Patch Critical Cryptographic Vulnerability in Microsoft Windows [pdf]
None of these links describe how the exploit works.<p>I found this: <a href="https://media.defense.gov/2020/Jan/14/2002234275/-1/-1/0/CSA-WINDOWS-10-CRYPT-LIB-20190114.PDF" rel="nofollow">https://media.defense.gov/2020/Jan/14/2002234275/-1/-1/0/CSA...</a><p>So based on my limited understanding:<p>1. The certificates have a place for defining curve parameters.<p>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.<p>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.<p>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)?<p>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?