Category: Security

Doug Madory wrote an interesting article (published on APNIC blog) arguing that we shouldn’t worry about ephemeral BGP leaks that can be observed only during the BGP path hunting process that follows a route withdrawal.

I have to disagree with that. It’s never a good idea to ignore a dead canary in the coal mine.

While the ephemeral leaks do not impact the end result (after all, the route is gone), they are an important indicator of the lack of BGP route policy enforcement in the autonomous systems that propagate them. If an autonomous system is propagating a bogus route when no better routes are available, it’s equally likely to propagate a bogus route when an intruder manages to inject it.

In October 2023, I was talking about Internet routing security at the DEEP conference in Zadar, Croatia. After explaining the (obvious) challenges and the initiatives aimed at making Internet routing more secure (MANRS), I made my usual recommendation: vote with your wallet. However, if you’re a company in Croatia (or Slovenia, or a number of other countries), you’re stuck.

While ISPs in Croatia might be doing a great job, none of them is a MANRS participant¹, so we don’t know how good they are. The situation is not much better in Slovenia; the only ISPs claiming to serve Slovenia are Anexia (a cloud provider) and Go6 Institute, the small network operated by my good friend (and True Believer in IPv6 and MANRS) Jan Žorž. Moving further north, there are decent choices in Austria, and tons of options in Germany or Switzerland. I must be living in a truly thrifty part of Europe.

Today is a perfect day to point out the fantastic Why Quantum Cryptanalysis is Bollocks presentation (HT: A blog post by George Michaelson)

It’s a must-read, even if you’re absolutely uninterested in the topic. Just replace “Quantum mumbo-jumbo” with AI or SDN ;) Have fun!

My Internet Routing Security talk from last year’s DEEP conference (a shorter version of the Internet Routing Security webinar) is now available on YouTube.

Hope you’ll find it useful ;)

Sharada Yeluri published an interesting overview of the evolution of network security, from packet filtering firewalls to GenAI and Quantum Computing (yeah, she works for a networking vendor ;). Definitely worth reading if you’re looking for an intro-level overview.

A long-time friend sent me this question:

I would like your advice or a reference to a security framework I must consider when building a green field backbone in SR/MPLS.

Before going into the details, keep in mind that the core SR/MPLS functionality is not much different than the traditional MPLS:

Another cybersecurity rant worth reading: cybersecurity is broken due to lack of consequences.

Bonus point: pointer to RFC 602 written in December 1973.

After checking what routers do when they receive a TCP SYN packet from an unknown source, I couldn’t resist checking how they cope with TCP SYN packets with too-low TTL when using TTL security, formally known as The Generalized TTL Security Mechanism (GTSM) defined in RFC 5082.

TL&DR: Not bad: most devices I managed to test did a decent job.

The previous BGP-related videos described how fat fingers and malicious actors cause Internet outages.

Today, we’ll focus on the impact of bugs in BGP implementations, from malformed AS paths to mishandled transitive attributes. The examples in the video are a few years old, but you can see similar things in the wild in 2023.

A while ago, the Networking Notes blog published a link to my “Will Network Devices Reject BGP Sessions from Unknown Sources?” blog post with a hint: use Shodan to find how many BGP routers accept a TCP session from anyone on the Internet.

The results are appalling: you can open a TCP session on port 179 with over 3 million IP addresses.