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by rst 4918 days ago
Different vuln; this one has nothing to do with session cookies.
1 comments
jroes 4918 days ago
tenderlove mentions it has been assigned CVE-2012-5664. This is that CVE:

http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-5664

It references two articles that require session secrets.

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tenderlove 4918 days ago
Yes, the article does mention session secrets. However, this exploit does not require session secrets. The person who wrote the blog post wrote about essentially two vulnerabilities: session forging and SQL injection.
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Xylakant 4918 days ago
No, the guy showed a way to to sql injections by using a forged session. The problem is that the sql injection requires a hash with symbols as key and params are stored in HashWithIndifferentAccess which should not symbolize the keys. So to exploit the SQL injection you need a vector that allows you to inject symbolized keys. It might be possible to corrupt the params hash, but I can't think of any at the moment. However, the session can contain any ruby object and thus is a possible vector.
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cheald 4918 days ago
I'm pretty sure that the injection only works when you can forge a session because sessions may contain marshalled symbols, and the dynamic finders only accepted symbol option keys as valid. You can't get Rails to construct symbols out of a params hash. Is this a separate vulnerability?
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tptacek 4918 days ago
You can get Rails to construct symbols out of a params hash in some cases.
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cheald 4918 days ago
Seconding icambron - how? Because I've been up and down that code and can't see any way to do it. Frankly, I don't think it's possible, because otherwise you would have a trivial DOS vector into any Rails application.
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tptacek 4918 days ago
It is possible, but not straightforwardly. There isn't a code path I know of that converts param keys to symbols.

(I wouldn't have said it was possible unless I had a curl line that did it, for what it's worth.)

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ufo 4918 days ago
How is this a DOS vector? Would passing a symbol instead of a string in the parameters cause the app to crash?
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icambron 4918 days ago
Honest question: how?
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kill9 4918 days ago
I doubt tptacek will publicly reveal ways to exploit this (or any) vulnerability.

EDIT Well... he might, but I've never seen him do it. He's a security professional, after all.

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