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Patch Critical Cryptographic Vulnerability in Microsoft Windows [pdf]

media.defense.gov

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Re: Patch Critical Cryptographic Vulnerability in Microsoft Windows [pdf]

#131

Post by baby »

Uptrenda wrote: post #22

None 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…

So you mean the signature algorithm was not fully part of the signature? Indeed that’s a recipe for disasters as the numerous TLS attacks have shown (logjam, freak, drown)

Re: Patch Critical Cryptographic Vulnerability in Microsoft Windows [pdf]

#132

Post by monocasa »

tptacek wrote: post #129
monocasa wrote: post #124

Earlier quoted context omitted.

I mean, the 0 days in the shadowbroker dumps wouldn't count as "NOBUS" backdoors either, but the NSA was sitting on those like a dragon hording gold.

Those aren't vulnerabilities NSA created, unlike Dual_EC, which is.

Neither is this crypt32 vulnerability, which is part of the analogy the parent comment is making.

Re: Patch Critical Cryptographic Vulnerability in Microsoft Windows [pdf]

#133

Post by tptacek »

monocasa wrote: post #132
tptacek wrote: post #129

Earlier quoted context omitted.

Those aren't vulnerabilities NSA created, unlike Dual_EC, which is.

Neither is this crypt32 vulnerability, which is part of the analogy the parent comment is making.

NSA disclosed this CryptoAPI vulnerability. What's the lesson to draw from that?

Re: Patch Critical Cryptographic Vulnerability in Microsoft Windows [pdf]

#134

Post by monocasa »

tptacek wrote: post #133
monocasa wrote: post #132

Earlier quoted context omitted.

Neither is this crypt32 vulnerability, which is part of the analogy the parent comment is making.

NSA disclosed this CryptoAPI vulnerability. What's the lesson to draw from that?

My point is that the structural "NOBUS" framework the parent was trying to construct has glaring, recent counter examples, and can't really be used to holistically describe their behavior over the past couple decades.

Of course I applaud responsible disclosure, and if they continue down that direction they have the possibility of rebuilding some of the trust they've broken in modern times.

Re: Patch Critical Cryptographic Vulnerability in Microsoft Windows [pdf]

#136

Post by tptacek »

monocasa wrote: post #134
tptacek wrote: post #133

Earlier quoted context omitted.

NSA disclosed this CryptoAPI vulnerability. What's the lesson to draw from that?

My point is that the structural "NOBUS" framework the parent was trying to construct has glaring, recent counter examples, and can't really be used to holistically describe their behavior over the past couple decades. Of course I applaud responsible disclosure, and if they continue down that direction they have the possibility of rebuilding some of the trust they've broken in modern times.

You've lost me. What are the glaring counterexamples to NOBUS? The NOBUS framework says that NSA introduces vulnerabilities and backdoors only when it has some assurance that only NSA will be able to exploit them. It doesn't follow that NSA would immediately disclose any vulnerabilities they discover.

Re: Patch Critical Cryptographic Vulnerability in Microsoft Windows [pdf]

#137

Post by userbinator »

1970-01-01 wrote: post #91

So Win7 isn't affected? At this point in time I have to point out a fully patched Win7, having ~8 hours of support life left, just happens to be more secure than Win10 for trusting certs.

It's called maturity... code that isn't radically changed or added to will asymptotically approach being completely bug-free as all the bugs get gradually discovered and fixed over time. This also implies that the majority of bugs are found in the newest code.

Re: Patch Critical Cryptographic Vulnerability in Microsoft Windows [pdf]

#138

Post by A4ET8a8uTh0 »

Seenso wrote: post #85
monoideism wrote: post #20

Earlier quoted context omitted.

Their mission also explicitly includes information assurance: Mission Statement The National Security Agency/Central Security Service (NSA/CSS) leads the U.S. Government in cryptology that encompasses both signals intelligence (SIGINT) and information assurance (now referred to as cybersecurity) products and services, and enables computer network operations (CNO) in order to gain a decision advantage for the Nation a…

They've got to balance both roles. IIRC, in earlier times the government didn't use as much COTS stuff, and civilian computer systems weren't so critical, so the roles were easier to separate. The NSA developed whole series of secret encryption algorithms for the exclusive use of the government/military, and civilian algorithms weren't approved to secure classified communications. https://en.wikipedia.org/wiki/NSA_cr…

I always wondered why Barr, Comey and basically every AG I paid attention to, consistently want to break encryption for the populace.

I guess it makes sense proponents of those changes would be ok of breaking it for the proles of they thought their secrets are protected.

Re: Patch Critical Cryptographic Vulnerability in Microsoft Windows [pdf]

#139

Post by tptacek »

JackRabbitSlim wrote: post #99
trulyrandom wrote: post #73

The advisory from Microsoft is quite bizarre. It focuses on code signature validation, rather than X.509 as a whole. It also doesn't say anything about how the vulnerability itself works. Vague advisories like this are dangerous, because it gives adversaries an advantage over IT departments that don't know which system they should patch first. It would be much better if everyone understood exactly what the impact is…

X509 as a whole is fine and this isn't so much arbitrary MITM of any web server. It's specific to ECC public keys(not specifically X509 certs) that validate from cryptoAPI which is a fairly limited but devastating scope. EG Code signing. Firefox uses its own NSS libraries not cryptoAPI to verify certs and is completely unaffected. I assume every major browser uses NSS or their own APIs as well. And of course RSA and…

A CERT person on Twitter was explicit about this impacting all of X.509.

Re: Patch Critical Cryptographic Vulnerability in Microsoft Windows [pdf]

#140

Post by cliqueiq »

age_bronze wrote: post #12

Nothing screams "we have microsoft keys!" harder than the fact that the only vulnerabilities reported by the NSA is a cryptographic validation bug. If I had to guess exactly what kind of vulnerabilities they do not need, this is exactly those kind. Who needs crypto validation bug when you already own microsoft's keys?!

Thinking with my tin-foil hat: Same date as windows 7 last patch right? Not sure if this was a risk decision or an intentional message.
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