Microsoft Warns Customers Away From RC4 and SHA-1
Trailrunner7 writes "The RC4 and SHA-1 algorithms have taken a lot of hits in recent years, with new attacks popping up on a regular basis. Many security experts and cryptographers have been recommending that vendors begin phasing the two out, and Microsoft on Tuesday said it is now recommending to developers that they deprecate RC4 and stop using the SHA-1 hash algorithm. RC4 is among the older stream cipher suites in use today, and there have been a number of practical attacks against it, including plaintext-recovery attacks. The improvements in computing power have made many of these attacks more feasible for attackers, and so Microsoft is telling developers to drop RC4 from their applications. The company also said that as of January 2016 it will no longer will validate any code signing or root certificate that uses SHA-1."
Why in gods name would a company that backdoored their entire crypto stack to the NSA worry that
some crypto code is weak?
Sig Battery depleted. Reverting to safe mode.
Its not just the codes used, its the US branded: OS, file systems, "bugs" and files sent.
Domestic spying is now "Benign Information Gathering"
Microsoft continues to make use of MD4 for password hashing in the Security Account Management part of the registry. The authors of MD4, RSA, had recommended for a long time switching to MD5 and now recommends using MD6, Other members of the security community also recommend using a stronger hash function, combining a salt string with the password and doing multiple rounds of the hash function. Microsoft has failed to do any of these recommendations.
MS-CHAPv2 also continues to be part of Microsoft's offering as well. Support for this is included in their OS for PPTP, iSCSI and 802.1x (and possibly others). As pointed out in the article, attacking MS-CHAPv2 is now as simple as cracking a single DES key.
It is nice the Microsoft is recognizing some of the advice of the security community and taking steps to phase out SHA-1 and RC4. But I have a hard time applauding Microsoft when this is just the tip of the iceberg of weak hashing functions and protocols in popular use in their software.
Because the NSA doesn't like when someone else can get your files.
It slows them down.
... what do we replace all our database password hash columns with now?
Because although they gave it the NSA, they still don't want the Chinese government to compromise it?
Just because you're paranoid doesn't mean there isn't an invisible demon about to eat your face
Because... the NSA pays MS for backdoors, whereas the Russians don't?
Because... the NSA tries to stay under the radar, whereas other malware often doesn't? (ex. adware, bot-nets. Thus damaging the MS "experience".)
Because... the NSA wants to know your secrets, whereas scammers want to use your secrets? (ex. Credit card payments. Further damaging the MS "experience".)
Just a few thoughts.
MD5 is broken, SHA1 has been weakened slightly but it isn't broken.
The term broken is only used when it is trivial to crack and/or forge.
There's trolling, and then there's trolling on drugs that only got invented last week. Damn dude, whatever that new stuff is, it's no good for you.
Write failed: Broken pipe
No more RC4? No more SHA1? Next they'll be telling me to patch against WMF exploits.
Thank God we can still depend on ActiveX!
#DeleteChrome
MD5 is broken, SHA1 has been weakened slightly but it isn't broken. The term broken is only used when it is trivial to crack and/or forge.
Sorry to nitpick it really depends on how you use the algorithm. MD5 is broke for signatures yet still perfectly acceptable for other purposes.
Plenty of time between now and January 2016 when MS will reject the use of SHA1. I understand that large corporations move slowly, but we have known about SHA1 shortcomings for a while now. I would like to read more about what products are affected, possible attacks in product contexts, and reasons for the long window until retirement! Even Windows 7 mainstream support will end in 2015!
Why in gods name would a company that backdoored their entire crypto stack to the NSA worry that some crypto code is weak?
Because they now have a better back door that needs to become the default.
Why? Because the attacks on RC4 are becoming feasible for ordinary well-organized criminals, and there might be other agencies aside form the NSA who might try brute-forcing SHA1.
The NSA is mainly a danger for business outside the US - and perhaps for Megaupload-like companies within the US for which some state prosecutor could imagine and construct some criminal copyright infringement case, although it seems that the NSA doesn't habitually help out the FBI.
That's not the definition of "broken" that cryptographers use.
I can understand RC4.
I can understand MD5.
But SHA1? right now, according to wikipedia, a full collision attack requires something like $2.77M of computing power on the cloud...
maybe a less if you have you own supercomputer, but even at $1M it sound a lot...
So why warn away from SHA1 NOW? what are we going to use? md5? md4? remember that while keccak was chosen as the SHA3, they still have to release the complete details on how it must be implemented -- number of rounds and such -- so SHA3 *NOW* is not an option.
I'll start taking microsoft seriously on this once they phase out MD4, RC4, MD5 from their existing standards and products.
"I was gratified to be able to answer promptly, and I did. I said I didn't know." -- Mark Twain
Why does the NSA want to know my secrets if they are not going to use it?
MD5 is broken, SHA1 has been weakened slightly but it isn't broken.
Same for RC4. The cypher is still OK, you just have to initialize it better (his has been known about for decades, the fact that Microsoft isn't doing it is the real news).
No sig today...
Just plain wrong.
In the field of cryptography, the term "broken" is used whenever the work factor to crack is less than that of a brute force attack. Stevens' 2^61 collision attack against SHA1 means that SHA1 is broken.
Also FatPhil on SoylentNews, id 863
We have a real problem where the PCI scanning vendors are so freaked out about BEAST attacks (where client hardening is the correct solution) that the only cipher they'll accept (server side) that's FIPS compliant and BEAST resistant is RC4.
What they should be doing instead is scoring people down for not doing ephemeral key exchange, scoring people down for not using TLS 1.2 and stop freaking out about CBC on the server side when getting rid of it is not even a thorough solution (fear of CBC is overblown, especially when compared to post-Snowden risks).
If you look at your ciphers, even if you're negotiating ephemeral ECC with Google, you're then using RC4 as your stream cipher. RC4 isn't _so_ horrible that this is a major risk, but it's a theoretical one and it might fall eventually. Ephemeral key exchange is there to prevent against future attacks on captured streams, so RC4 may not be the best pairing for that.
So, perhaps Microsoft is doing a good thing here and putting its weight behind some pressure to move past RC4.
My God, it's Full of Source!
OUTSIDE_IP=$(dig +short my.ip @outsideip.net)
If that was true then pretty much every widely-used crypto system (AES, RSA, El Gamal, etc) would be "broken".
They don't admit to helping the FBI. Look up 'parallel construction.'
Specifically, you "just" need to discard the first n bits of the keystream, and n seems to get larger every year. Do excuse me if that doesn't inspire confidence.
Look, if you absolutely need to support some legacy application that only speaks RC4, that's one thing, but there's no reason beyond that to choose it over AES-256-GCM these days.
SHA-2, more specifically its SHA256 ^2 variant, is not only used to secure messages in HMAC, but also in bitcoin for validating blocks (adding pages into the common distributed ledger), and thus also in bitcoin mining.
Given the current massive craze in bitcoin, there's been massive development around SAH256.
If SHA256 was cracked, somebody would be laughing on the way to the bank, after having mined most of the coin.
That didn't happen (current bitcoin production is still spread among the most popular mining pools, there's no single individual significantly faster than everybody else)
that's a good sign that SHA-2 won't be cracked in the near future despite how much resources the NSA, FSB and Co put at it.
"Sufficiently advanced satire is indistinguishable from reality." - [Tips: 1DrYakQDKCQ6y52z6QbnkxHXAocMZJE61o ]
Git is a great system, but it relies on SHA1. If SHA1 has feasible attacks, is git going to stay on SHA1 or will it move to something more secure? Can it even do so without breaking compatibility?
Dangerous, sexy, turing complete: Femme Bots
RC4 is NOT FIPS compliant. Never has been. RSA has never published a spec for RC4. The code just showed up one day on a mailing list from an anonymous source.
There is no faster than brute force attack for AES, unless you modify the algorithm to have less rounds but then it's no longer AES.
MD5 is broken, SHA1 has been weakened slightly but it isn't broken. The term broken is only used when it is trivial to crack and/or forge.
Sorry to nitpick it really depends on how you use the algorithm. MD5 is broke for signatures yet still perfectly acceptable for other purposes.
This is true of anything. All statements about security are relevant only within a given set of threat models.
Note to ACs: I usually delete AC replies without reading them. If you want to talk to me, log in.
Or that we shouldn't use WEP for our wireless encryption.
AES is considered broken, but safe to keep using.
Sorry, forgot about that one. While it's true that AES is broken, the attack in question is currently quite impractical since it requires a 2^88 data space
They no longer deny helping the FBI, DEA, ATF, and county sheriffs.
Sig Battery depleted. Reverting to safe mode.
Because Microsoft doesn't deliberately open back doors for free.
[for BEAST] client hardening is the correct solution
Indeed. TLSv1.1 is not vulnerable, and most browsers that are still limited to TLSv1.0 are able to use the 1/n-1 split workaround to BEAST (notable exception is Safari on MacOS up to X.8). The right approach would be to detect TLSv1.0 clients that do not use 1/n-1 split and deny them access before they exchange anything sensible.