Do any browsers use CryptoAPI for TLS certificate validation?
Patch Critical Cryptographic Vulnerability in Microsoft Windows [pdf]
21–30 of 235 posts
Re: Patch Critical Cryptographic Vulnerability in Microsoft Windows [pdf]
#22None of these links describe how the exploit works.
I found this: https://media.defense.gov/2020/Jan/14/2002234275/-1/-1/0/CSA...
So based on my limited understanding:
1. The certificates have a place for defining curve parameters.
2. The attacker specifies their own parameters so that they match the start of a standard curve but choose the rest of the parameters themselves. With the right ECC math they are able to generate a valid signature for the certificate even though they don't own the private key corresponding to the original curve.
3. The old crypto API -didn't- check that certificates were signed from a fixed set of valid parameters. It would just check for sig validity allowing for spoofing of the cert.
Interesting stuff. So you might be able to cryptographically prove if there was ever any attacks in the wild from this at a given time (if we assume dates are checked at least)?
I wonder what happens at the Microsoft Security Response Center when a big vuln hits like this? Does it tie up all their resources just working on the one vuln?
Re: Patch Critical Cryptographic Vulnerability in Microsoft Windows [pdf]
#23Earlier quoted context omitted.
Not sure if you’re just being snarky, but the NSA’s stated mission includes helping with cyber security: https://www.nsa.gov/about/mission-values/
And what do you think the end state of all that cybersecurity research is?
NSA has long had an explicit offensive and defensive mandate. They even recently created a cyber defense directorate:
https://www.washingtonpost.com/national-security/nsa-launche...
Re: Patch Critical Cryptographic Vulnerability in Microsoft Windows [pdf]
#24At least this only affects Windows 10 (as far as I can tell)
Windows 7 reached EOL today so they may leave it as is if it is affected.
According to https://portal.msrc.microsoft.com/en-US/security-guidance/ad..., it doesn't look like windows 8.1 received a patch either, and that's still in support. Maybe only windows 10 has ECC support, and therefore any previous versions are not affected?
Also, according to https://support.microsoft.com/help/4534310, it looks like Windows 7 got security patches for this month.
Re: Patch Critical Cryptographic Vulnerability in Microsoft Windows [pdf]
#25None of these links describe how the exploit works. I found this: https://media.defense.gov/2020/Jan/14/2002234275/-1/-1/0/CSA... So based on my limited understanding: 1. The certificates have a place for defining curve parameters. 2. The attacker specifies their own parameters so that they match the start of a standard curve but choose the rest of the parameters themselves. With the right ECC math they are able to g…
Good find. This page should almost certainly be the headline article on HN, at least until someone does a full write-up of the vulnerability --- but the vulnerability here looks very simple (and gross): if you can define your own curve parameters and get CryptoAPI to honor them, you can sign anything.
Re: Patch Critical Cryptographic Vulnerability in Microsoft Windows [pdf]
#26Anyone got any news on Windows 7 seeing as it's still 25% market share approx according to statcounter?
Re: Patch Critical Cryptographic Vulnerability in Microsoft Windows [pdf]
#27Re: Patch Critical Cryptographic Vulnerability in Microsoft Windows [pdf]
#28From Krebs tweets: The NSA's Neuberger said this wasn't the first vulnerability the agency has reported to Microsoft, but it was the first one for which they accepted credit/attribution when MS asked. Sources say this disclosure from NSA is planned to be the first of many as part of a new initiative at NSA dubbed "Turn a New Leaf," aimed at making more of the agency's vulnerability research available to major softwar…
more like someone with some commonsense decided to capitalize on disclosing issues when other countries get zero days. Oh well, guess we can't use this anymore Bob, china has been exploiting it over the past week. Call Microsoft lets at least get some free PR in exchange of having to give this up.
Re: Patch Critical Cryptographic Vulnerability in Microsoft Windows [pdf]
#29None of these links describe how the exploit works. I found this: https://media.defense.gov/2020/Jan/14/2002234275/-1/-1/0/CSA... So based on my limited understanding: 1. The certificates have a place for defining curve parameters. 2. The attacker specifies their own parameters so that they match the start of a standard curve but choose the rest of the parameters themselves. With the right ECC math they are able to g…
Sounds similar to the post from a few days ago about the Firefox WebCrypto allowing too much adjustment of DH parameters: https://news.ycombinator.com/item?id=21980199
Re: Patch Critical Cryptographic Vulnerability in Microsoft Windows [pdf]
#30None of these links describe how the exploit works. I found this: https://media.defense.gov/2020/Jan/14/2002234275/-1/-1/0/CSA... So based on my limited understanding: 1. The certificates have a place for defining curve parameters. 2. The attacker specifies their own parameters so that they match the start of a standard curve but choose the rest of the parameters themselves. With the right ECC math they are able to g…
Sounds similar to the post from a few days ago about the Firefox WebCrypto allowing too much adjustment of DH parameters: https://news.ycombinator.com/item?id=21980199
It is indeed very similar in spirit, and of course much more devastating here.
Another attack, implemented on ECDSA and similar in spirit (though not the same attack) is in Sean Devlin's Set 7 of Cryptopals: