February 7, 2020 - one of the biggest carriers and ISPs in Russia - MTS - AS8359, created two route leaks involving prefixes belonging to such companies as Imperva, GCore, IPTP, Akamai and many others. MTS took those prefixes from HKIX (AS4635) and sent them to Level3 (AS3356) for further distribution.
In order to (somewhat) simplify the description process and tighten the volume of the article we are going to write, it is essential to make a significant remark and state the primary constraint right away — everything we are going to tell you today on the practical side of the problematics is viable only in terms of TLS 1.3. Meaning that while your ECDSA certificate would still work in TLS 1.2 if you wish it worked, providing backwards compatibility, the description of the actual handshake process, cipher suits and client-server benchmarks covers TLS 1.3 only. Of course, this does not relate to the mathematical description of algorithms behind modern encryption systems.
This article was written by neither a mathematician nor an engineer — although those helped to find a way around scary math and reviewed this article. Many thanks to Qrator Labs employees.
(Elliptic Curve) Diffie-Hellman (Ephemeral)
The Diffie–Hellman legacy in the 21 century
Of course, this has started with neither Diffie nor Hellman. But to provide a correct timeline, we need to point out main dates and events.
There were several major personas in the development of modern cryptography. Most notably, Alan Turing and Claud Shannon both laid an incredible amount of work over the field of theory of computation and information theory as well as general cryptanalysis, and both Diffie and Hellman, are officially credited for coming up with the idea of public-key (or so-called asymmetric) cryptography (although it is known that in the UK there were made serious advances in cryptography that stayed under secrecy for a very long time), making those two gentlemen pioneers.
This report explains how the outage of a single AS can affect the connectivity of the impacted region with the rest of the world, especially when it is the dominant ISP on the market. Internet connectivity at the network level is driven by interaction between autonomous systems (AS’s). As the number of alternate routes between AS’s increases, so goes the fault-resistance and stability of the internet across the network. Although some paths inevitably become more important than others, establishing as many alternate routes as possible is the only viable way to ensure an adequately robust system.
The global connectivity of any AS, regardless of whether it is a minor provider or an international giant, depends on the quantity and quality of its paths to Tier-1 ISPs. Usually, Tier-1 implies an international company offering global IP transit service over connections to other Tier-1 providers. But there is no guarantee that such connectivity will be maintained. Only the market can motivate them to peer with other Tier-1’s to deliver the highest quality service. Is that enough? We explore this question in the IPv6 section below. For many ISPs at all levels, losing connection to just one Tier-1 peer would likely render them unreachable in some parts of the world.
Measuring Internet Reliability
Let’s examine a case where an AS experiences significant network degradation. We want to answer the following question: “How many AS’s in the region would lose connectivity with Tier-1 operators and their global availability along with it?”
TL;DR: Client-server architecture of our internal configuration management tool, QControl.
At its basement, there’s a two-layered transport protocol working with gzip-compressed messages without decompression between endpoints. Distributed routers and endpoints receive the configuration updates, and the protocol itself makes it possible to install intermediary localized relays. It is based on a differential backup (“recent-stable,” explained further) design and employs JMESpath query language and Jinja templating for configuration rendering.
Qrator Labs operates on and maintains a globally distributed mitigation network. Our network is anycast, based on announcing our subnets via BGP. Being a BGP anycast network physically located in several regions across the Earth makes it possible for us to process and filter illegitimate traffic closer to the Internet backbone — Tier-1 operators.
On the other hand, being a geographically distributed network bears its difficulties. Communication between the network points-of-presence (PoP) is essential for a security provider to have a coherent configuration for all network nodes and update it in a timely and cohesive manner. So to provide the best possible service for customers, we had to find a way to synchronize the configuration data between different continents reliably.
In the beginning, there was the Word… which quickly became communication protocol in need of an upgrade.
Today we often talk about SLA and redundancy. And the increasing role of clouds in the overall Internet infrastructure. Someone says that they will play a crucial role in traffic share in the nearest future. However, there are other huge ISPs - Tier-1, aka the biggest transit operators, which have transnational cables and indeed are part of the historical Internet backbone. They often play the role of last resort in the filtration process of bad routes. Because they have hundreds of customers. Also, almost all of these customers believe in what they got from the provider ISPs. That is the main reason why modern internet drafts rely on Tier-1s as flag carriers and hope that they’ll apply a new security mechanism among all the others.
TL;DR: starting February 2020, DNS servers that don’t support DNS both over UDP and TCP may stop working.
Bangkok, in general, is a strange place to stay. Of course, it is warm there, rather cheap and some might find the cuisine interesting, along with the fact that about half of the world’s population does not need to apply for a visa in advance to get there. However, you still need to get acquainted with the smells, and the city streets are casting cyberpunk scenes more than anything else.
In particular, a photo to the left has been taken not far from the center of Thailand’ capital city, one street away from the Shangri-La hotel, where the 30th DNS-OARC organization meeting took place on May 12 and 13. It is a non-profit organization dedicated to security, stability, and overall development of the DNS — the Domain Name System.
Slides from the DNS-OARC 30 meeting are recommended for everyone interested in how the DNS works, though perhaps the most interesting is what is absent in those slides. Namely, a 45-minute round table with a discussion around the results of DNS Flag Day 2019, which occurred on February, 1, 2019.
And, the most impressive result of a round table is the decision to repeat DNS Flag Day once again.