GoKawiilParallel Reconstruction of Lawful TLS Wiretapping
Transport Layer Security (TLS) is the protocol involved in getting the lock icon to appear in your browser next to the URL. Under the hood it uses a bunch of really cool numbers for encryption. Some numbers are considered private and need securing; some are considered public and are fine for sharing. You can mix your numbers with other people’s numbers in such a way that you can verify a chain of trust. Ultimately, at the top of this chain there has to be an entity or entities that are implied to be trustworthy, so that the links further down the chain of numbers can inherit that trust. This is the role of a root Certificate Authority (CA) at the top (root) of the chain.
There is, of course, a lot of nuance and detail missing from this high-level explanation of TLS and CA trust, but rest assured that understanding how things are supposed to work bears little influence on the ability to simply do things anyway.
As a baseline, TLS wiretapping (presumably lawful) with root-CA-signed certificates is a thing that both happens and verifiably has happened.
This being a fact rather than a conspiracy theory tends to upset people. Meanwhile, if you understand the mechanics at play, it’s objectively very funny that someone likely forgot to renew the TLS certificate for a lawful intercept, resulting in a huge warning page for users and ultimately prompting the detailed investigation seen in the link above. It’s a rather amusing way to burn an operation.
In this blog, we’ll exercise the benefit that hindsight is 20/20 and further suspend our expectations of how TLS is supposed to work. We’ll take a look at the analysis, the recommendations, and the factors in the larger system that was the year 2023, to attempt to answer how it actually could have worked, with a demonstration.
Analysis
The analysis blog on valdikss.org is extremely detailed, which is particularly useful since these things are almost exclusively only ever seen when an operational mistake occurs. I can’t “read” in the traditional left-to-right sense; it’s more like a smattering of a word cloud, and I’ve got 30+ years of experience correctly guessing the order. Allow me to demonstrate the value of that visually as we read through an analysis.
Big things are easy to guess the relevance of, but if the mystery were obvious it wouldn’t be a mystery. The devil’s in the details, and acme.sh (with the arrow pointing to it) is very small.
When you process information this way, you lose the ordering of relevance. I typically skim a document deliberately, looking for numbers indicative of time so I can put it together in my head.
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