ago
Even worse, from what I've observed, such networks are often not secure even against a trivial ARP spoof attack, so anyone connecting to the coffee shop Wi-Fi could mount this attack.
- e12e 12y ago
  Is there any reasonable way to make them secure against ARP spoofing? As I understand it, it would require individual login from all clients (some form of 802.1x)? And even if you do protect against ARP spoofing via 802.1x -- you would still need some kind of shared secret/certificate scheme to avoid a fake access point? As anyone sitting next to you is likely to be able to provide a stronger signal than the hotspot... Reminds me that I had an idea to wrap up some kind of hot-spot with an easy to use internet cafe style time-limited access software distribution and offer up to local businesses... I suppose these days providing a screen for qr-code sharing of details would be a viable option...
  - apendleton 12y ago
    To make them immune to the ARP spoofing in the general case is hard, but as I understand it, to make them immune to the specific case of clients other than the gateway impersonating the gateway (which is what people want to do for most MitM) is pretty straightforward. The access point is probably itself the gateway most of the time, so it knows the gateway's MAC (its own), and it can reliably refuse to forward ARP packets for other MACs claiming to be the gateway.
    - e12e 12y ago
      > it can reliably refuse to forward ARP packets for other MACs claiming to be the gateway. I thought most wireless lans acted as an (shared medium) ethernet, that is, they allow clients to send packets directly client to client? That is, I thought [ed:naughty]-client could just broadcast ARP packets directly to the clients? Or does perhaps (ethernet) broadcast traffic go through the gateway? None of this helps with a rouge AP, of course -- so it might be a bit academic.

ctz 12y ago

You're right. I was mainly talking about the impact of exploitation, rather than the conditions necessary for it.

mentat 12y ago

Privileged network positions are sort of a joke with the current state of wifi security.