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'Logjam' Vulnerability Threatens Encrypted Connections
An anonymous reader writes: A team of security researchers has revealed a new encryption vulnerability called 'Logjam,' which is the result of a flaw in the TLS protocol used to create encrypted connections. It affects servers supporting the Diffie-Hellman key exchange, and it's caused by export restrictions mandated by the U.S. government during the Clinton administration. "Attackers with the ability to monitor the connection between an end user and a Diffie-Hellman-enabled server that supports the export cipher can inject a special payload into the traffic that downgrades encrypted connections to use extremely weak 512-bit key material. Using precomputed data prepared ahead of time, the attackers can then deduce the encryption key negotiated between the two parties."
Internet Explorer is the only browser yet updated to block such an attack — patches for Chrome, Firefox, and Safari are expected soon. The researchers add, "Breaking the single, most common 1024-bit prime used by web servers would allow passive eavesdropping on connections to 18% of the Top 1 Million HTTPS domains. A second prime would allow passive decryption of connections to 66% of VPN servers and 26% of SSH servers. A close reading of published NSA leaks shows that the agency's attacks on VPNs are consistent with having achieved such a break." Here is their full technical report (PDF).
Internet Explorer is the only browser yet updated to block such an attack — patches for Chrome, Firefox, and Safari are expected soon. The researchers add, "Breaking the single, most common 1024-bit prime used by web servers would allow passive eavesdropping on connections to 18% of the Top 1 Million HTTPS domains. A second prime would allow passive decryption of connections to 66% of VPN servers and 26% of SSH servers. A close reading of published NSA leaks shows that the agency's attacks on VPNs are consistent with having achieved such a break." Here is their full technical report (PDF).
Really? The online JS test tells me my Iceweasel 38.0.1 isn't vulnerable.
"Good News! Your browser is safe against the Logjam attack. "
From TFA: "Generating primes with special properties can be computationally burdensome, so many implementations use fixed or standardized Diffie-Hellman parameters. "
Yeesh.
Reading is fundamental.
At the time these utterly stupid laws were made, these ciphers where still somewhat secure against most attackers. The problem is that encryption software and parameters can stay in use for a long time.
Most ACs are not even worth the keystrokes to insult them. Be generically insulted by this and ignored otherwise.
Did this flaw come into existance due to lazy programmers trying to save run time, or did the NSA install this as a back door? How badly has the NSA sabotauged the border defences of the USA?
oblig.
caused by export restrictions mandated by the U.S. government during the Clinton administration.
So this assertion arrives at one of two uncomfortable conclusions.
1. US intelligence agencies have had the ability to exploit this for more than a decade
2. US intelligence agencies, having understood advances in computing to be inevitable, carved a backdoor and did some wishful thinking.
Either way the internet is starting to realize not all well-intentioned backward compatibility that also includes an unfortunate downgrade in security is done in altruistic or neutral capacity. Shell companies and paid researchers can and have in the past intentionally rendered well constructed algorythms and crypto effectively optional in the name of compatibility and their product. Ephemeral ECC for example, although cited by reseachers as a means to avoid this kind of attack, is suspect. The NIST elliptic curves have now been tainted by Snowdens revelations as well. the SSH 2 implementation of the 25519 curve, by Aris of the libssh project, attempts to address the problem of divergences in elliptic-curve cryptography by proposing a safer alternative that doesnâ(TM)t implement the mysterious constants common among other schemes.
Good people go to bed earlier.
Too bad FireFox doesn't update the ESR versions of the past anymore. Yeah, I think you know where I'm going with this comment. Just go ahead and mod me down as a troll. But FireFox broke functionality with certain versions, so I'm sticking with what I have.
I'm sure some servers use export grade ciphers, but are any servers required to anymore?
The name of the article is virtually incomprehensible due to this shit. How about the original idea about saying a new TLS vulnerability? Would it be so fucking difficult? Yeah, mod me down.
will someday learn to live on her allowance, which is ample...
It means the have 10 new holes from Obama Administration...
With the PGP code, which was technically a "Controlled Munition"
Good times.
... and here's the breakdown:
IE and Safari test OK.
Firefox, Chrome, and Opera fail the test.
--
That's on my HP desktop at home.
It little behooves the best of us to comment on the rest of us.
There have been a couple of recent developments which attempt to fight back against the "CA coercion" vulnerability.
One is "http key pinning", that way your browser is still trusting the public CA network for the initial connection to a site but after that it additionally checks a list of keys provided by the site (the site has the option of whether to declare trust in a CA or whether to approve individual keys). This will make it very difficult for a MITM with a coerced key to operate in secret, if the user ever uses an internet connection the MITM doesn't control and then comes back to the one controlled by the MITM then they will notice the interference.
Another is "certificate transparency" which if enforced means a CA can't issue certs without publishing the fact they are doing so. This is a bit of a longer term goal, it will be some time if ever before clients can force this model on all CAs but again it will make it much easier to discover MITM attacks.
note: i'm known as plugwash most places but i screwd up registering that here somehow in the past and now can't register
There was an article about a month ago on /. talking about a researcher who wondered how many sites had already been patched against this vulnerability and when he started scanning, he found hundreds of thousands of hosts on the Internet that all use the exact same keys. A result of lazy router manufacturers preconfiguring them with standard keys instead of having the end user generate a new one.
Yet Australia wants to return to "export-grade" encryption.
Don Draper is busy writing copy for these vulnerabilities. Seriously, why are pathetic neckbeards the world over so obsessed with making these cute vulnerability names and logos? Since when did a security vulnerability need branding? I guess a CVE ID is unwieldly but when will the madness end? Is the next one going to be called FailPwn1012?
How long before legislators and the White House understand that this kind of restrictive export law simply handicaps US researchers and corporations? Competitors from other nations such as India and Russia get a significant advantage over their opposite numbers in the, er, Land of the Free.
I am sure that there are many other solipsists out there.
"Hello, meine dispatcher says there eez somezing wrong mit deine Encrypted Connections?"
"Yeah, come on in. I'm not really sure exactly what's really wrong with the cable."
"That's why they sent me, I am an expert."
Slow Down Cowboy! It's been 1 hour, 47 minutes since you last successfully posted a comment
Emilia from the OpenSSL team just published a good blog post that explains some of the "twists" of logjam, and also what OpenSSL is doing about it. It's here: http://openssl.org/blog/blog/2...
The Clinton Adminstration couldn't have been responsible for this cause it was Bush's fault.
Breaking the single, most common 1024-bit prime used by web servers
Well that's silly. They should try using different primes for a start.
systemd is Roko's Basilisk.
> Breaking the single, most common 1024-bit prime
What? Did we run out of primes? Why is everyone using the same prime?
Or am I misunderstanding the summary?
Math hurts my head.
CU
Kimberly
Encryption is a defensive technology, not a weapon.
I can't see any good reason (plenty of bad ones!) for ever limiting defensive technologies. Weapons are a different matter because they can cause direct harm to others, but a shield, or armour, or encryption, are all defense only with no offensive angle. They should never be limited.
I skimmed the start of the paper. If I have this right:
- Essentially all the currently-deployed web servers and modern browsers have the new, much better, encryption.
- Many current web servers and modern browsers support talking to legacy counterparts that only have the older, "export-grade", crypto, which this attack breaks handily.
- Such a server/browser pair can be convinced, by a man-in-the-middle who can modify traffic (or perhaps an eavesdropper-in-the-middle who can also inject forged packets) to agree to use the broken crypto - each being fooled into thinking the broken legacy method is the best that's available.
- When this happens, the browser doesn't mention it - and indicates the connection is secure.
Then they go on to comment that the characteristics of the NSA programs leaked by Snowden look like the NSA already had the paper's crack, or an equivalent, and have been using it regularly for years.
But, with a browser and a web server capable of better encryption technologies, forcing them down to export-grade LEAKS INFORMATION TO THEM that they're being monitored.
So IMHO, rather than JUST disabling the weak crypto, a nice browser feature would be the option for it to pretend it is unpatched and fooled, but put up a BIG, OBVIOUS, indication (like a watermark overlay) that the attack is happening (or it connected to an ancient, vulnerable, server):
- If only a handful of web sites trip the alarm, either they're using obsolete servers that need upgrading, or their traffic is being monitored by NSA or other spooks.
- If essentially ALL web sites trip the alarm, the browser user is being monitored by the NSA or other spooks.
The "tap detector" of fictional spy adventures becomes real, at least against this attack.
With this feature, a user under surveillance - by his country's spooks or internal security apparatus, other countries' spooks, identity thieves, corporate espionage operations, or what-have-you, could know he's being monitored, keep quiet about it, lie low for a while and/or find other channels for communication, appear to be squeaky-clean, and waste the tapper's time and resources for months.
Meanwhile, the NSA, or any other spy operation with this capability, would risk exposure to the surveilled time it uses it. A "silent alarm" when this capability is used could do more to rein in improper general surveillance than any amount of legislation and court decisions.
With open source browsers it should be possible to write a plugin to do this. So we need not wait for the browser maintainers to "fix the problem", and government interference with browser providers will fail. This can be done by ANYBODY with the tech savvy to build such a plugin. (Then, if they distribute it, we get into another spy-vs-spy game of "is this plugin really that function, or a sucker trap that does tapping while it purports to detect tapping?" Oops! The source is open...)
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
Mobile Safari, and the Apple Watch OS were updated yesterday.
... or a lot worse, vote for a Republican.
The US political system is completely screwed with only bad options left for the voters.
Most ACs are not even worth the keystrokes to insult them. Be generically insulted by this and ignored otherwise.
NSA owning VPNs is not surprising given pathetic state of VPN technology as currently deployed. Widespread use of group keys, PPTP and challenge response authentication. A tragedy of nonsense NSA would have to be negligently incompetent to not take full advantage of.
It isn't like this is a big secret or that people don't know better. The bells have been ringing for years ... dare I say decades in some cases yet many in a position to know better simply don't care.
What is interesting to me distance between EC and RSA in terms of relative key size vs security seems to be shrinking by quite a lot.
Honestly I never put much stock in differences between precomputation vs having to start over.
I know practically it makes it a lot easier to do a lot of damage but from my perspective if you have the resources to pull off something just once even if that effort can't be reused the technology has already failed.
I have not been able to quite figure out what they meant when they said TLS is broken. I understand the part of being able to negotiate parameters with a TLS extension yet at the end of the day if you are able to break lowest common denominator crypto so bad you can compromise handshake then secure negotiation must also cease to be secure.
There's nothing to understand; the summary is quoting confused idiots. Anyone who thinks a prime number can be "broken" doesn't know the first thing about cryptography.
Android was updated... Nevermind I can't afford a new phone.
This Sig does not Exist.
Thanks for summarizing what was already in the summary. Have a +5 Informative.