5 ms·

Proves again, there is really no excuse not to use HTTPS for everything. Encryption/certificate validation make it much harder to pull of a MITM attack like th

Proves again, there is really no excuse not to use HTTPS for everything. Encryption/certificate validation make it much harder to pull of a MITM attack like this, especially by companies and small repressive governments.

pmjordan 16y ago
With this scale of access to the network infrastructure[1], I'd be worried about them injecting drive-by downloads of browser exploits which install trust for a root certificate controlled by the government. Once in place, MITM attacks on https are possible. The tricky bit would be telling apart requests from compromised machines and uncompromised ones. (attempting to MITM the latter will cause the browser to start jumping up and down, potentially raising suspicion) Even more scary is the thought experiment that Microsoft might cooperate with the Tunisian government and allow installing trust for such a root certificate via the windows update mechanism. (I have no evidence that this actually happens, it just seems a convenient vector) [1] They're under no time pressure and can transparently proxy every single TCP connection and IP packet if they so desire. They control DNS.
- wladimir 16y ago
  If you want scary, what about bribing Intel and AMD to include 'propietrary instructions' for your government?
  - pmjordan 16y ago
    Seems a little far-fetched and overly complicated for carrying out a practical attack.
    - wladimir 16y ago
      Yes, but at least it would work for practically everything, and it seems most effective to start at the source if you're bribing big companies anyway. If you bribe Microsoft you'll only get the IE (and possibly Windows) users, and privacy-minded individuals will likely be avoiding those already. Also it's pretty much impossible to patch and protect against, even if you know the exploit exists.
      - pmjordan 16y ago
        You'd still need some kind of software support to trigger the exploit. At which point you may as well go with a software-only attack.
        wladimir 16y ago
        Naah, if it's simply a few added instructions I agree with you. But let's think in a wider scope (disclaimer: this is not my idea, I remember reading about it a long time ago): what if a certain cryptographic "magic code" at the beginning of a memory page would trigger the execution of arbitrary code embedded in that page? Such a thing could be triggered over the network, wireless through bluetooth/wifi, or by specially crafted images on a webpage, or whatever creative technique you can think of. It'd effectively give the govt instant root access to any device with the affected CPUs.
        stcredzero 16y ago
        Stuff like this would be easy to hide in the guise of "Hardware DRM."
        wladimir 16y ago
        Yes, I guess on-processor DRM and any kind of virtualisation (will the real hypervisor please stand up?) are prime suspects for this kind of thing. But they are also the most obvious, it could be cramped into everything. It'd be mighty interesting to tear apart / scan / reverse engineer some modern CPUs like they did with the 6502. Then again, these beasts are so complex that's similar to looking for a needle in a galaxy-sized haystack.
jrockway 16y ago
I guess SSL is an improvement. Now you just have to trust 2000 companies and anyone controlling their purse strings, instead of having to trust everyone. You feel safe, which is much better than being safe...
- varjag 16y ago
  So what you are trying to convey, there is no advantage to using SSL vs. plain connection? I wonder why then they shut down SSL in my home country during elections..
  - skorgu 16y ago
    There's no advantage against a motivated, state-sized actor. Against other attackers there is still substantial advantage.
    - varjag 16y ago
      Let's say there is no advantage against (maybe) the U.S. government. I fail to see how any other state or entity would be able to manipulate certificate authority chain in general.
      - mooism2 16y ago
        If you are a certificate authority, you can issue certificates for any domain. There is nothing in the technology preventing you from issuing a whitehouse.gov certificate merely because you are based in Iran, for example.
        varjag 16y ago
        Who is going to sign it?
        mooism2 16y ago
        Who is going to sign what? If you mean the certificates that the certificate authority issues, then the certificate authority signs them itself. If you mean who signs the certificate authority's authority certificate, then either another certificate authority signs it, or the certificate authority signs it itself and pays the browser makers to include it as a root certificate in their browsers. I'm not sure what you're trying to get at?
mooism2 16y ago
I agree TLS should be more widely used. But... When the government or ISP in question controls its own certificate authority (and many do), they can MITM you even over HTTPS. Yes, it's another speedbump for them to get over. No, it's not going to stop them. The X.509 security model is broken and needs fixing or replacing.
- chaitanya 16y ago
  Are there any certifying authorities which can be considered relatively free of government/corporate control?
  - wrs 16y ago
    That doesn't matter until browsers start paying attention to which authority signed the certificate.
iuguy 16y ago
The simple answer for small repressive governments is to block the HTTPS login form so you have to fall back to HTTP. ATI has complete control of all Internet access in Tunisia. You're just not going to get through them unless you can find a way through. In some countries I work in we routinely come across censorship and all kinds of dodgy goings on, so we have a variety of tunnelling methods (VPN, SSH, ICMPTX, DNSTX, Tor and a few non-public tunnelling options). For the most part as long as you can terminate a connection in somewhere you're fairly comfortable with you're better off. Also don't make the mistake of feeling that the US, UK or EU are automatically comfortable options. It all depends what you're doing with the data. A little common sense goes a long way.
- wladimir 16y ago
  Of course, governments can completely block port 443, but that will make so many internet sites unusable they could just as well completely pull the plug. And with 'HTTPS everywhere', I also mean removing the HTTP fallback. Fallbacks to plaintext (that can be triggered by a MITM) are indeed obvious backdoors that should be avoided in any protocol.
- SimplePast 16y ago
  Correct ! Facebook https is already blocked !
pornel 16y ago
http://www.google.co.uk/search?q=site%3Atn+inurl%3Ahttps http://www.google.co.uk/search?q=site%3Atn+inurl%3Ahttps Quite a few of Tunisian websites are signed by "Agence Nationale de Certification Electronique". Also, there so many intermediate CA's that I find it hard to believe that the system isn't broken: https://www.eff.org/files/colour_map_of_CAs.pdf https://www.eff.org/files/colour_map_of_CAs.pdf (via https://www.eff.org/observatory https://www.eff.org/observatory) We already had UAE government successfully MITM-ing SSL by forcing CyberTrust-delegated CA to forge a certificate: http://www.schneier.com/blog/archives/2010/09/uae_man-in-the-.html http://www.schneier.com/blog/archives/2010/09/uae_man-in-the...

pmjordan 16y ago

With this scale of access to the network infrastructure[1], I'd be worried about them injecting drive-by downloads of browser exploits which install trust for a root certificate controlled by the government. Once in place, MITM attacks on https are possible. The tricky bit would be telling apart requests from compromised machines and uncompromised ones. (attempting to MITM the latter will cause the browser to start jumping up and down, potentially raising suspicion) Even more scary is the thought experiment that Microsoft might cooperate with the Tunisian government and allow installing trust for such a root certificate via the windows update mechanism. (I have no evidence that this actually happens, it just seems a convenient vector) [1] They're under no time pressure and can transparently proxy every single TCP connection and IP packet if they so desire. They control DNS.

wladimir 16y ago
If you want scary, what about bribing Intel and AMD to include 'propietrary instructions' for your government?
- pmjordan 16y ago
  Seems a little far-fetched and overly complicated for carrying out a practical attack.
  - wladimir 16y ago
    Yes, but at least it would work for practically everything, and it seems most effective to start at the source if you're bribing big companies anyway. If you bribe Microsoft you'll only get the IE (and possibly Windows) users, and privacy-minded individuals will likely be avoiding those already. Also it's pretty much impossible to patch and protect against, even if you know the exploit exists.
    - pmjordan 16y ago
      You'd still need some kind of software support to trigger the exploit. At which point you may as well go with a software-only attack.
      - wladimir 16y ago
        Naah, if it's simply a few added instructions I agree with you. But let's think in a wider scope (disclaimer: this is not my idea, I remember reading about it a long time ago): what if a certain cryptographic "magic code" at the beginning of a memory page would trigger the execution of arbitrary code embedded in that page? Such a thing could be triggered over the network, wireless through bluetooth/wifi, or by specially crafted images on a webpage, or whatever creative technique you can think of. It'd effectively give the govt instant root access to any device with the affected CPUs.
        stcredzero 16y ago
        Stuff like this would be easy to hide in the guise of "Hardware DRM."
        wladimir 16y ago
        Yes, I guess on-processor DRM and any kind of virtualisation (will the real hypervisor please stand up?) are prime suspects for this kind of thing. But they are also the most obvious, it could be cramped into everything. It'd be mighty interesting to tear apart / scan / reverse engineer some modern CPUs like they did with the 6502. Then again, these beasts are so complex that's similar to looking for a needle in a galaxy-sized haystack.

jrockway 16y ago

I guess SSL is an improvement. Now you just have to trust 2000 companies and anyone controlling their purse strings, instead of having to trust everyone. You feel safe, which is much better than being safe...

varjag 16y ago
So what you are trying to convey, there is no advantage to using SSL vs. plain connection? I wonder why then they shut down SSL in my home country during elections..
- skorgu 16y ago
  There's no advantage against a motivated, state-sized actor. Against other attackers there is still substantial advantage.
  - varjag 16y ago
    Let's say there is no advantage against (maybe) the U.S. government. I fail to see how any other state or entity would be able to manipulate certificate authority chain in general.
    - mooism2 16y ago
      If you are a certificate authority, you can issue certificates for any domain. There is nothing in the technology preventing you from issuing a whitehouse.gov certificate merely because you are based in Iran, for example.
      - varjag 16y ago
        Who is going to sign it?
        mooism2 16y ago
        Who is going to sign what? If you mean the certificates that the certificate authority issues, then the certificate authority signs them itself. If you mean who signs the certificate authority's authority certificate, then either another certificate authority signs it, or the certificate authority signs it itself and pays the browser makers to include it as a root certificate in their browsers. I'm not sure what you're trying to get at?

mooism2 16y ago

I agree TLS should be more widely used. But... When the government or ISP in question controls its own certificate authority (and many do), they can MITM you even over HTTPS. Yes, it's another speedbump for them to get over. No, it's not going to stop them. The X.509 security model is broken and needs fixing or replacing.

chaitanya 16y ago
Are there any certifying authorities which can be considered relatively free of government/corporate control?
- wrs 16y ago
  That doesn't matter until browsers start paying attention to which authority signed the certificate.

iuguy 16y ago

The simple answer for small repressive governments is to block the HTTPS login form so you have to fall back to HTTP. ATI has complete control of all Internet access in Tunisia. You're just not going to get through them unless you can find a way through. In some countries I work in we routinely come across censorship and all kinds of dodgy goings on, so we have a variety of tunnelling methods (VPN, SSH, ICMPTX, DNSTX, Tor and a few non-public tunnelling options). For the most part as long as you can terminate a connection in somewhere you're fairly comfortable with you're better off. Also don't make the mistake of feeling that the US, UK or EU are automatically comfortable options. It all depends what you're doing with the data. A little common sense goes a long way.

wladimir 16y ago
Of course, governments can completely block port 443, but that will make so many internet sites unusable they could just as well completely pull the plug. And with 'HTTPS everywhere', I also mean removing the HTTP fallback. Fallbacks to plaintext (that can be triggered by a MITM) are indeed obvious backdoors that should be avoided in any protocol.
SimplePast 16y ago
Correct ! Facebook https is already blocked !

pornel 16y ago

http://www.google.co.uk/search?q=site%3Atn+inurl%3Ahttps http://www.google.co.uk/search?q=site%3Atn+inurl%3Ahttps Quite a few of Tunisian websites are signed by "Agence Nationale de Certification Electronique". Also, there so many intermediate CA's that I find it hard to believe that the system isn't broken: https://www.eff.org/files/colour_map_of_CAs.pdf https://www.eff.org/files/colour_map_of_CAs.pdf (via https://www.eff.org/observatory https://www.eff.org/observatory) We already had UAE government successfully MITM-ing SSL by forcing CyberTrust-delegated CA to forge a certificate: http://www.schneier.com/blog/archives/2010/09/uae_man-in-the-.html http://www.schneier.com/blog/archives/2010/09/uae_man-in-the...