IETF discusses improving NTP security

There is a new effort by standard bodies to secure the utterly broken NTP time protocol.

The proposal docs below document a ton of attacks possible when time is manipulated. Worth adding to the Time Attacks page. “Don’t use Tor/sdwdate on the desktop they said” :wink:

@Patrick I really want to see your comments get through to them sice you’ve spent a lot of time researching and implementing a secure alternative.



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2 posts were merged into an existing topic: Suggest Trustworthy Tor Hidden Services as Time Sources for sdwdate

Some of the smaller sites probably don’t qualify as “having great amount of traffic” then. For example, anonguide.cyberguerrilla.org or ev0ke.net.

How is local hardware a reliable source for time vs a large data center? where will distortions more likely to be noticed? where do they get their time from? probably ntp? do the smaller securedrop-centered site care much about accurate time?

Is the “securedrop pool” (or any pool) regularly quite off in relation to the larger servers time? I would assume it’s the case. Any stats collected regarding that? any stats collected regarding which of the 3 groups ends up supplying the median time value? in a perfect world it should be 33% chance for each group. if we check and find that it’s 50% or 70% chance for one of the groups to supply the chosen onion (due to frequently inaccurate time in the others, or a consistent bias to having late or early in some types of servers) that’s an issue. Any attempts done to check those points?

Not that I have a better way, but the whole concept looks pretty subjective. Which pools are “likely to keep their users privacy” becomes highly speculative when we need a large number of servers.

According to riseup’s own admission, their servers are occasionally taken and examined by authorities. They had the canary saga a couple of years ago. Still considered a “pal”?

Is it better to have 10 well-trusted and high-volume servers instead of 20+ maybe’s?

onion vs clearnet: in the case of clearnet (Tails pools use clearnet AFAIK) at least we know for sure on which servers they are.

Anyone maintains those list? are there onions that are not accessible over a long period of time that need to be removed? any mechanism (not in users side) to regularly cycle through them and check availability or response times? is there any fixed procedure to periodically evaluate the list?

A post was merged into an existing topic: Suggest Trustworthy Tor Hidden Services as Time Sources for sdwdate

Some questions were answered here:

Quite possible.

Speculate ntp indeed.

It’s a problem indeed. sdwdate-server project is non-existing. It’s like starting another project.

Might not.



Indeed huge risk of law of triviality / bikeshed.

For some aspects possibly yes. Downsides:

  • then these 10 servers become more worthwhile targets.
  • too few servers might result in too much traffic for these servers and then them blocking sdwdate (by removing time from http header).

The issues are rather obvious. You noticed quite a few of them. sdwdate requires development contributions.


Less likely that bad actors have access to the hardware for intentional manipulation of answers for time queries.

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