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CryptoCat iOS Application Penetration Test [pdf]

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Re: CryptoCat iOS Application Penetration Test [pdf]

#121

Post by tptacek »

kaeporan wrote: post #115
rancor wrote: post #106

Earlier quoted context omitted.

And I agree, that's a bare minimum warning for all such software. I appreciate your efforts to make strong crypto more accessible to the general public. That being said, you and I both know that people are using Cryptocat in dangerous situations. And having worked on both medical imaging and secure messaging systems, I have a healthy respect for the consequences of implementation failure. As such, I feel that your di…

It's important to note that this audit was commissioned to evaluate a prototype build before release. It was expected to find bugs, and all bugs were fixed before release. I believe I take my job very seriously when I commission such audits on a bi-annual basis and transparently discuss the results. Independent individuals who find bugs (such as "Decryptocat") are also listened to and rewarded for their effort. I bel…

You keep saying "I commission the audits". Isn't OTF the one paying for these audits? Are you taking OTF grant money? If so, aren't you required to have the audits done?

Re: CryptoCat iOS Application Penetration Test [pdf]

#122

Post by danielweber »

kaeporan wrote: post #115
rancor wrote: post #106

Earlier quoted context omitted.

And I agree, that's a bare minimum warning for all such software. I appreciate your efforts to make strong crypto more accessible to the general public. That being said, you and I both know that people are using Cryptocat in dangerous situations. And having worked on both medical imaging and secure messaging systems, I have a healthy respect for the consequences of implementation failure. As such, I feel that your di…

It's important to note that this audit was commissioned to evaluate a prototype build before release. It was expected to find bugs, and all bugs were fixed before release. I believe I take my job very seriously when I commission such audits on a bi-annual basis and transparently discuss the results. Independent individuals who find bugs (such as "Decryptocat") are also listened to and rewarded for their effort. I bel…

> I've been having recurring suicidal thoughts for the past two years.

I urge you to talk with somebody.

Re: CryptoCat iOS Application Penetration Test [pdf]

#123

Post by kaeporan »

tptacek wrote: post #121
kaeporan wrote: post #115

Earlier quoted context omitted.

It's important to note that this audit was commissioned to evaluate a prototype build before release. It was expected to find bugs, and all bugs were fixed before release. I believe I take my job very seriously when I commission such audits on a bi-annual basis and transparently discuss the results. Independent individuals who find bugs (such as "Decryptocat") are also listened to and rewarded for their effort. I bel…

You keep saying "I commission the audits". Isn't OTF the one paying for these audits? Are you taking OTF grant money? If so, aren't you required to have the audits done?

I was the person who wrote to OTF asking them to fund our audit. I have no idea if they require it — I'm always the one to initiate the process.

Re: CryptoCat iOS Application Penetration Test [pdf]

#124

Post by kaeporan »

tptacek wrote: post #119
fit2rule wrote: post #118

Earlier quoted context omitted.

>What I'm curious about is, why don't other projects such as TextSecure publish their audits as well? Its embarrassing, duh.

For who, TextSecure or the auditors? Both are possibilities, one slightly more likely than the other. Auditors hate having reports published with no major findings.

Why isn't Moxie replying? Publishing an audit, with or without vulnerabilities, surely is beneficial to TextSecure. I don't understand their reticence to publish audits. We know OTF has commissioned at least two audits for them, but not a word has been heard about them.

In fact, OTF has actually complained about their projects choosing not to publish audits: https://www.opentechfund.org/article/bringing-openness-secur...

Re: CryptoCat iOS Application Penetration Test [pdf]

#125

Post by secfirstmd »

I for one think that Nadim and the Open Tech Fund are to be applauded for opening up their review to the public. I have to wonder how many other commercial and non-profit organisations would ever consider doing this? (Especially those which are in the field of communications and are relied on by people for their lives).

Many people on HN seem to be reading the review without actually looking at Nadim's response on the Cryptocat blog - which I urge everyone to read first before commenting.

https://blog.crypto.cat/2014/04/recent-audits-and-coming-imp...

As far as I understand the username for Nadim (Kaeporan) was also blocked from HN last night so probably he isn't able to continue responding to the comments up here.

Re: CryptoCat iOS Application Penetration Test [pdf]

#126

Post by tptacek »

kaeporan wrote: post #124
tptacek wrote: post #119

Earlier quoted context omitted.

For who, TextSecure or the auditors? Both are possibilities, one slightly more likely than the other. Auditors hate having reports published with no major findings.

Why isn't Moxie replying? Publishing an audit, with or without vulnerabilities, surely is beneficial to TextSecure. I don't understand their reticence to publish audits. We know OTF has commissioned at least two audits for them, but not a word has been heard about them. In fact, OTF has actually complained about their projects choosing not to publish audits: https://www.opentechfund.org/article/bringing-openness-secu…

This is the sixth time you've "asked" in this thread about TextSecure's audit. Cryptocat has literally never implemented a crypto feature of any sort, from random number generation all the way through user authentication, without some terrible vulnerability. TextSecure, on the other hand, is the subject of a total of zero published crypto vulnerabilities.

Whatever Moxie's reasons for not having published their audit, I'm sure they're valid. Either way, no amount of innuendo about TextSecure is going to change the ground truth about your own project.

There might be no person on the Internet more poorly positioned to cast aspersions on other people's projects than you. Please stop.

Re: CryptoCat iOS Application Penetration Test [pdf]

#127

Post by kaeporan »

tptacek wrote: post #126
kaeporan wrote: post #124

Earlier quoted context omitted.

Why isn't Moxie replying? Publishing an audit, with or without vulnerabilities, surely is beneficial to TextSecure. I don't understand their reticence to publish audits. We know OTF has commissioned at least two audits for them, but not a word has been heard about them. In fact, OTF has actually complained about their projects choosing not to publish audits: https://www.opentechfund.org/article/bringing-openness-secu…

This is the sixth time you've "asked" in this thread about TextSecure's audit. Cryptocat has literally never implemented a crypto feature of any sort, from random number generation all the way through user authentication, without some terrible vulnerability. TextSecure, on the other hand, is the subject of a total of zero published crypto vulnerabilities. Whatever Moxie's reasons for not having published their audit,…

To be clear, I'm not trying to cast aspersions. As I've already stated, TextSecure is a great project that I strongly recommend.

I'm trying to have a serious discussion regarding transparency of audits. I feel your reaction is overly aggressive and not genuinely constructive.

Re: CryptoCat iOS Application Penetration Test [pdf]

#128

Post by rancor »

kaeporan wrote: post #115
rancor wrote: post #106

Earlier quoted context omitted.

And I agree, that's a bare minimum warning for all such software. I appreciate your efforts to make strong crypto more accessible to the general public. That being said, you and I both know that people are using Cryptocat in dangerous situations. And having worked on both medical imaging and secure messaging systems, I have a healthy respect for the consequences of implementation failure. As such, I feel that your di…

It's important to note that this audit was commissioned to evaluate a prototype build before release. It was expected to find bugs, and all bugs were fixed before release. I believe I take my job very seriously when I commission such audits on a bi-annual basis and transparently discuss the results. Independent individuals who find bugs (such as "Decryptocat") are also listened to and rewarded for their effort. I bel…

I read the blog post reacting to this batch of audit results quite carefully, in point of fact. In general, when I read vendor responses to such devastating findings, I'm looking for a concrete plan to improve the threat modeling and development practices deficiencies which are inevitably the root cause of the class of issues uncovered by the iSec and Least Authority audits. Without such changes, saying that you're going to keep getting audited is precisely equivalent to saying that you're going to to keep writing security bugs and hope someone finds them before the actual red team owns you.

While I agree that the degree of openness your team has maintained is highly desirable, repeatedly shipping bugs which adherence to industry best practices such as "don't use fixed IVs" or "always use constant-time compares" would have avoided makes it difficult to believe that your team possesses the competence you claim as well as undermining the credibility of your communication about such issues. Thus my failure to be impressed by a post which only proposes band-aids and completely fails to apologize for the lapses in judgment which led to this state of affairs.

I don't take using this level of harshness in a public forum lightly, and I'm truly sorry to contribute to your unhappiness as a result. Please do talk to somebody, even if it's not a professional, I've found it always helps.

Re: CryptoCat iOS Application Penetration Test [pdf]

#129

Post by kaeporan »

rancor wrote: post #128
kaeporan wrote: post #115

Earlier quoted context omitted.

It's important to note that this audit was commissioned to evaluate a prototype build before release. It was expected to find bugs, and all bugs were fixed before release. I believe I take my job very seriously when I commission such audits on a bi-annual basis and transparently discuss the results. Independent individuals who find bugs (such as "Decryptocat") are also listened to and rewarded for their effort. I bel…

I read the blog post reacting to this batch of audit results quite carefully, in point of fact. In general, when I read vendor responses to such devastating findings, I'm looking for a concrete plan to improve the threat modeling and development practices deficiencies which are inevitably the root cause of the class of issues uncovered by the iSec and Least Authority audits. Without such changes, saying that you're g…

I disagree; I don't think your summary is accurate. This is an audit of a pre-release prototype. All the bugs were fixed before release, and our blog post at https://blog.crypto.cat/2014/04/recent-audits-and-coming-imp... does not discuss mere band-aids. It discusses, at length, real solutions to complex problems that many encryption apps face. It resolves pitfalls that even companies like Apple commit on a much wider scale and on a much more dangerous level.

For example. We didn't simply "re-use fixed IVs". We know not to do that. The resulting bug was the series of a much more complicated and hard to spot issue with the re-keying mechanism. Understand you might not have the full picture here.

Simply put, I refuse the assertion that Cryptocat's team has not dealt with its software development in a competent, professional, responsible and honest fashion.

I want to discuss this further with you. I want to convince you of my point of view. Please email me at nadim@nadim.cc so I can have the opportunity to discuss with you and hopefully convince that your perspective isn't exactly right on this.

Re: CryptoCat iOS Application Penetration Test [pdf]

#130

Post by diminoten »

marshray wrote: post #112
diminoten wrote: post #111

Earlier quoted context omitted.

You lampoon yourself with this extremist attitude.

Go read http://tobtu.com/decryptocat.php and earlier sources before deciding he's being extremist.

I have, and I still believe he's being extremist. No one is in this space unscathed. For no other product have I seen the same level of vitriol and hate being spit at Cryptocat, despite it being absolutely not the only entrant.
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