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Last week, I posted a short memorial of Ross Anderson. The Communications of the ACM asked me to expand it. Here’s the longer version.
EDITED TO ADD (4/11): Two weeks before he passed away, Ross gave an 80-minute interview where he told his life story.
The cybersecurity world got really lucky last week. An intentionally placed backdoor in XZ Utils, an open-source compression utility, was pretty much accidentally discovered by a Microsoft engineer—weeks before it would have been incorporated into both Debian and Red Hat Linux. From ArsTehnica:
Malicious code added to XZ Utils versions 5.6.0 and 5.6.1 modified the way the software functions. The backdoor manipulated sshd, the executable file used to make remote SSH connections. Anyone in possession of a predetermined encryption key could stash any code of their choice in an SSH login certificate, upload it, and execute it on the backdoored device. No one has actually seen code uploaded, so it’s not known what code the attacker planned to run. In theory, the code could allow for just about anything, including stealing encryption keys or installing malware.
It was an incredibly complex backdoor. Installing it was a multi-year process that seems to have involved social engineering the lone unpaid engineer in charge of the utility. More from ArsTechnica:
In 2021, someone with the username JiaT75 made their first known commit to an open source project. In retrospect, the change to the libarchive project is suspicious, because it replaced the safe_fprint function with a variant that has long been recognized as less secure. No one noticed at the time.
The following year, JiaT75 submitted a patch over the XZ Utils mailing list, and, almost immediately, a never-before-seen participant named Jigar Kumar joined the discussion and argued that Lasse Collin, the longtime maintainer of XZ Utils, hadn’t been updating the software often or fast enough. Kumar, with the support of Dennis Ens and several other people who had never had a presence on the list, pressured Collin to bring on an additional developer to maintain the project.
There’s a lot more. The sophistication of both the exploit and the process to get it into the software project scream nation-state operation. It’s reminiscent of Solar Winds, although (1) it would have been much, much worse, and (2) we got really, really lucky.
I simply don’t believe this was the only attempt to slip a backdoor into a critical piece of Internet software, either closed source or open source. Given how lucky we were to detect this one, I believe this kind of operation has been successful in the past. We simply have to stop building our critical national infrastructure on top of random software libraries managed by lone unpaid distracted—or worse—individuals.
Ross Anderson unexpectedly passed away Thursday night in, I believe, his home in Cambridge.
I can’t remember when I first met Ross. Of course it was before 2008, when we created the Security and Human Behavior workshop. It was well before 2001, when we created the Workshop on Economics and Information Security. (Okay, he created both—I helped.) It was before 1998, when we wrote about the problems with key escrow systems. I was one of the people he brought to the Newton Institute, at Cambridge University, for the six-month cryptography residency program he ran (I mistakenly didn’t stay the whole time)—that was in 1996.
I know I was at the first Fast Software Encryption workshop in December 1993, another conference he created. There I presented the Blowfish encryption algorithm. Pulling an old first-edition of Applied Cryptography (the one with the blue cover) down from the shelf, I see his name in the acknowledgments. Which means that sometime in early 1993—probably at Eurocrypt in Lofthus, Norway—I, as an unpublished book author who had only written a couple of crypto articles for Dr. Dobb’s Journal, asked him to read and comment on my book manuscript. And he said yes. Which means I mailed him a paper copy. And he read it. And mailed his handwritten comments back to me. In an envelope with stamps. Because that’s how we did it back then.
I have known Ross for over thirty years, as both a colleague and a friend. He was enthusiastic, brilliant, opinionated, articulate, curmudgeonly, and kind. Pick up any of his academic papers—there are many—and odds are that you will find a least one unexpected insight. He was a cryptographer and security engineer, but also very much a generalist. He published on block cipher cryptanalysis in the 1990s, and the security of large-language models last year. He started conferences like nobody’s business. His masterwork book, Security Engineering—now in its third edition—is as comprehensive a tome on cybersecurity and related topics as you could imagine. (Also note his fifteen-lecture video series on that same page. If you have never heard Ross lecture, you’re in for a treat.) He was the first person to understand that security problems are often actually economic problems. He was the first person to make a lot of those sorts of connections. He fought against surveillance and backdoors, and for academic freedom. He didn’t suffer fools in either government or the corporate world.
He’s listed in the acknowledgments as a reader of every one of my books from Beyond Fear on. Recently, we’d see each other a couple of times a year: at this or that workshop or event. The last time I saw him was last June, at SHB 2023, in Pittsburgh. We were having dinner on Alessandro Acquisti‘s rooftop patio, celebrating another successful workshop. He was going to attend my Workshop on Reimagining Democracy in December, but he had to cancel at the last minute. (He sent me the talk he was going to give. I will see about posting it.) The day before he died, we were discussing how to accommodate everyone who registered for this year’s SHB workshop. I learned something from him every single time we talked. And I am not the only one.
My heart goes out to his wife Shireen and his family. We lost him much too soon.
EDITED TO ADD (4/10): I wrote a longer version for Communications of the ACM.
EDITED TO ADD (4/11): Two weeks before he passed away, Ross gave an 80-minute interview where he told his life story.
It’s pretty devastating:
Today, Ian Carroll, Lennert Wouters, and a team of other security researchers are revealing a hotel keycard hacking technique they call Unsaflok. The technique is a collection of security vulnerabilities that would allow a hacker to almost instantly open several models of Saflok-brand RFID-based keycard locks sold by the Swiss lock maker Dormakaba. The Saflok systems are installed on 3 million doors worldwide, inside 13,000 properties in 131 countries. By exploiting weaknesses in both Dormakaba’s encryption and the underlying RFID system Dormakaba uses, known as MIFARE Classic, Carroll and Wouters have demonstrated just how easily they can open a Saflok keycard lock. Their technique starts with obtaining any keycard from a target hotel—say, by booking a room there or grabbing a keycard out of a box of used ones—then reading a certain code from that card with a $300 RFID read-write device, and finally writing two keycards of their own. When they merely tap those two cards on a lock, the first rewrites a certain piece of the lock’s data, and the second opens it.
Dormakaba says that it’s been working since early last year to make hotels that use Saflok aware of their security flaws and to help them fix or replace the vulnerable locks. For many of the Saflok systems sold in the last eight years, there’s no hardware replacement necessary for each individual lock. Instead, hotels will only need to update or replace the front desk management system and have a technician carry out a relatively quick reprogramming of each lock, door by door. Wouters and Carroll say they were nonetheless told by Dormakaba that, as of this month, only 36 percent of installed Safloks have been updated. Given that the locks aren’t connected to the internet and some older locks will still need a hardware upgrade, they say the full fix will still likely take months longer to roll out, at the very least. Some older installations may take years.
If ever. My guess is that for many locks, this is a permanent vulnerability.
Andrew Appel shepherded a public comment—signed by twenty election cybersecurity experts, including myself—on best practices for ballot marking devices and vote tabulation. It was written for the Pennsylvania legislature, but it’s general in nature.
From the executive summary:
We believe that no system is perfect, with each having trade-offs. Hand-marked and hand-counted ballots remove the uncertainty introduced by use of electronic machinery and the ability of bad actors to exploit electronic vulnerabilities to remotely alter the results. However, some portion of voters mistakenly mark paper ballots in a manner that will not be counted in the way the voter intended, or which even voids the ballot. Hand-counts delay timely reporting of results, and introduce the possibility for human error, bias, or misinterpretation.
Technology introduces the means of efficient tabulation, but also introduces a manifold increase in complexity and sophistication of the process. This places the understanding of the process beyond the average person’s understanding, which can foster distrust. It also opens the door to human or machine error, as well as exploitation by sophisticated and malicious actors.
Rather than assert that each component of the process can be made perfectly secure on its own, we believe the goal of each component of the elections process is to validate every other component.
Consequently, we believe that the hallmarks of a reliable and optimal election process are hand-marked paper ballots, which are optically scanned, separately and securely stored, and rigorously audited after the election but before certification. We recommend state legislators adopt policies consistent with these guiding principles, which are further developed below.
C++ guru Herb Sutter writes about how we can improve the programming language for better security.
The immediate problem “is” that it’s Too Easy By Default™ to write security and safety vulnerabilities in C++ that would have been caught by stricter enforcement of known rules for type, bounds, initialization, and lifetime language safety.
His conclusion:
We need to improve software security and software safety across the industry, especially by improving programming language safety in C and C++, and in C++ a 98% improvement in the four most common problem areas is achievable in the medium term. But if we focus on programming language safety alone, we may find ourselves fighting yesterday’s war and missing larger past and future security dangers that affect software written in any language.
NIST has released version 2.0 of the Cybersecurity Framework:
The CSF 2.0, which supports implementation of the National Cybersecurity Strategy, has an expanded scope that goes beyond protecting critical infrastructure, such as hospitals and power plants, to all organizations in any sector. It also has a new focus on governance, which encompasses how organizations make and carry out informed decisions on cybersecurity strategy. The CSF’s governance component emphasizes that cybersecurity is a major source of enterprise risk that senior leaders should consider alongside others such as finance and reputation.
[…]
The framework’s core is now organized around six key functions: Identify, Protect, Detect, Respond and Recover, along with CSF 2.0’s newly added Govern function. When considered together, these functions provide a comprehensive view of the life cycle for managing cybersecurity risk.
The updated framework anticipates that organizations will come to the CSF with varying needs and degrees of experience implementing cybersecurity tools. New adopters can learn from other users’ successes and select their topic of interest from a new set of implementation examples and quick-start guides designed for specific types of users, such as small businesses, enterprise risk managers, and organizations seeking to secure their supply chains.
This is a big deal. The CSF is widely used, and has been in need of an update. And NIST is exactly the sort of respected organization to do this correctly.
Good essay on software bloat and the insecurities it causes.
The world ships too much code, most of it by third parties, sometimes unintended, most of it uninspected. Because of this, there is a huge attack surface full of mediocre code. Efforts are ongoing to improve the quality of code itself, but many exploits are due to logic fails, and less progress has been made scanning for those. Meanwhile, great strides could be made by paring down just how much code we expose to the world. This will increase time to market for products, but legislation is around the corner that should force vendors to take security more seriously.
Over on Lawfare, Jim Dempsey published a really interesting proposal for software liability: “Standard for Software Liability: Focus on the Product for Liability, Focus on the Process for Safe Harbor.”
Section 1 of this paper sets the stage by briefly describing the problem to be solved. Section 2 canvasses the different fields of law (warranty, negligence, products liability, and certification) that could provide a starting point for what would have to be legislative action establishing a system of software liability. The conclusion is that all of these fields would face the same question: How buggy is too buggy? Section 3 explains why existing software development frameworks do not provide a sufficiently definitive basis for legal liability. They focus on process, while a liability regime should begin with a focus on the product—that is, on outcomes. Expanding on the idea of building codes for building code, Section 4 shows some examples of product-focused standards from other fields. Section 5 notes that already there have been definitive expressions of software defects that can be drawn together to form the minimum legal standard of security. It specifically calls out the list of common software weaknesses tracked by the MITRE Corporation under a government contract. Section 6 considers how to define flaws above the minimum floor and how to limit that liability with a safe harbor.
Full paper here.
Dempsey basically creates three buckets of software vulnerabilities: easy stuff that the vendor should have found and fixed, hard-to-find stuff that the vendor couldn’t be reasonably expected to find, and the stuff in the middle. He draws from other fields—consumer products, building codes, automobile design—to show that courts can deal with the stuff in the middle.
I have long been a fan of software liability as a policy mechanism for improving cybersecurity. And, yes, software is complicated, but we shouldn’t let the perfect be the enemy of the good.
In 2003, I wrote:
Clearly this isn’t all or nothing. There are many parties involved in a typical software attack. There’s the company who sold the software with the vulnerability in the first place. There’s the person who wrote the attack tool. There’s the attacker himself, who used the tool to break into a network. There’s the owner of the network, who was entrusted with defending that network. One hundred percent of the liability shouldn’t fall on the shoulders of the software vendor, just as one hundred percent shouldn’t fall on the attacker or the network owner. But today one hundred percent of the cost falls on the network owner, and that just has to stop.
Courts can adjudicate these complex liability issues, and have figured this thing out in other areas. Automobile accidents involve multiple drivers, multiple cars, road design, weather conditions, and so on. Accidental restaurant poisonings involve suppliers, cooks, refrigeration, sanitary conditions, and so on. We don’t let the fact that no restaurant can possibly fix all of the food-safety vulnerabilities lead us to the conclusion that restaurants shouldn’t be responsible for any food-safety vulnerabilities, yet I hear that line of reasoning regarding software vulnerabilities all of the time.
Sidebar photo of Bruce Schneier by Joe MacInnis.