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Zimbra Desktop Vulnerable to Man-in-the-Middle Attack
tiffanydanica writes "For all the flack Mozilla gets about its new security warnings for https sites, at least it warns the user when a mismatch occurs. Sadly the new Yahoo! Zimbra Desktop (released in part to fix some security issues), doesn't bother validating the SSL certificate on the other side before sending along the username and password, making it vulnerable to a man-in-the-middle attack. This is certainly a step up from transmitting the information in the clear, since the attacker must switch from being passive to active, but with all of the DNS security problems, it would be fairly trivial for a malicious attacker to grab a large number of Yahoo! accounts (be it for phishing or spaming). Hopefully this issue will get fixed shortly, but for now Yahoo! Zimbra Desktop users may wish to use the webmail interface."
Since BT is giving Phorm a MitM position in their network, does this mean that Phorm would be able to read the email of anyone that uses Yahoo Zimbra, even if they try to use https?
If I have nothing to hide, don't search me
So a man in the middle would decompile the program, change the address it goes to, then recompile it, and that's going to be stopped if it used HTTPS?
I do realise man-in-the-middle attacks are possible. But what you described certainly isn't one.
As aussie_a said, what you describe is in no way similar to a man-in-the-middle attack. 'MITM' refers to be the ability to eavesdrop on and forge network traffic. Fake login pages is part of 'phishing'.
http://en.wikipedia.org/wiki/Man-in-the-middle_attack
http://en.wikipedia.org/wiki/Phishing
How do you just jump in the middle of someone's connection?
There are a number of ways to do it. You can:
There are probably a few other ways to do it, but that's all off the top of my head.
I hereby place the above post in the public domain.
Firefox gets criticised for its new warnings because:
1. The old mis-match warnings were just fine unless the user doesn't read warnings, in which case the new ones won't help anyway.
If you want to work around the certificate error, you more or less have to read the text. Arbitrarily clicking the "go away" button does not do what you would expect. Even once you choose to add an exception, you have to manually press a button to choose to download the certificate, and THEN enable the exception.
2. They look like errors. They're not errors, they're warnings.
A bad SSL certificate is an error. These types of rationalization are simply born of outright laziness coupled with gross ineptitude.
3. Why can't it just present the page as insecure (no padlock) by default?
It would still say 'https'. Why can't administrators just use non-broken certificates?
2. They look like errors. They're not errors, they're warnings.
A bad SSL certificate is an error. These types of rationalization are simply born of outright laziness coupled with gross ineptitude.
Especially since you can even get free ssl certificates from people like http://www.startssl.com/?app=1
Firefox gets criticised for its new warnings because:
1. The old mis-match warnings were just fine unless the user doesn't read warnings, in which case the new ones won't help anyway.
2. They look like errors. They're not errors, they're warnings.
You can't have it both ways - those two points are contradictory. If they look like an error, then someone who doesn't read them will think they're an error and stop - they'll hit the Home button or whatever. That saved the non-warning-reader from being phished.
3. Why can't it just present the page as insecure (no padlock) by default?
Because it's not a big enough clue that you're being attacked by an active man-in-the-middle (e.g. Kaminsky DNS attack). People will miss it - after all, they went to their bank via their bookmark as usual, they're expecting it to be secure. You want a big full-screen "you are being hacked!" warning.
You have to give the vendor at least a chance to get the bug fixed.
No, you don't. For all we know, some black-hat hacker may have already found this vulnerability and be actively exploiting it.
It's the same old discussion every time. There are arguments for and against releasing vulnerabilities without notifying the vendor in advance, I know, but from a developer's standpoint (and from a user's), it's preferrable to give at least a grace period before releasing the details.
The advantages of releasing immediately are:
The disadvantages are:
In this specific case, the Zimbra users are definitely worse off, unless they happen to read Holden Karau's blog (or Slashdot).
But maybe Holden will get his t-shirt now, so that's ok.
CJ
Ah, arrogance and stupidity, all in the same package. How efficient of you. -- Londo Mollari
"At the time of the writing Yahoo! security has been notified."
I do wonder what route he chose to notify them? Maybe an email to postmaster@... ?
I don't see anything on Zimbra's bugzilla which I'd have thought would be the proper place to make such a report.
Maybe that was too difficult to find, and wouldn't be immediately obvious to other zimbra users. But then there's nothing immediately obvious on the official zimbra forums either.
Most proxies just forward HTTPS traffic because they can't do anything else (they can't read the contents of the messages!).
Technically you could verify the authenticity of the public key proposed by the host (or MitM) because IIRC at that point the communication isn't encrypted yet, but I don't know if there's personal proxying software that can do this.
My english is sow-sow. Sowhat?