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I wasn't going to post this, but I had the same feeling at a conference. Also, if I remember correctly, the first version that got audited turned out to be extr

I wasn't going to post this, but I had the same feeling at a conference. Also, if I remember correctly, the first version that got audited turned out to be extremely insecure as well, with their own custom crypto protocols? I haven't recommended CryptoCat to anyone since, and still wouldn't. This audit report is another fascinating read to see all the mistakes I would probably have made as well. Secure crypto is so incredibly difficult to get right...

kaeporan 12y ago
It's important to note that this audit concerned a pre-release, debugging version of Cryptocat for iPhone. The audit document alone doesn't give enough context; I strongly urge reading our blog post: https://blog.crypto.cat/2014/04/recent-audits-and-coming-improvements/ https://blog.crypto.cat/2014/04/recent-audits-and-coming-imp...
- tptacek 12y ago
  Are you saying that it's good news because it means that no actual users were exposed to the flaws? To the extent that those flaws apply only to the iOS version, I agree: that's good news. Are you saying that it's good news because they tested something that you weren't ever going to release in that state? That's a tougher row to hoe, unless you're going to claim that your team inevitably would have found the same set of vulnerabilities that Scott, David, Alban, and Zooko's team found. For a typical application --- yours isn't typical for any number of reasons --- prerelease or not, the state the application is in when a pentest team gets it is, from the perspective of security, the application customers would have received.
  - zooko_LeastAuth 12y ago
    Speaking of the vulnerabilities that our team found, here is our blog post about it and a link to our report and the github issue tickets that we opened: Here is our blog post about our audit of Cryptocat, which was also announced today: https://leastauthority.com/blog/ https://leastauthority.com/blog/
    - tptacek 12y ago
      There is great stuff in here, including the CTR nonce reuse bug that Nadim wrote about earlier. Ouch.
      - zooko 12y ago
        Thanks! I'm very proud of our work in this audit.

kaeporan 12y ago

It's important to note that this audit concerned a pre-release, debugging version of Cryptocat for iPhone. The audit document alone doesn't give enough context; I strongly urge reading our blog post: https://blog.crypto.cat/2014/04/recent-audits-and-coming-improvements/ https://blog.crypto.cat/2014/04/recent-audits-and-coming-imp...

tptacek 12y ago
Are you saying that it's good news because it means that no actual users were exposed to the flaws? To the extent that those flaws apply only to the iOS version, I agree: that's good news. Are you saying that it's good news because they tested something that you weren't ever going to release in that state? That's a tougher row to hoe, unless you're going to claim that your team inevitably would have found the same set of vulnerabilities that Scott, David, Alban, and Zooko's team found. For a typical application --- yours isn't typical for any number of reasons --- prerelease or not, the state the application is in when a pentest team gets it is, from the perspective of security, the application customers would have received.
- zooko_LeastAuth 12y ago
  Speaking of the vulnerabilities that our team found, here is our blog post about it and a link to our report and the github issue tickets that we opened: Here is our blog post about our audit of Cryptocat, which was also announced today: https://leastauthority.com/blog/ https://leastauthority.com/blog/
  - tptacek 12y ago
    There is great stuff in here, including the CTR nonce reuse bug that Nadim wrote about earlier. Ouch.
    - zooko 12y ago
      Thanks! I'm very proud of our work in this audit.