Reducing RPKI Single Point of Takedown Risk

21 September 2020 | Comments Off on Reducing RPKI Single Point of Takedown Risk

The RPKI, for those who do not know, ties the origin AS to a prefix using a certificate (the Route Origin Authorization, or ROA) signed by a third party. The third party, in this case, is validating that the AS in the ROA is authorized to advertise the destination prefix in the ROA—if ROA’s were self-signed, the security would be no better than simply advertising the prefix in BGP. Who should be able to sign these ROAs? The assigning authority makes the most sense—the Regional Internet Registries (RIRs), since they (should) know which company owns which set of AS numbers and prefixes.

The general idea makes sense—you should not accept routes from “just anyone,” as they might be advertising the route for any number of reasons. An operator could advertise routes to source spam or phishing emails, or some government agency might advertise a route to redirect traffic, or block access to some web site. But … if you haven’t found the tradeoffs, you haven’t looked hard enough. Security, in particular, is replete with tradeoffs.

Zero Trust and the Cookie Metaphor

13 July 2020 | Comments Off on Zero Trust and the Cookie Metaphor

In old presentations on network security (watch this space; I’m working on a new security course for Ignition in the next six months or so), I would use a pair of chocolate chip cookies as an illustration for network security. In the old days, I’d opine, network security was like a cookie that was baked to be crunchy on the outside and gooey on the inside. Now-a-days, however, I’d say network security needs to be more like a store-bought cookie—crunchy all the way through. I always used this illustration to make a point about defense-in-depth. You cannot assume the thin crunchy security layer at the edge of your network—generally in the form of stateful packet filters and the like (okay, firewalls, but let’s leave the appliance world behind for a moment)—is what you really need.

The Hedge Pdocast Episode 43: Ivan Pepelnjak and Trusting Routing Protocols

8 July 2020 | Comments Off on The Hedge Pdocast Episode 43: Ivan Pepelnjak and Trusting Routing Protocols

Can you really trust what a routing protocol tells you about how to reach a given destination? Ivan Pepelnjak joins Nick Russo and Russ White to provide a longer version of the tempting one-word answer: no! Join us as we discuss a wide range of issues including third-party next-hops, BGP communities, and the RPKI.

The Hedge Podcast Episode 42: Andrei Robachevsky and MANRS

1 July 2020 | Comments Off on The Hedge Podcast Episode 42: Andrei Robachevsky and MANRS

The security of the global routing table is foundational to the security of the overall Internet as an ecosystem—if routing cannot be trusted, then everything that relies on routing is suspect, as well. Mutually Agreed Norms for Routing Security (MANRS) is a project of the Internet Society designed to draw network operators of all kinds into thinking about, and doing something about, the security of the global routing table by using common-sense filtering and observation. Andrei Robachevsky joins Russ White and Tom Ammon to talk about MANRS.

More information about MANRS can be found on the project web site, including how to join and how to support global routing security.

Research: Off-Path TCP Attacks

22 June 2020 | Comments Off on Research: Off-Path TCP Attacks

I’s fnny, bt yu cn prbbly rd ths evn thgh evry wrd s mssng t lst ne lttr. This is because every effective language—or rather every communication system—carried enough information to reconstruct the original meaning even when bits are dropped. Over-the-wire protocols, like TCP, are no different—the protocol must carry enough information about the conversation (flow data) and the data being carried (metadata) to understand when something is wrong and error out or ask for a retransmission. These things, however, are a form of data exhaust; much like you can infer the tone, direction, and sometimes even the content of conversation just by watching the expressions, actions, and occasional word spoken by one of the participants, you can sometimes infer a lot about a conversation between two applications by looking at the amount and timing of data crossing the wire.

The Hedge Podcast 037: Stephane Bortzmeyer and DNS Privacy

27 May 2020 | Comments Off on The Hedge Podcast 037: Stephane Bortzmeyer and DNS Privacy

In this episode of the Hedge, Stephane Bortzmeyer joins Alvaro Retana and Russ White to discuss draft-ietf-dprive-rfc7626-bis, which “describes the privacy issues associated with the use of the DNS by Internet users.” Not many network engineers think about the privacy implications of DNS, a important part of the infrastructure we all rely on to make the Internet work.

Reflections on Intent

20 April 2020 |

No, not that kind. 🙂

BGP security is a vexed topic—people have been working in this area for over twenty years with some effect, but we continuously find new problems to address. Today I am looking at a paper called BGP Communities: Can of Worms, which analyses some of the security problems caused by current BGP community usage in the ‘net. The point I want to think about here, though, is not the problem discussed in the paper, but rather some of the larger problems facing security in routing.

An Interesting take on Mapping an Attack Surface

23 March 2020 | Comments Off on An Interesting take on Mapping an Attack Surface

Security often lives in one of two states. It’s either something “I” take care of, because my organization is so small there isn’t anyone else taking care of it. Or it’s something those folks sitting over there in the corner take care of because the organization is, in fact, large enough to have a separate security team. In both cases, however, security is something that is done to networks, or something thought about kind-of off on its own in relation to networks.

I’ve been trying to think of ways to challenge this way of thinking for many years—a long time ago, in a universe far away, I created and gave a presentation on network security at Cisco Live (raise your hand if you’re old enough to have seen this presentation!).

The Hedge Podcast Episode 19: Optional Security is not Optional

22 January 2020 | Comments Off on The Hedge Podcast Episode 19: Optional Security is not Optional

Brian Trammell joins Alvaro Retana and Russ White to discuss his IETF draft Optional Security Is Not An Option, and why optional security is very difficult to deploy in practice. Brian blogs at http://trammell.ch and also writes at APNIC.

Research: Securing Linux with a Faster and Scalable IPtables

25 November 2019 |

If you haven’t found the trade-offs, you haven’t looked hard enough.

A perfect illustration is the research paper under review, Securing Linux with a Faster and Scalable Iptables. Before diving into the paper, however, some background might be good. Consider the situation where you want to filter traffic being transmitted to and by a virtual workload of some kind, as shown below.

To move a packet from the user space into the kernel, the packet itself must be copied into some form of memory that processes on “both sides of the divide” can read, then the entire state of the process (memory, stack, program execution point, etc.) must be pushed into a local memory space (stack), and control transferred to the kernel. This all takes time and power, of course.