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I was interested to lookup the traffic of an app and I installed MITM-proxy on my Mac and set up the connection to it on my iPhone.

Actually everything worked like it should, except that the main functions are kind of "blocked" when I try to use them in the app. But when I leave the proxy e.g. turn off my wifi, the app works like it should.

At work we are using a proxy too, but the app works there without problems. How can the app detect the MITM-proxy and is there a way to get around it?

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This is likely due to the fact that the certificates used by the apps are pinned. This way breaking the TLS connection with a proxy fails.

It works in your company because the traffic is proxied, but not decrypted/reencrypted - the app does a direct CONNECT call to its server.

  • As far as I know I have to accept a certificate when I'm trying to use the wifi at work. Because of that I guess it decrypts all requests. Is there a way to analyce the traffic even if the app pinnes the certificate? – Mr.Tr33 May 3 '17 at 14:23
  • @Mr.Tr33: checking whether data is decrypted is easy: just have a look at the certificate when connecting to an HTTPS site. You will see the proxy cert and not the destination one. As for how to analyze the traffic in that case: I do not know any way, the idea behind pinning is for that exact reason: to ensure that you have an uninterrupted connection to the server from your app/browser, without a MitM. – WoJ May 3 '17 at 14:31
  • @Mr.Tr33: as a side note, some browsers may disable pinning when the certificate chain is private - to exactly enable "corporate-approved MitM". The certificate will still be the one of your company and not the target one, though. – WoJ May 3 '17 at 14:35
  • You had to accept a certificate at work most likely because you have RADIUS auth on your wifi. Do you need a username/password to sign in to the wifi? – Sirens Oct 31 '17 at 1:49

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