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Re:Critical SSH Backdoor in multiple Barracuda Networks Prod... by rdl on Thursday January 24, 2013 @01:49PM (#5111311)
Looks like it's worth avoiding Barracuda appliances even after this patch, since they're retaining the "remote" account.

As to why they did this -- feature checklist compatibility with Huawei and ZTE is my guess.

Remember most of these do intercept -- they have an SSL CA cert which is trusted by all your business client devices, to do MITM. So, if you pwn the box, you can pwn all the SSL traffic at the target company, too. It's an excellent place to attack.

Re:Critical SSH Backdoor in multiple Barracuda Networks Prod... by tptacek on Thursday January 24, 2013 @05:33PM (#5112721)
In reality, the CA=YES cert loaded onto a Barracuda MITM proxy at an enterprise would be a second-tier trophy in the biennial internal network penetration test.

Internal netpens for F-500 companies are often (maybe usually) considered failures for the pentest team if they don't yield mass server compromises from an unprivileged starting point.

If you can log into a middlebox like a MITM proxy from the Internet at all, you now have an Internet to internal-network pivot. You are at the "unprivileged starting point" of an internal net pentest. Go ahead and grab the CA=YES cert, but then get on with owning up the whole network.

Internal network security at large enterprise networks (the kinds that routinely MITM intercept SSL traffic) is extremely bad.

Re:Critical SSH Backdoor in multiple Barracuda Networks Prod... by atamyrat on Thursday January 24, 2013 @02:31PM (#5111612)
> Remember most of these do intercept -- they have an SSL CA cert which is trusted by all your business client devices, to do MITM. So, if you pwn the box, you can pwn all the SSL traffic at the target company, too. It's an excellent place to attack.

I really hope this certificate is not installed/trusted by default on major browsers. Can somebody confirm it?

EDIT:

https://www.barracudanetworks.com/news/press_release/33

"Transparent deployment of this enhanced SSL Inspection feature requires deployment of a trusted root certificate on client Web browsers."

Re:Critical SSH Backdoor in multiple Barracuda Networks Prod... by lawnchair_larry on Thursday January 24, 2013 @02:37PM (#5111644)
No, the way these work is your IT deploys the internal CA cert as trusted on all systems in the enterprise.
Re:Critical SSH Backdoor in multiple Barracuda Networks Prod... by alistair77 on Thursday January 24, 2013 @04:00PM (#5112175)
I believe IE and Chrome use the operating systems list of certs. So your corporate IT dept can deploy the trusted certificates pretty easily. Firefox has it's own list of certificates so in theory is less susceptible to these corporate MITM attacks.
Re:Critical SSH Backdoor in multiple Barracuda Networks Prod... by jlgaddis on Thursday January 24, 2013 @02:14PM (#5111491)
Wait, so is the private key for that certificate stored on the Barracuda device!?

If it's possible to become root on these devices, then ... wow.

Re:Critical SSH Backdoor in multiple Barracuda Networks Prod... by tedunangst on Thursday January 24, 2013 @02:25PM (#5111559)
Yes, it has to be able to sign all the fake certs it generates.
Re:Critical SSH Backdoor in multiple Barracuda Networks Prod... by lawnchair_larry on Thursday January 24, 2013 @02:39PM (#5111664)
No, he means the ssh key.

Edit: Nevermind, he doesn't...I thought that's what "become root" meant.

There are ssh pub keys on it, so anyone with the private key can log in. I believe F5 networks had appliances with this problem, and the corresponding ssh private key was also left on the device.

Re:Critical SSH Backdoor in multiple Barracuda Networks Prod... by jlgaddis on Thursday January 24, 2013 @02:30PM (#5111603)
Seems like it would be possible to extract the private key then and use it elsewhere, no? So you wouldn't be limited to MITM'ing only at the company where this device sits, but you could effectively MITM (without generating any certificate errors or warnings) anywhere you can get in between the client and server?

Or am I missing something?

Re:Critical SSH Backdoor in multiple Barracuda Networks Prod... by bri3d on Thursday January 24, 2013 @02:50PM (#5111754)
You're missing something.

These aren't certificates signed by a CA that's trusted by most browsers - they're self-signed certificates (signed by the appliance) that are trusted within the organization using the Barracuda hardware by provisioning employee browsers to accept the CA.

If you were to extract the private key and use it to sign certificates elsewhere, you'd get the same warning as though you generated a random certificate and used it; the key is only useful within the organization that trusts it.

Re:Critical SSH Backdoor in multiple Barracuda Networks Prod... by btown on Thursday January 24, 2013 @06:55PM (#5113066)
For a large enough organization, this could be enough. Would it be possible for a hacker to break in, extract the private key, cover their tracks, then create, say, a phishing website that uses the Barracuda CA? Would it show up as a self-signed certificate at any other organization, but it would show up as a trusted site within the organization?
Re:Critical SSH Backdoor in multiple Barracuda Networks Prod... by jlgaddis on Thursday January 24, 2013 @09:37PM (#5113615)
Okay, I understood it as the CA certificate was signed by a "trusted" root CA (one already present/trusted by user's browsers). Glad to hear I'm wrong. Thanks.
Re:Critical SSH Backdoor in multiple Barracuda Networks Prod... by marshray on Thursday January 24, 2013 @02:48PM (#5111737)
The Barracuda device doesn't allow you to do anything you couldn't already do with other tools.

However, if an organization were able to get a widely-trusted MitM cert (such as this one http://www.theregister.co.uk/2012/02/09/tustwave_disavows_mi... or this one http://ssl.entrust.net/blog/?p=1696 ) and deployed it on their Barracuda, it could likely be extracted by someone with root-level access.

It wouldn't surprise me to see some "loose nukes" arise out of Barracuda's utterly irresponsible behavior here.

Re:Critical SSH Backdoor in multiple Barracuda Networks Prod... by rdl on Thursday January 24, 2013 @02:56PM (#5111798)
A lot of companies do org-wide MITM CA keys, so just hitting one Barracuda box, stealing the CA key, etc. lets you attack all of that organization's users everywhere.

Generally if you're targeting a specific organization, that's what you care about, anyway. You're not hacking into random companies to build a botnet; you're going after a specific organization to gain some economic or intelligence/military benefit.

I don't know what important organizations use Barracuda, though. It's generally SME-focused. Might be some interesting law firms and other organizations with sensitive data belonging to larger organizations, though.

Re:Critical SSH Backdoor in multiple Barracuda Networks Prod... by im3w1l on Thursday January 24, 2013 @04:05PM (#5112205)
If one were to get a widely-used SSL-cert, that could be used to MitM any domain ? Or would it only work for specific domains like, this one works for Google and Yahoo, but this one would work for Microsoft?
Re:Critical SSH Backdoor in multiple Barracuda Networks Prod... by marshray on Thursday January 24, 2013 @04:40PM (#5112428)
There are two types of sub-CAs that we could see leak from interception devices that chain to a widely-trusted root:

1. Unconstrained, like the Trustwave and Turktrust examples. These can be used to MitM any domain, with a very few exceptions like Chrome talking to Gmail. This is the normal kind of subCA.

2. Name-constrained sub-CAs such as described here https://groups.google.com/forum/?fromgroups=#!topic/mozilla.... These are very new. They aresupposed to be for organizations (say example.com) that want to issue their certs for www.example.com, intranet.corp.example.com, and so on without using a wildcard cert or paying extra for every single cert.

Neverheless, these private keys can sign MitM certs for any domain, however, whether or not it's valid is in the mind of the client application. Recent versions of the the three major browsers should in theory only accept them for names that sub-CA is approved for. But few if any non-browser SSL/TLS clients recognize these name constraints, so it represents full MitM capable attacker to those clients. Of course, there are a lot of TLS clients that don't validate or even check the subject name on the server cert at all, so many of these apps are pwned anyway.

Re:Critical SSH Backdoor in multiple Barracuda Networks Prod... by tedunangst on Thursday January 24, 2013 @04:33PM (#5112379)
If you have a signing cert that browsers trust, you can forge a cert for any site (unless your browser has previous knowledge and pinned the right cert for a site).