6 ms·

Right advice, wrong reason. Any moderate sized company will be aware that SSL makes it harder for their corporate traffic monitoring to work. They don't want SS

by CHY872 12y ago

Right advice, wrong reason. Any moderate sized company will be aware that SSL makes it harder for their corporate traffic monitoring to work. They don't want SSL usage to render their monitoring software useless, so they install their own SSL root certs on machines, and relentlessly MITM all SSL traffic. In this case, how can SSL help? More to the point, the corporation generally has a right to monitor all computer usage you do on their machines - so posting disparaging comments about them on their own machines is a particularly dumb idea - not withstanding the Google Chrome 'Incognito Mode cannot protect you against people standing behind you' warning.

adrianpike 12y ago
What's an easy way to find out if they're doing this? Taking a look at the certs installed in my system, unless I see "BigCo MITM Cert", I don't have a ton of insight on what certs are and aren't supposed to be there. Also, I'm not 100% on where all certs would be found, and short of looking at the trust chain on each site I visit, I'm not actually sure how to know.
- freehunter 12y ago
  I don't have a good answer to your question other than "assume they are". And that's the best answer in my opinion. It's not just installing a cert on your machine that can MITM your SSL connection. Proxy servers can often terminate SSL connections and re-sign them before delivering the content to you as well. Just assume your workplace has the ability to monitor all of your activity on your work-owned computer, because whether they do or do not watch you, the capability for them to watch you does exist.
  - adrianpike 12y ago
    I definitely agree on that being the best answer - it's a pretty silly game to start playing to try and pull one over on an employer. :) That said, I do wish there was a tool I could use to verify the cert authorities installed on a device I own or buy. On the far end of the spectrum, I've purchased a sketchy Android tablet once from AliBaba - that was rife with oddness. Also - wouldn't a proxy terminating & then re-signing show up as a different signing authority or cert, assuming they didn't have their own authority installed on my machine?
  - deleted 12y ago
    [deleted]
- streptomycin 12y ago
  Install something that doesn't use your system's certs (I think cURL would suffice, I forget exactly) and see if it breaks when you use it on an https URL. If it does, you're being MITMed.
- tomjen3 12y ago
  Go to an SSL site and see who has signed the certificate. Then go to the same site on your smartphone (on 3G, not wifi) and see who has signed it. Are they different? Note, unless it is a company issued phone it should show the real certificate, but this method is only about 99% safe (in case you were tricked into install an incorrect certificate on your phone at some point).
  - dijit 12y ago
    now lets do that for all connections, all new site requests and all analytics tracking. I mean, you _can_ check it, 99% of people including myself will let it slip their mind.
  - ufmace 12y ago
    Anybody know how to see the full certificate chain for a website on Android? I just tried it, and it isn't clear if you can, and web and app searches don't seem to show anything useful.
- IgorPartola 12y ago
  Would anyone be interested in a site that lets you see who signed the web server's cert from different points on the Internet? Sort of like IsItUp.com but for MITM.
  - dijit 12y ago
    Convergence by Moxie Marlinspike does that. doesn't work terribly well in practice though. http://convergence.io/ http://convergence.io/
    - IgorPartola 12y ago
      Out of curiosity, why doesn't it work?
      - dijit 12y ago
        massive latency mostly. although there are a lot of issues[0] on it's github page which seem to be unaddressed. [0] - https://github.com/moxie0/Convergence/issues https://github.com/moxie0/Convergence/issues
  - toomuchtodo 12y ago
    https://www.grc.com/fingerprints.htm https://www.grc.com/fingerprints.htm
    - PhantomGremlin 12y ago
      That's a very good explanation of the general state of affairs. But in my experience trying the Certificate Patrol add-on for Firefox for a few months, the ideal of "the authentic site's fingerprint" doesn't exist for big sites. It works for small sites like grc.com, but larger sites constantly present a variety of certificates. That variety seems to change every few days. Also certificate expiration times frequently change. Gibson does acknowledge "False-Positive Mismatches" but in my experience this is a big big problem that makes the single "fingerprint" idea almost useless. A smart add-on would eliminate a lot of these false positives. E.g. if your browser has already stored a certificate for a site and the new certificate is issued by the same CA to the same entity and the only difference is a new expiration date, why not silently accept the new one, while still remembering the old expiration? That's a risk I'd be willing to take. Same thing for multiple certificates from different issuers. I want to be warned only the first time a certificate is encountered. If the same one is encountered again next week or next month, then that's another "false-positive mismatch" that should be silently suppressed. And, realistically, why does there need to be an add-on? Mozilla gets something like $300 million per year in funding. What are they doing with all that money, if Firefox is still so vulnerable to this nonsense?
unsignedint 12y ago
Well, as MITMing with their own SSL certs will give the telltale signal that the session is being MITMed. But I'm still with you on this one. They may not necessarily have traffic monitoring on the wire, but they may monitor computer usage in another way. (Through asset management softwares, etc.)
sigsergv 12y ago
You can monitor traffic without interception, just look for SNI extension part of SSL traffic and you'll obtain hostname (all modern browsers use SNI by default). So it's easy at least know what sites people visit.

by CHY872 12y ago

adrianpike 12y ago

What's an easy way to find out if they're doing this? Taking a look at the certs installed in my system, unless I see "BigCo MITM Cert", I don't have a ton of insight on what certs are and aren't supposed to be there. Also, I'm not 100% on where all certs would be found, and short of looking at the trust chain on each site I visit, I'm not actually sure how to know.

freehunter 12y ago
I don't have a good answer to your question other than "assume they are". And that's the best answer in my opinion. It's not just installing a cert on your machine that can MITM your SSL connection. Proxy servers can often terminate SSL connections and re-sign them before delivering the content to you as well. Just assume your workplace has the ability to monitor all of your activity on your work-owned computer, because whether they do or do not watch you, the capability for them to watch you does exist.
- adrianpike 12y ago
  I definitely agree on that being the best answer - it's a pretty silly game to start playing to try and pull one over on an employer. :) That said, I do wish there was a tool I could use to verify the cert authorities installed on a device I own or buy. On the far end of the spectrum, I've purchased a sketchy Android tablet once from AliBaba - that was rife with oddness. Also - wouldn't a proxy terminating & then re-signing show up as a different signing authority or cert, assuming they didn't have their own authority installed on my machine?
- deleted 12y ago
  [deleted]
streptomycin 12y ago
Install something that doesn't use your system's certs (I think cURL would suffice, I forget exactly) and see if it breaks when you use it on an https URL. If it does, you're being MITMed.
tomjen3 12y ago
Go to an SSL site and see who has signed the certificate. Then go to the same site on your smartphone (on 3G, not wifi) and see who has signed it. Are they different? Note, unless it is a company issued phone it should show the real certificate, but this method is only about 99% safe (in case you were tricked into install an incorrect certificate on your phone at some point).
- dijit 12y ago
  now lets do that for all connections, all new site requests and all analytics tracking. I mean, you _can_ check it, 99% of people including myself will let it slip their mind.
- ufmace 12y ago
  Anybody know how to see the full certificate chain for a website on Android? I just tried it, and it isn't clear if you can, and web and app searches don't seem to show anything useful.
IgorPartola 12y ago
Would anyone be interested in a site that lets you see who signed the web server's cert from different points on the Internet? Sort of like IsItUp.com but for MITM.
- dijit 12y ago
  Convergence by Moxie Marlinspike does that. doesn't work terribly well in practice though. http://convergence.io/ http://convergence.io/
  - IgorPartola 12y ago
    Out of curiosity, why doesn't it work?
    - dijit 12y ago
      massive latency mostly. although there are a lot of issues[0] on it's github page which seem to be unaddressed. [0] - https://github.com/moxie0/Convergence/issues https://github.com/moxie0/Convergence/issues
- toomuchtodo 12y ago
  https://www.grc.com/fingerprints.htm https://www.grc.com/fingerprints.htm
  - PhantomGremlin 12y ago
    That's a very good explanation of the general state of affairs. But in my experience trying the Certificate Patrol add-on for Firefox for a few months, the ideal of "the authentic site's fingerprint" doesn't exist for big sites. It works for small sites like grc.com, but larger sites constantly present a variety of certificates. That variety seems to change every few days. Also certificate expiration times frequently change. Gibson does acknowledge "False-Positive Mismatches" but in my experience this is a big big problem that makes the single "fingerprint" idea almost useless. A smart add-on would eliminate a lot of these false positives. E.g. if your browser has already stored a certificate for a site and the new certificate is issued by the same CA to the same entity and the only difference is a new expiration date, why not silently accept the new one, while still remembering the old expiration? That's a risk I'd be willing to take. Same thing for multiple certificates from different issuers. I want to be warned only the first time a certificate is encountered. If the same one is encountered again next week or next month, then that's another "false-positive mismatch" that should be silently suppressed. And, realistically, why does there need to be an add-on? Mozilla gets something like $300 million per year in funding. What are they doing with all that money, if Firefox is still so vulnerable to this nonsense?

unsignedint 12y ago

Well, as MITMing with their own SSL certs will give the telltale signal that the session is being MITMed. But I'm still with you on this one. They may not necessarily have traffic monitoring on the wire, but they may monitor computer usage in another way. (Through asset management softwares, etc.)

sigsergv 12y ago

You can monitor traffic without interception, just look for SNI extension part of SSL traffic and you'll obtain hostname (all modern browsers use SNI by default). So it's easy at least know what sites people visit.