Slashdot Mirror
Hackers Break Browser SSL/TLS Encryption
First time accepted submitter CaVp writes with an article in The Register about an exploit that appears to affect all browsers and can decrypt an active TLS session. From the article: "Researchers have discovered a serious weakness in virtually all websites protected by the secure sockets layer protocol that allows attackers to silently decrypt data that's passing between a webserver and an end-user browser."
A full disclosure is scheduled for Friday September 23rd at the Ekoparty conference. Note that this only affects SSL 2.0 and TLS 1.0; unfortunately, most web servers are misconfigured to still accept SSL 2.0, and TLS 1.1 and 1.2 have seen limited deployment. The practicality of the attack remains to be determined (for one, it isn't very fast — but if the intent is just to decrypt the data for later use, that isn't an impediment).
The attack can apparently be completed in about 5 minutes. That is plenty of time for attacking the average online banking session, never mind gmail and other sites that people log in to for hours at a time.
The attack appears to use javascript to push known plaintext over HTTPS to the web site before the actual login request is sent, so that the login credentials are transferred as part of a persistent SSL connection which now has a known IV. If this is correct, then the attack could be avoided by disabling persistent HTTPS connections in the browser. There is a performance cost to this, but I think most people would prefer to feel secure, and wouldn't really notice the extra costs of opening and closing individual HTTPS sessions for each browser request. Proxies might break that though.
Now we know what that 30,000 node EC2 cluster was for...
For one, /. works a lot better with javascript disabled.
Give me Classic Slashdot or give me death!
They can. Not only is Javascript injection possible, it has already been done by at least one malicious government: "Malicious code injected into Tunisian versions of Facebook, Gmail, and Yahoo! stole login credentials of users critical of the North African nation's authoritarian government, according to security experts and news reports."
Yeah, and see how many websites built in the last eight or nine years work without Javascript... Hell, for real security, go back to using Gopher!
As a happy noscript user I was about to reply similarly to VLM below...
But instead it prompted me to check how many entries are in my noscript whitelist after using the same firefox profile for a bit over 3 years, and there are only 275 entries, of which 80 are various internal IPs for work related webapps and testing/development (Which I really need to clean out)
I don't think it's too bad of a sign that in 3 years only 200 websites I've visited were 'broken' without javascript! I was actually expecting a much higher number.
Even with that 200, or lets include the internal webapp sites at work and say 300, with the number of websites I've visited over the past three years it has to be in the high four digits. That is a pretty awesome ratio!
Most websites really do not break enough to matter when rolling without javascript. Even in mitigating this type of attack, I would rather white list the few sites that need it than leave javascript blanket open to every website out there.
Of course this solution isn't 100% perfect (It's "only" mostly perfect), so it will no doubt get poopoo'ed here on slashdot for not being over 100% perfect in every way
No way man, this place is so much better with ja
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