They call me the content machine. I write about information security topics, with an emphasis on cryptography and distributed denial-of-service (DDoS) attacks. I've written for DarkReading, SC Magazine, and Network World. But most people know me from my monthly column at SecurityWeek.
Click the selectors in the Content pane to filter the content.
After receiving some media inquiries around the Philippines national ID system, I put together an essay, with the help of my indispensible personal assistant in the islands, on data privacy and the Philippine National ID system (PhilSys). Back End Systems quoted me from the essay in this article, but I'm hoping that the original gets reprinted somewhere else, because it was pretty good!
Here's a video interview done by none other than F5's Calvin Rowland himself. He and I are both 17-year veterans of F5 Networks, and we're both good (or at least energetic) on video. He's interviewing me for our Agility Live series, and I'm discussing some of our security research at F5 labs.
Here's an interview I did for Info Risk Today about blockchain and the Internet of Things.
Here's a video interview of me talking about multi-cloud security. I don't honestly remember what I said it was so long ago but I'm sure it was dripping with profundity.
This is basically me channelling a series of emails with Marc LeBeau. He gave me permission to submit it as an article and I really like the way it came out. BTW can you guess the racy password that my editors didn't want me to write about?
Here's an audio interview I did at the Australian CyberSecurity Conference at Canberra in April of 2018. About 10 minutes. A little background noise, because we just did it in a quietish corner of the conference.
ISMG's Suparna Goswami interviewed me about my thoughts on IoT Security. 12 minutes of David Holmes braindumping IoT security at you.
IT Pro wrote an article based on our media briefing in HK. I don't actually know what it says, but I think it's something like "44% of Telnet scans (or attacks) coming from China". Google Translate doesn't work for cantonese?
Someone asked me what I thought about the recently passed Singapore Cybersecurity Statute. So I did some research and turned it into an article for SecurityWeek.
Malay Business Insight's coverage of F5 Labs' Hunt for IoT Volume 4 report.
My recommendations on how to spot cryptocurrency mining malware on your network and what to do when you spot it.
Here's the podcast of an interview I gave for Data Breach Today and Info Risk Today to Suparna Goswami of ISMG. This is basically the podcast version of the stump speech I give about securing IoT.
Slightly explicit content here. Was talking with my colleague Justin, and he was saying how the latest list of command-and-control hostnames for the Mirai botnet contained some hilarious examples like "cnc.smokemethallday.tk". We thought it would be a good for a laugh to do some analysis on the names where the servers are hosted from.
Never thought I'd see this day! THE Steve Gibson of the Security Now! podcast really liked the REAPER piece that Justin Shattuck and I wrote. He liked it so much he basically read it over the air on podcast episode 635 (toward the end). Still can't believe it, how cool is that?
CSO Online picked up the Maria Korolov's interview did with me and republished it. That's pretty awesome!
I promised some really nice reporters in Singapore that I would get them my top three safety tips for IoT. So I put together this little blog and posted it on LinkedIn. I think we might expand it for an cyber site somewhere.
Here's the keynote I did for F5's security event in Singapore in June. I teach the audience how to threat model the internet of things (iot),
Maria Korolov interviewed and quoted me extensively for a Data Center Knowledge piece on WannaCry. I had no time to prepare for this interview, and was surprised when it got published. Sometimes I prepare a LOT and nothing comes of it. You never know, I guess. Just keep doing them.
In Singapore I did a media event espousing F5's original IoT research. Here's a write-up from Networks Asia (or Security Asia) not such which.
Had a fantastic, wide-ranging interview with Malaya Business Insight reporter Raymond Gregory.
This article summarizes the security findings contained with the F5 state of application delivery report. Are attacks getting more sophisticated? Are employees more or less of a secure challenge than last year? Some of the findings surprise me.
My series on Threat Modeling the Internet of Things continues. This piece explains the process of threat modeling and provides some tips on how to work with your team to get it right.
The Intel Active Management Technology (AMT) vulnerability (now referred to by many as “Silent Bob”) is one of those truly brutal, ugly ones that make you queasy to even think about. Like Heartbleed or Venom. Here's how to scan for it on your network. And what ports to block.
Here's a 7 minute interview that CSO's Anthony Caruana did with me at the CSO Perspectives roadshow; this one was in Sydney. He asks about the new National Mandatory Breach Notification law, the Internet of Things, and where did I get that awesome shirt? Belgium.
Here's a funny little piece I wrote about my drinking. No, I mean about making predictions. I mean resolutions. The backstory is that the PR firm always wants a prediction piece, but I think prediction pieces are terrible! Because if I could predict the future I would be way richer than I already am. So instead we disguise these pieces as "resolutions" LOL.
A fine article about evaluating the risks and creating sound strategy around moving to Office365. In the article I briefly mention 5 threats you should add to your threat modeling for cloud collaboration. Threat modeling for cloud could, and should, be its own article or even series of articles. Remind me to write that! :)
User federation is absolutely the best way to provide user authentication in the cloud. But the recent Yahoo! breach may have dimmed enthusiasm for federated Yahoo! logins, which is a shame because reasons. The reasons in this piece :)
Q: Explain who you are and what you do
Thank you. Before we start, I need you to promise me something. You can only ask me one question about Donald Trump, okay? No more than that.
Q: How long have you been at F5?
I’ve been at F5 for 16 years, which is an eternity in the tech world. I was the last person hired during the so-called dot-com bust, during which time a hiring freeze was put in place. On my first day, there were already rumors of layoffs, and I thought “oh no, I am the new guy, of course they will eliminate my position!” So I worked day and night to show my value but I six months later I was still “the new guy”. One day the police sent us a picture of a dead body in an F5 T-shirt and I thought “oh no, the reduction in workforce is really starting!” But it turned out to be a homeless man who had gotten the shirt from the local food bank. Anyway…
Q: Many people know F5 from their ADC solutions, why the increased focus on security these days?
Yes, many people know F5 as the world’s most-expensive, I mean the world’s best load balancer, but what they don’t realize is that we’ve spent the last 10 years moving into Security. There are two reasons for this.
First, the reason it is called an ADC and not just a LB is because it naturally consolidates adjacent functions, such as caching or acceleration but now security functions like firewalls as these technologies become commodities.
Second, F5 is the number one commercial SSL termination device. If someone is paying to decrypt SSL, they are most likely deploying F5 devices. As more and more of the world’s traffic goes encrypted, it makes the F5 the first device in the network that can do layer 7 security controls. And that means attaching WAF functionality, or doing cookie inspection, or passing through to devices like FireEye. Q: You travel the globe as part of your job – do you see that security has a different place on the agenda here in Europe than North America for instance?
This is my 13th country, and fourth continent visited in 2016. So I do get to see a bit of how businesses are dealing with security around the world. What I can say about Europe is that continually impressed at the technical depth of the security professionals here. In my opinion, Europe has the best defensive security expertise in the world. There are so many excellent security conferences here, such as the CCC in Germany, RSA Europe and Hack-in-the-box in Amsterdam. The level of security awareness among everyday operations people is excellent as well.
Belgium functions as a hub in Europe. Many organisations have European headquarters here and you have institutions like the European Parliament and NATO. Naturally the security demands of these organisations are extremely high. Perhaps this is also one of the reasons the security expertise in EMEA is so high and organisations like Securelink are instrumental in maintaining the security at the highest level.
I remember one conversation I had with a customer in eastern Europe, and then first thing he said was <accent here> “David, ve will not put our data in Amerikan cloudt.”
Q: What about Australia or New Zealand?
Australia is the opposite. They are SUPER friendly with public cloud. In 2012 one of the CIOs of their four banks gave a keynote where he announced that his bank was aggressively adopting a “cloud first” strategy. Now there are telcos there that are trying to re-sell “multi-cloud” solutions but it’s tricky. Multi-cloud might seem like the ultimate availability solution, but I think we’re years away from consistent, reliable APIs.
Q: What about Africa?
Africa has its own challenges. In Nigeria, distributed denial of service is getting to be a thing, so of course we try to sell them our DDoS service. This service is classified as “Insurance” but nobody in Nigeria believes in insurance and even if they did, they want the premium to be approximately 0 euros.
Also, a big security thing in Africa right now are little plastic physical locks that you put on your Ethernet ports. They are locked with a key. [ aside: they keep the key taped under the desk ]. That’s Africa.
Q. We see many organisations looking at their cloud strategy, public vs private etc. How do you think organisations should handle their security when moving to a hybrid or public cloud scenario?
Let me give you three short cuts for cloud security, whether that’s public, private or hybrid.
For users, deploy federated logins using SAML assertions. You get SSO and don’t have keep your passwords in the cloud. And if you do it right, you can even prevent your passwords from ever transiting to the cloud and back. There’s a trick to it and we’re helping a lot of people right now who are transition to Office 365 and don’t want the CXO passwords going to Microsoft.
Second, for applications, when possible, embed your application security policy into your applications! So if you move them to the cloud, the policy goes with them. Or if they burst here and there or jump clouds, the policy goes with them too.
Lastly, if you’re considering moving to the cloud, leave your really old legacy stuff behind. If an app isn’t based on a recent Windows or Linux suite, it’s often not worth moving it to the cloud. The analyst firm Securois has an interesting term for people who try to move their really old apps to the cloud: cloud tourists. They visit the cloud, look around, start to spend some money, realize that it’s a sunk cost and not going to get them any value, and they go back home.
Q. Let’s talk about so-called Hacktivism. You track Anonymous, right? What is Anonymous doing?
I love anonymous. They used to have a brilliant leader named Sabu (expand). But lately they’ve been somewhat floundering – not a real central figure since then ( e.g. Anonymous 127.0.0.1 story).
However, they have launched their own political party in the United States called The Humanity Party, or ThuMP for short. It has three main tenants, the first of which is to establish a single, united one-world Government (the United Kingdom has already voted out of it). The other two are social equality and um, free WiFi for everyone. Can’t say I disagree with that last one. Instead of donations they invite you to Like their Facebook page.
Q. Let’s talk a moment about cryptography and SSL. What is new there?
Ivan Ristic, the author of the book “Bulletproof SSL/TLS”, runs an SSL scoring service over at Qualys SSL Labs. The scoring uses the grading system, A, B, C, D, F, which is nice because I can remember that.
So for the last five years, half the SSL administrator’s I’ve worked with are trying to get an A+ on their website. And it’s not just pride because people are writing articles basically “SSL shaming” entire industries. It started in Australia where Troy Hunt (the owner of the HaveIBeenPwnd website) posted the scores of all the banks in Australia.
But I’ve seen that done in Poland and even here Belgium as well. In the states, someone posted the SSL scores for all of the presidential candidates. Wouldn’t it be cool if that’s how we actually choose our presidential leaders? By their cryptographic security posture? That would be much better than how we’re doing it now, because apparently whatever we are doing isn’t working very well.
Would you like to know what Hillary Clinton gets?
She gets an A, but it’s actually a private server in her laundry room.
Q. What do you see as the most serious security threat?
There are rumors of the Russian’s hacking our election and trying to throw it to Donald Trump. Why they would do this, other than as the ultimate party joke, is sort of beyond me. But it is quite concerning. Security professionals have been warning about the dangers of automated voting systems for years, and I worry that people aren’t taking it as seriously as they should. I would imagine that you’ve been doing it here for years, and it’s working?
But if you meant “what are the most serious threats to the Enterprise” I’d have to say Malware. It has been the number one threat this year, and the last five years running. That’s why FireEye was such a security darling. The biggest problem with malware, at least in the states, is that all the malware authors know that they need to hide their malware inside SSL connections so it won’t be detected.
In the States we can decrypt that traffic (if the customer wants) and clone it over to FireEye or an IDS. You can’t do that in many places here in Europe, and I’m interested to see how that works out. Q. To what extent is IoT the next driver for increased security risks?
Do you know what an oxymoron is? Two words that don’t go together, like ‘military intelligence’ or ‘found missing’ or ‘Microsoft Works’. Well ‘IoT Security’ is like that. It used to be a joke until about 2 weeks ago, when someone launched a 620 Gbps attack using (at least partly) a new IoT botnet. That was the largest DDoS attack I’m aware of, though the record has possibly been broken since then.
Most IoT devices connect one-way up to a cloud module, so that’s good. I think IoT security is going to be a huge issue for a long, long time because that’s basically a brand new industry. I mean, the Internet has been around for 30 years and it’s still far from secure even with every researcher in the world trying to fix it, so why would anyone assume the IoT universe won’t be anything but suboptimal?
I think for Europe this is a real challenge and opportunity. Germany is still the economic powerhouse of Europe, and they rely on manufacturing. They absolutely have to get IoT security right as they build their internet-connected cars and airplane engines.
Q. How can do you provide protection against multi-faceted DDoS attacks?
I just wrote a whitepaper called the 2016 DDoS Trend analysis, and buried within that paper are 8 references to Huey Lewis. I mention that because no one has been able to locate them all yet and I have gift card I need to give away.
But in our paper we note that we now see the majority of DDoS attacks as comprising multiple attack vectors and they’re getting more sophisticated, too. For example, stateful TCP floods are way up, and on some days they are outnumbering stupid UDP floods.
So we have some customers who don’t want to deal with any of it at all and just contract us to handle all their attacks for them 24/7. But many other customers are going for a blend of cloud-protection and on-premises DDoS.
For on-premises, if you have an F5, there’s a LOT you can do. We have a best practices document that shows you how to handle every DDoS attack type we’ve ever seen. Just google ‘David Holmes DDoS Recommended Practices’ and you’ll find it.
Q. Looking in a crystal ball, where do you think the security threats will come from in 5 to 10 years?
First, let me say that I think people are terrible at predicting the future. Just awful. With that said, let me um, try to predict the future.
I think finding sufficient entropy will continue to be a source of frustration among security professionals. Computers today are awful at getting real random data from which to generate keys or other cryptographic material, so everyone cheats at this. Professor Nadia Heninger from the University of Michigan has done some amazing work here [talk a little about her work]
Time synchronization is going to be another sore point. Real authentication and authorization systems require at least some kind of crude but secure time synchronization. The Internet has always been terrible about this so both Microsoft and Google are coming up with their own secure time mechanisms.
Lastly, as I get older, I am really hopeful that we will achieve The Singularity before I expire.
In this piece, yours truly evaluates the SWEET32 cryptographic attack relative to other SSL cryptographic attacks such as DROWN and BEAST.
Here's an awesome whitepaper I wrote in the fall of 2016. I embedded eight references to Huey Lewis and the News. Can you find them all?
I've been coming to this hacker con since Defcon 7. So that's 17 years! DC24 was a good one, with some interesting talks. Here's a recap I did for SecurityWeek.
Here's a recap I did for SecurityWeek of some of the more interesting talks at the 2016 Black Hat security conference.
F5 commissioned the analyst firm IDC to survey hundreds of infosec professionals. The goal was to find out exactly how much enterprise traffic is encrypted. Their answers? Between 25-50% in 2016. That's a lot! Read the survey to find out how infosec is dealing with all the encrypted traffic, and the malware that hides within.
I heard about this problem with a customer in Oslo, Norway. It has to do with an advance in cryptography throwing surveillance devices into darkness.
I get lucky sometimes. This was one of those times. I ran into a member of CERT.be, and he told me of an interesting report about a cyberespinage case in Europe. Made for a great SecurityWeek article.
I’ve just returned from a long tour of Australia and New Zealand (ANZ), where some exciting developments are worth capturing. Both countries are island nations, and one thing Darwin noted in “On the Origin of Species” is that islands can become crucibles of evolution. Australia is evolving a new way to leverage cloud, and New Zealand is evolving a new efficiency model for government security services. Both countries share one aspect with the rest of the world: challenges around encryption.
After I came back from my 50 days in Asia, I wrote up three observations about how infosec is different there. Some good analogies. Kinda proud of this piece.
When asked for Comment on the Panama papers, I said heck yeah, there are so many questions. So I put them into a SecurityWeek byline, and then answered them. Most of them. Even the one about Simon Cowell.
A SecurityWeek article quotes me about SSLv3 and RC4.
A look at how a Dridex malware campaign is shifting around the globe.
A SecurityWeek article quotes me about breaches.
A SecurityWeek article quotes me about the Open CA "Let's Encrypt"
During my last visit to Australia, I talked with some customers who were running into some fascinating problems trying to secure multiple components across different public clouds. Wrote it up for SecurityWeek.
A piece written from an interview I did while in Australia. I remember doing this interview from the passenger seat of David Arthur's car while we were driving to lunch in Canberra. The things you remember.
Should you panic about the DROWN SSL vulnerability? Is it cute and kid-friendly, or is it a monster vulnerability coming to expose your most sensitive data? This piece I did for SecurityWeek builds upon the "Stack Ranking SSL Vulnerabilities" article I'd written the year before.
THE Richard Chirgwin of the Register once interviewed me while I was deliriously excited after talking with some customers in Australia. I gave a wide-ranging interview on all kinds of topics, stuff was just coming out of my mouth. Richard loved it. Later he told my bosses "this was the perfect interview - exactly what I want to hear when I talk with people in the industry!"
Not every day you get on the front page of the local paper! Was in the Philippines immediately after the first SWIFT banking theft: $81M had been stolen (by the Lazarus group, probably) and laundered through local casinos. I happened to be there speaking with the media about bank fraud anyway, so that's how country manager Oscar Visaya and I ended up on the front page of the paper.
SecurityWeek quotes me about strict transport security.
A great piece that came from looking at how the different top tier analysts look at the discipline of Application Security.
The idea for this, my favorite article, had been rattling around my head for years. "Why don't you use your knowledge for evil?" I surveyed over three dozen of my friends and colleagues to find out what their prices were, if any. Some illuminating results.
I know it sounds like I pick on Let's Encrypt, the free, open CA. And I guess I do kinda. Not in a mean way, because what they are doing is pretty freaking cool. But in a skeptical way, because so often the road to hell is paved with good intentions. On the other hand, there are altruistic endeavors that I would have said would never work, like Wikipedia, and um, well that's about it. Anyway, this piece is a more measured look at the early public stages of Let's Encrypt.
F5 Network security evangelist David Holmes offers concrete advice about how cloud outsourcing can help companies with a talent shortfall solve three enterprise security problems: application security, penetration testing, and bug bounties.
SecurityWeek article quotes me about my favorite algorithm of all time, RC4.
A look back at the mega breaches of 2015: Ashley Madison, the OPM hack, Kaspersky, and more.
Here's the complete list of everything authored by yours truly in 2015. Except the NC-17 stuff, which I've been told should remain unpromoted. Actually, this website you're reading right now is basically my greatest hits, but this blog post gather just a single, awesome year of it.
A cute little piece celebrating the new year, infosec style.
This is is one of my favorite articles. There was a crazy rumor going around after the Paris attacks that the terrorists were using Sony PlayStations to communicate with each other. And that the PS4 encryption was hiding their communications from Europol. So I decided to find out what kind encryption the PS4 uses. And how resistant would it be to surveillance.
East-west data center traffic needs to be secured. Here's the easy way to do it with the load balancers you already have.
SecurityWeek article quotes me about entropy.
My love letter to my favorite algorithm of all time, RC4.
Strict Transport Security is a simple but very powerful security fix. So why does no-one use it? I explore the topic in this piece for SecurityWeek.
My third piece in the trilogy of articles I've written about the open CA "Let's Encrypt" for SecurityWeek. This one is a more measured look at how LE might impact Internet Security.
A mention in SecurityWeek article about container security.
When the POODLE vulnerability came out in 2014, it was hailed as the death knell for SSL version 3. In the quarter just prior to POODLE, 98% of Internet sites supported SSLv3, but a year later that support had dropped to just 33%. Here's an article that shows you how to tell how much of your traffic is still SSLv3.
A BGP route monitoring firm, Qrator, released a paper at Blackhat 2015 titled “Breaking HTTPS with BGP Hijacking.” Here's my take on it.
Cryptography has been a passion of mine since I was 9. NINE. I used to write code books to encrypt messages as a kid. So of course I gravitated to internet encryption, and spent a lot of time working with the Secure Sockets Library (SSL), which is now TLS. Here's a 50+ page magnum opus I wrote about the proper ways to use F5's SSL capabilities. Great stuff in here.
Not all SSL vulnerabilities are the same. Some are way worse than others, but often the media doesn't know that. My attempt to provide a relative scale based on quantifiable cryptographic assets. Also uses a cute Japanese Monster Alert level.
I first ran into the hacker search Shodan engine at Defcon over a decade ago. It's still around; I saw its creator, John Matherly, giving a talk about it in Amsterdam's Hack-in-the-Box conference. My summary for SecurityWeek.
An in-depth piece about the SSL Logjam vulnerability. How vulnerable are you, and here's how to mitigate it if you are.
A deeper dive in to the theoretical topic of mobile malware.
TechWeekEurope's Michael Moore speaks to David Holmes, Senior Security Evangelist for F5 Networks, at InfoSecurity Europe 2015
It takes effort to stay informed about the information security industry. The #infosec landscape changes incredibly fast. Security researchers and adversarial attackers generate a constant stream of vulnerabilities and other threat vectors. Keeping abreast of it all is a constant challenge. One great way to stay informed is to listen to a selection of security-themed podcasts. Podcasts keep your brain engaged when you’re multitasking some menial physical task like cleaning or driving or walking Roy, the Wonder Dog. Here are three security-themed podcasts that provide a pulse on infosec.
I won a long-standing bet with my colleague, Pete Silva, about the Android Armageddon. Here's my write-up where I claim to win!
In 1897, physiologist René Quinton completely replaced the blood of a live, abandoned dog with seawater in an experiment to prove the theory that the chemistry of mammalian blood is formulated from ocean water, with which it shares many properties including salinity and acidity. Sound interesting? It is! A friend of mine called me recently: "Hey man, I was looking up the security of docker containers and read this article and lo-and-behold it was my old buddy Dave who wrote it!"
F5 launched a new web application firewall (WAF) in the cloud service. Here's my take on why it will succeed.
Three different reasons why tractor companies find themselves in the crosshairs of DDoS attackers.
A deeper look into the security skills shortage. What can be done?
I was born to write this article. It was floating around in my head for years and years, and finally came together. I've delivered a talk about the topic of RNG to dozens of audiences around the world, and the best parts of that talk are summarized in this SecurityWeek piece.
This is wicked important, and you should read it right now. This could improve your entire cryptographic security posture. For free. You're welcome!
One of my favorite pieces, and one of the most high-profile as well. Lots of great discussion around this.
Here's a whitepaper I did on the expectation of SSL everywhere and what it means for business today. Topics covered include Forward Secrecy, Privacy, advanced key management and how to protect everything with an "always on" architecture.
An article I did for DataCenterKnowledge. A look back at 2014 and all the ShellShock and Heartbleed fallout for Data Center Knowledge. Nice, crisp piece. License for the xkcd image: https://xkcd.com/license.html
This is the most-read article I've ever written. A true-story about a cyberattack that supposedly involved the nude pictures of Jennifer Lawrence and Kate Upton.
Here's an article where I compare Bitcoin (and other blockchain fintech) to another virtual currency, the one promoted and used by tens of millions in Africa: m-pesa.
I still get questions about this SecurityWeek piece, which is good because I'm quite proud of this one. It's a look at three different systems that tried to patch one of the nagging security "holes" in the Internet and why they all failed.
"The giraffe was probably dead." LOL that is the best line I've ever used to start an article. This SecurityWeek piece about Twitter security came out of a trip I did to Africa.
The reputation of IP addresses is can be used to create intelligent security controls. Here's a white paper for how to leverage that control.
Caught between high-profile security breaches, APTs, and “millennial” employees who expect 24/7 Internet access, forward-looking IT organizations can consolidate web access and security into a highperformance, strategic point of control: F5 Secure Web Gateway Services.
After many discussions with some of the most high profile brands in the world, I've consolidated their feedback into this single playbook. These are the ten steps you need to do when you get attacked with a distributed denial-of-service. It's basically vendor agnostic, with just the F5 logo on it.
This is almost top secret stuff. I probably shouldn't even be writing about it, but other's have, so if someone were to weaponize this, well I can't be held responsible. And at least I provided a defense.
As you would imagine, being a security and networking professional, I ran a pretty sophisticated home network. One time I plugged our partner Webroot's IP reputation tool in front of my home router to see what kind of malicious traffic it was flagging. Here are the results.
I wrote a piece about the UDP-based distributed denial of service (DDoS) attack involving Spamhaus and CyberBunker. It was published in ComputerWorld in 2013.
Here's a great paper I wrote about how to categorize different DDoS attacks by type and by threat. Not a lot of discussion about mitigation, just classification and examination of the different attacks.
Written in 2012, this was a new way to think about Data Center Firewalls. Written with the amazing Lori MacVittie.