My father grew up on a small farm in eastern Washington. They say you can take the boy out of the farm, but you can’t take the farm out of the boy. As a kid, I was always hearing farm life sayings from my grandfather and father. To this day, I think they are some of the best pieces of advice I have ever received. Here are a few:

• Don’t wrestle with pigs. You both get filthy and the pig likes it: Avoid pointless arguments with people who thrive on conflict. It only wastes your time and energy.
• Don’t count your chickens before they hatch: Don’t assume a deal is closed until the contract is signed.
• Make hay while the sun shines: Capitalize on opportunities while they are available.
• Don’t put all your eggs in one basket: Diversify your investments and strategies to mitigate risk.
• The early bird catches the worm: Being proactive and early can lead to the best opportunities.
• Every cloud has a silver lining: Look for opportunities in every challenge or setback.
• Don’t cry over spilled milk: Learn from mistakes, but don’t dwell on them; move forward.
• When the rooster crows, it’s time to get up: Start your day early to maximize productivity.
• You can’t make an omelet without breaking a few eggs: Achieving success often requires taking some risks and making sacrifices.
• You reap what you sow: Your results are a reflection of the effort and quality you put in.
• Don’t look a gift horse in the mouth: Be grateful for opportunities and advantages you receive.
• When in doubt, let your horse do the thinking: Trust the expertise of your team when you’re unsure.
• Never approach a bull from the front, a horse from the rear, or a fool from any direction: Avoid unnecessary risks and confrontations in business.
• Don’t close the barn door after the horse has bolted: Take preventive measures rather than waiting until you need to react.
• A stitch in time saves nine: Address small issues before they become large problems.
• The squeaky wheel gets the grease: The most noticeable or pressing issues are the ones that receive the most attention and resources first.

The other day Microsoft announced something it calls Zero Trust DNS. At a high level, it is leveraging clients’ underlying name resolution capabilities to establish and enforce security controls below the application.

In design, it is quite similar to what we did in Windows 2008 and Network Access Protection (NAP), a now deprecated solution that if released today would be considered some flavor of “Zero Trust” network access control.

NAP supported several different enforcement approaches for network policy. One of the less secure methods assessed a client’s posture; if found to be non-compliant with organizational requirements, the DHCP server would assign a restricted IP address configuration. The most secure approach relied on certificate-based IPSEC and IPv6. Healthy clients were provisioned with what we called a health certificate. All participating devices would then communicate only with IPSEC-authenticated traffic and drop the rest.

If ZeroTrust DNS had been released in 2008, it would have been another enforcement mode for Network Access Protection. It operates very similarly, essentially functioning on the basis that :

1. The enterprise controls the endpoint and, through group policy, dictates DNS client behavior and network egress policy,
2. Leverage mutual TLS and DNS over HTTPS (DoH) to authenticate clients, and
3. Transform the DNS server into a policy server for network access.

I was always disappointed to see NAP get deprecated, especially the 802.1X and IPSEC-based enforcement models. Don’t get me wrong, there were many things we should have done differently, but the value of this kind of enforcement and visibility in an enterprise is immense. This is why, years later, the patterns in NAP were reborn in solutions like BeyondCorp and the myriad of “Zero Trust” solutions we see today.

So why might this ZeroTust DNS be interesting? One of the more common concerns I have heard from large enterprises is that the mass adoption of encrypted communications has made it hard for them to manage the security posture of their environment. This is because many of the controls they have historically relied on for security were designed around monitoring clear text traffic.

This is how we ended up with abominations like Enterprise Transport Security which intentionally weakens the TLS 1.3 protocol to enable attackers—erm, enterprises—to continue decrypting traffic. 

One of the theses of this Zero Trust DNS solution appears to be that by turning DNS into what we used to call a Policy Enforcement Point for the network enterprises get some of that visibility back. While they do not get cleartext traffic, they do get to reliably control and audit what domain names you resolve. When you combine that with egress network filtering, it has the potential to create a closed loop where an enterprise can have some confidence about where traffic is going and when. While I would not want my ISP to do any of this, I think it’s quite reasonable for an enterprise to do so; it’s their machine, their data, and their traffic. It also has the potential to be used as a way to make lateral movement in a network, when a compromise takes place, harder and maybe, in some cases, even make exfiltration harder.

Like all solutions that try to deliver network isolation properties, the sticking point comes back to how do you create useful policies that reduce your risk but still let work happen as usual. Having the rules based on high-level concepts like a DNS name should make this better, than with, for example, IPSEC-based isolation models, but it still won’t be trivial to manage. It looks like this will have all of those challenges still but that is true of all network segmentation approaches.

What I appreciate most about this is its potential to reduce an organization’s perceived need to deploy MiTM solutions. From a security protocol design perspective, what is happening here is a trade-off between metadata leakage and confidentiality. The MiTM solutions in use today cause numerous problems; they hinder the adoption of more secure protocol variants and objectively reduce enterprise security in at least one dimension. They also make rolling out new versions of TLS and more secure cryptography that much harder. Therefore, in my opinion, this is likely a good trade-off for some organizations.

To be clear, I do not believe that host-based logging of endpoint communications will lead all enterprises to abandon these MiTM practices. For example, some MiTM use cases focus on the intractable problems of Data Leak Protection, network traffic optimization, or single sign-on and privilege access management through protocol-level manipulation. These solutions clearly require cleartext access, and name-based access control and logging won’t be enough to persuade enterprises that rely on these technologies to move away from MiTM. However, there are some use cases where it might.

So, is this a good change or a bad change? I would say on average it’s probably good, and with some more investment from Microsoft, it could be a reasonable pattern to adopt for more granular network segmentation while giving enterprises more visibility in this increasingly encrypted world without needing to break TLS and other encryption schemes.

Have you found a use case where you think DANE and DNSSEC might be helpful? For example, the discovery of some configuration associated with a domain? Since a practically useful DNSSEC deployment, which requires individual domains (ex: example.com) to adopt DNSSEC and for relevant clients to use a fully validating DNSSEC resolver, which has not happened yet at any reasonable scale, maybe consider using certificates to sign the values you place in DNS instead.

SXG certificates are, in essence, signing certificates tied to a domain, while you could use a regular TLS certificate, for today’s post let’s assume that SXG certificates were the path you chose.

You can enroll for SXG certificates for free through Google Trust Services. This would allow you to benefit from signed data in DNS that is verifiable and deployable today not only once DNSSEC gets broad deployment.

Assuming a short certificate chain, since DNS does have size restrictions, this could be done as simply as:

Get an SXG certificate that you can use for signing….

sudo certbot certonly \
  --server https://dv-sxg.acme-v02.api.pki.goog/directory \
  -d yourdomain.com \
  --manual \
  --eab-kid YOUR_EAB_KID \
  --eab-hmac-key YOUR_EAB_HMAC_KEY

Sign your data….

openssl smime -sign -in data.txt -out signeddata.pkcs7 -signer mycert.pem -inkey mykey.pem -certfile cacert.pem -outform PEM -nodetach

Then put the data into a DNS TXT record….

After which you could verify that using the Mozilla trust list using OpenSSL…

openssl smime -verify -in signeddata.pkcs7 -CAfile cacert.pem -inform PEM

In practice, due to DNS size constraints, you would likely use a simpler signature format, such as encoding just the signing certificate and the signature in Base64 as a type-length-value representation; with a 256-bit ECC certificate and its signature, this record would total around 1152 bytes, which would comfortably fit inside a DNS TXT record, thanks to EDNS which has a capacity of up to 4096 bytes.

While this does not provide the authoritative non-existence property that DNSSEC has, which exists to address downgrade attacks, which means relying parties could not detect if the record was removed, nor does it provide security to DNS overall, but if we are just talking about configuration data, it might be a viable approach to consider.

On the other hand, this form of signing a TXT record using a certificate is never going to take down your domain and DNSSEC adoption cannot say that!

Firmware forms the foundation of all our security investments. Unfortunately, firmware source code is rarely available to the public and as a result is one of the least understood (and least secure) classes of software we depend on today.

Despite this, the hardware industry is known for its lack of transparency and inadequate planning for the entire lifecycle of their products. This lack of planning and transparency makes it hard to defend against and respond to both known and unknown vulnerabilities, especially when the industry often knows about issues for ages, but customers do not.

In today’s world, automation allows builders, defenders and attackers to automatically identify zero-day vulnerabilities with just a binary it has become increasingly important that embargo times for vulnerabilities are as short as possible, allowing for quick defense and, when possible, remediation.

Despite this, organizations like the UEFI Forum are proposing extended disclosure periods, suggesting a 300-day wait from initial reporting to the vendor before notifying customers. During this year-long waiting period, customers are exposed to risks without defense options. The longer the period, the more likely it is that automation enables the attacker to identify the issue in parallel, giving them a safe period to exploit the zero-day without detection.

Simply put, this duration seems way too long, considering the ease of proactively catching issues now — especially given the industry’s overall underinvestment in product security. It would be a different case if these organizations had a history of handling issues effectively, but the reality is far from this. Their apparent neglect, demonstrated by unreliable update mechanisms, continuously shipping models with the same issues that have been resolved in other models, and the frequency of industry-wide issues highlight this reality. More often than any other industry, we see hardware manufacturers often reintroducing previously resolved security issues due to poor security practices and poor management of their complex supply chains. This reality makes this position highly irresponsible. We must do better. Concealing vulnerabilities like this is no longer viable — if it ever was.

It is possible we will see changes as a result of shifts in software liability and regulatory changes, like those in White House Executive Order 1428. This order demands that organizations responsible for “critical software” comply with long-standing best practices. Although “critical software” lacks a clear definition, firmware’s role in underpinning all security investments suggests it likely falls into this category. This executive order starts with basics like publishing known dependencies, which is useful but insufficient, especially in this segment given the prevalence of shared reference code and static dependencies that are not expressed as a library dependencies. This language includes adoption of formal vulnerability management practices, bug bounties, and more. This and the EU Cyber Resilience Act are all efforts to get these and other vendors to align with long-time security best practices, like those captured by efforts like the NIST’s vulnerability management recommendations.

This landscape will likely shift once we see enforcement cases emerge, but customers must insist on higher standards from hardware manufacturers and their suppliers, or nothing will change in the near term.

I was listening to Security Cryptography Whatever today, and they were discussing a topic that has been bothering me for a while.

A common theme in post-quantum cryptography is its pairing with classical cryptography. This “belts and suspenders” approach seems sensible as we transition to relatively new ways to authenticate and protect data. We have already seen some of these new post-quantum methods fail, which underscores the importance of agility in these systems.

However, merging two approaches like this introduces complexity, which is important since as a general rule, complexity is the root of all security issues. Another concern is the labeling of various strategies for doing this as “Hybrid.” This wording makes it challenging to understand what the different approaches are doing and why.

With this background in mind, let’s explore three different “Hybrid” approaches to PQC and classical cryptography. By giving each a unique name and using simple examples, to see if we we can show how they differ: Nested Hybrid Signatures, Side-by-Side Hybrid Protocols, and the proposed Merged Hybrid Signatures.

Nested Hybrid Signatures: A box within a box

In this approach, imagine verifying the authenticity of a letter. The nested hybrid signature method is like putting this letter within a secure box, protected by a classical signature scheme like ECDSA. But we don’t stop there. This box is then placed within another, even stronger box, strengthened with a post-quantum signature scheme like Dilithium. This nested structure creates a situation where even if one layer is broken, the inner core remains trustable..

Side-by-Side Hybrid Protocols: Simultaneous and Nested

In this method, imagine two separate safes, each protecting a part of your secret message. One safe has a classical lock, while the other has a modern, quantum-resistant lock. To see the entire message, one must unlock both safes, as the full message remains trustable unless both safes are broken into. 

Merged Hybrid Signatures: Holding onto the past

This method tries to mix the elements of classical and post-quantum signature schemes into a single, unified signature format. The goal of this approach is to enable minimal changes to existing systems by maintaining a single field that combines a classical signature with a post-quantum signature. This has several issues and seems misguided to me. Firstly, this mixing of PQC and classical cryptography is a temporary problem; eventually, we should have enough confidence that post-quantum cryptography alone is enough at which point this complexity wouldn’t be needed. It also messes with the current assumptions associated with existing signatures, and while it’s not clear what the issues may be, keeping each of the signatures isolated seems less risky. To stick with the lock analogy, it’s somewhat like designing a safe with two different locks on the same door, which must be unlocked at the same time with the same key.

Conclusion

While it’s tough to find the right words to describe new developments as they happen we can do better to avoid using the same terms for different approaches. This will make it easier for everyone to understand what’s being discussed without having to study each protocol in detail. 

Caddy is a powerful and easy-to-use web server that can be configured to use a variety of certificate authorities (CA) to issue SSL/TLS certificates. One popular CA is Google Trust Services, which offers an ACME endpoint that is already compatible with Caddy because it implements the industry-standard ACME protocol (RFC 8555). 

This means that Caddy can automatically handle the process of certificate issuance and renewal with Google Trust Services, once the External Account Binding (EAB) credentials required have been configured. 

How do I use it? 

Using global options

To use the Google Trust Services ACME endpoint you will need an API key so you can use a feature in ACME called External Account Binding. This enables us to associate your certificate requests to your Google Cloud account and allows us to impose rate limits on a per-customer basis. You may easily get an API key using the following commands:

$ gcloud config set project <project ID> $ gcloud projects add-iam-policy-binding project-foo \  –member=user:[email protected] \  –role=roles/publicca.externalAccountKeyCreator # Request a key: $ gcloud alpha publicca external-account-keys create

You will need to add this API key and specify the Google Trust Services ACME directory endpoint along with your email address in your Caddyfile:

{     acme_ca https://dv.acme-v02.api.pki.goog/directory email  [email protected] acme_eab {         key_id  <key_id>         mac_key <mac_key>     }}

It is important to remember that when you use this configuration Google Trust Services explicitly is used as the only CA.

If you want to use multiple CAs for redundancy Caddy which is recommended the configuration would look something like this:

{      cert_issuer acme https://dv.acme-v02.api.pki.goog/directory  {           eab <key_id>  <key>      }      cert_issuer acme }

In this example Google Trust Services will be tried and if there is a problem it will fall back to Let’s Encrypt.

It is also worth noting that the Google Trust Services EAB key is one time use only. This means that once Caddy has created your ACME account these can be safely removed.

Using the tls directive

If you want to use Google Trust Services for only some of your sites, you can use the tls directive in your Caddyfile like you’re used to:

tls [email protected] {     ca https://dv.acme-v02.api.pki.goog/directory    eab <key_id> <mac_key> }

The email address in this example identifies the ACME account to be used when doing enrollment.

In conclusion, using Caddy with Google Trust Services is a simple and simple and secure way to issue and manage SSL/TLS certificates for your websites. With the easy-to-use Caddyfile configuration, you can quickly and easily configure your server to use Google Trust Services for all of your sites or just a select few. With Google Trust Services, you can trust that your websites will be secure and your visitors’ data will be protected.

As Google Trust Services has been available for a few weeks I thought it would be interesting to look at where it stands relative to other CAs based on its issuance volume.

#	CA Owner	Certificates			Pre-Certificates
		All	Unexpired	All	Unexpired
1	Internet Security Research Group	2,972,072,131	270,986,317	2,689,923,862	233,570,311
2	DigiCert	115,808,406	7,603,151	443,129,508	138,144,685
3	Sectigo	580,982,481	45,262,868	517,794,477	46,204,659
4	Google Trust Services LLC	13,909,548	467,650	120,070,013	21,232,287
5	Microsoft Corporation	17,567	170	32,448,453	16,959,805

For more on this methodology of counting see this post.

When I was a boy my father had me read Plato’s Republic – he wanted to give an oral report on what the key points of the book were and what my personal takeaways were after reading the book.

The first question was easy to answer from the dust jacket or maybe a Cliff Notes (For those of you who have not read the book it is an exploration of the ideas of justice and the ideal government).

With that said, I knew from experience that those personal takeaways are buried in the nuance and no shortcut would satisfy him so off to read I went. What were those takeaways? According to him what I said was: 

1. The nature of people has not changed much,
2. The problems we have in government have not changed much.

Why do I bring this up in the context of security? Unfortunately, it is because I do not think things have changed much in security either! I’ll give two examples that stand out to me:

Every program and every privileged user of the system should operate using the least amount of privilege necessary to complete the job.

— Jerome Saltzer, 1974, Communications of the ACM

The moral is obvious. You can’t trust code that you did not totally create yourself. (Especially code from companies that employ people like me.) No amount of source-level verification or scrutiny will protect you from using untrusted code.

Ken Thompson, 1984, Reflections on Trusting Trust

The first quote is the seminal quote referring to the term “least privilege” – a concept we still struggle to see deployed nearly 50 years later. The term is old enough now the marketers have latched onto it so when you speak to many enterprises they talk about it in the scope of group management and not the more fundamental design paradigm it actually represents.

To put this concept in the context of the network in the 90s we talked about how Firewalls, however necessary, were a bit of an antipattern since they represented “the hard candy shell” containing the “soft gooey sweet stuff” the attacker wants to get at and that as a result, it was better to design security into each endpoint. 

A decade later we were talking about using network-level enforcement via “Network Admission Control” at the switch, later yet via DirectAccess and Network Access Protection we were pushing those same decisions down as close to the end device as we could, and in some cases making each of those endpoints capable of enforcing these access requests.

Today we call this pattern ZeroTrust networking, a leading example of this pattern is called BeyondCorp, but again marketers have latched onto ZeroTrust and as a result, it seems almost every enterprise product I hear about these days claims to offer some sort of ZeroTrust story but few objectively meet the criteria I would define for such a lofty term.

Similarly, if we look at the second quote all we have to do is take a look at the recent SolarWinds debacle and realize that almost nothing has changed since Ken Thompson wrote that paper. We also have dozens of examples of keys being compromised being used to attack the software supply chain, or package repositories and open source dependencies being used as attack vectors. Despite us knowing how significant these issues can be for nearly 40 years we have made very little progress in mitigating these issues.

As they say, there is nothing new under the sun, and this appears to be especially true with security. If so why is this the case? How is it we have made so little progress on these fundamental problems as an industry?

Unfortunately, I think it boils down to that customers don’t care until it is too late and this makes it hard for the industry to justify the kinds of fundamental investments necessary to protect the next generation from these decades old.

How do we improve the state of affairs here? Thats really the question, one I don’t have a good answer to.