Entries Tagged "academic papers"

Page 56 of 86

Security Vulnerabilities of Legacy Code

An interesting research paper documents a “honeymoon effect” when it comes to software and vulnerabilities: attackers are more likely to find vulnerabilities in older and more familiar code. It’s a few years old, but I haven’t seen it before now. The paper is by Sandy Clark, Stefan Frei, Matt Blaze, and Jonathan Smith: “Familiarity Breeds Contempt: The Honeymoon Effect and the Role of Legacy Code in Zero-Day Vulnerabilities,” Annual Computer Security Applications Conference 2010.

Abstract: Work on security vulnerabilities in software has primarily focused on three points in the software life-cycle: (1) finding and removing software defects, (2) patching or hardening software after vulnerabilities have been discovered, and (3) measuring the rate of vulnerability exploitation. This paper examines an earlier period in the software vulnerability life-cycle, starting from the release date of a version through to
the disclosure of the fourth vulnerability, with a particular focus on the time from release until the very first disclosed vulnerability.

Analysis of software vulnerability data, including up to a decade of data for several versions of the most popular operating systems, server applications and user applications (both open and closed source), shows that properties extrinsic to the software play a much greater role in the rate of vulnerability discovery than do intrinsic properties such as software quality. This leads us to the observation that (at least in the first phase of a product’s existence), software vulnerabilities have different properties from software defects.

We show that the length of the period after the release of a software product (or version) and before the discovery of the first vulnerability (the ‘Honeymoon’ period) is primarily a function of familiarity with the system. In addition, we demonstrate that legacy code resulting from code re-use is a major contributor to both the rate of vulnerability discovery and the numbers of vulnerabilities found; this has significant implications for software engineering principles and practice.

Posted on December 17, 2013 at 7:10 AM • View Comments

More on Stuxnet

Ralph Langer has written the definitive analysis of Stuxnet: short, popular version, and long, technical version.

Stuxnet is not really one weapon, but two. The vast majority of the attention has been paid to Stuxnet’s smaller and simpler attack routine—the one that changes the speeds of the rotors in a centrifuge, which is used to enrich uranium. But the second and “forgotten” routine is about an order of magnitude more complex and stealthy. It qualifies as a nightmare for those who understand industrial control system security. And strangely, this more sophisticated attack came first. The simpler, more familiar routine followed only years later—and was discovered in comparatively short order.

Also:

Stuxnet also provided a useful blueprint to future attackers by highlighting the royal road to infiltration of hard targets. Rather than trying to infiltrate directly by crawling through 15 firewalls, three data diodes, and an intrusion detection system, the attackers acted indirectly by infecting soft targets with legitimate access to ground zero: contractors. However seriously these contractors took their cybersecurity, it certainly was not on par with the protections at the Natanz fuel-enrichment facility. Getting the malware on the contractors’ mobile devices and USB sticks proved good enough, as sooner or later they physically carried those on-site and connected them to Natanz’s most critical systems, unchallenged by any guards.

Any follow-up attacker will explore this infiltration method when thinking about hitting hard targets. The sober reality is that at a global scale, pretty much every single industrial or military facility that uses industrial control systems at some scale is dependent on its network of contractors, many of which are very good at narrowly defined engineering tasks, but lousy at cybersecurity. While experts in industrial control system security had discussed the insider threat for many years, insiders who unwittingly helped deploy a cyberweapon had been completely off the radar. Until Stuxnet.

And while Stuxnet was clearly the work of a nation-state—requiring vast resources and considerable intelligence—future attacks on industrial control and other so-called “cyber-physical” systems may not be. Stuxnet was particularly costly because of the attackers’ self-imposed constraints. Damage was to be disguised as reliability problems. I estimate that well over 50 percent of Stuxnet’s development cost went into efforts to hide the attack, with the bulk of that cost dedicated to the overpressure attack which represents the ultimate in disguise—at the cost of having to build a fully-functional mockup IR-1 centrifuge cascade operating with real uranium hexafluoride. Stuxnet-inspired attackers will not necessarily place the same emphasis on disguise; they may want victims to know that they are under cyberattack and perhaps even want to publicly claim credit for it.

Related: earlier this month, Eugene Kaspersky said that Stuxnet also damaged a Russian nuclear power station and the International Space Station.

Posted on November 29, 2013 at 6:18 AM • View Comments

Cognitive Biases About Violence as a Negotiating Tactic

Interesting paper: Max Abrahms, “The Credibility Paradox: Violence as a Double-Edged Sword in International Politics,” International Studies Quarterly, 2013:

Abstract: Implicit in the rationalist literature on bargaining over the last half-century is the political utility of violence. Given our anarchical international system populated with egoistic actors, violence is thought to promote concessions by lending credibility to their threats. From the vantage of bargaining theory, then, empirical research on terrorism poses a puzzle. For non-state actors, terrorism signals a credible threat in comparison to less extreme tactical alternatives. In recent years, however, a spate of studies across disciplines and methodologies has nonetheless found that neither escalating to terrorism nor with terrorism encourages government concessions. In fact, perpetrating terrorist acts reportedly lowers the likelihood of government compliance, particularly as the civilian casualties rise. The apparent tendency for this extreme form of violence to impede concessions challenges the external validity of bargaining theory, as traditionally understood. In this study, I propose and test an important psychological refinement to the standard rationalist narrative. Via an experiment on a national sample of adults, I find evidence of a newfound cognitive heuristic undermining the coercive logic of escalation enshrined in bargaining theory. Due to this oversight, mainstream bargaining theory overestimates the political utility of violence, particularly as an instrument of coercion.

Posted on October 25, 2013 at 6:30 AM • View Comments

SecureDrop

SecureDrop is an open-source whistleblower support system, originally written by Aaron Swartz and now run by the Freedom of the Press Foundation. The first instance of this system was named StrongBox and is being run by The New Yorker. To further add to the naming confusion, Aaron Swartz called the system DeadDrop when he wrote the code.

I participated in a detailed security audit of the StrongBox implementation, along with some great researchers from the University of Washington and Jake Applebaum. The problems we found were largely procedural, and things that the Freedom of the Press Foundation are working to fix.

Freedom of the Press Foundation is not running any instances of SecureDrop. It has about a half dozen major news organization lined up, and will be helping them install their own starting the first week of November. So hopefully any would-be whistleblowers will soon have their choice of news organizations to securely communicate with.

Strong technical whistleblower protection is essential, especially given President Obama’s war on whistleblowers. I hope this system is broadly implemented and extensively used.

Posted on October 17, 2013 at 7:15 AM • View Comments

Massive MIMO Cryptosystem

New paper: “Physical-Layer Cryptography Through Massive MIMO.”

Abstract: We propose the new technique of physical-layer cryptography based on using a massive MIMO channel as a key between the sender and desired receiver, which need not be secret. The goal is for low-complexity encoding and decoding by the desired transmitter-receiver pair, whereas decoding by an eavesdropper is hard in terms of prohibitive complexity. The decoding complexity is analyzed by mapping the massive MIMO system to a lattice. We show that the eavesdropper’s decoder for the MIMO system with M-PAM modulation is equivalent to solving standard lattice problems that are conjectured to be of exponential complexity for both classical and quantum computers. Hence, under the widely-held conjecture that standard lattice problems are hard to solve in the worst-case, the proposed encryption scheme has a more robust notion of security than that of the most common encryption methods used today such as RSA and Diffie-Hellman. Additionally, we show that this scheme could be used to securely communicate without a pre-shared secret and little computational overhead. Thus, the massive MIMO system provides for low-complexity encryption commensurate with the most sophisticated forms of application-layer encryption by exploiting the physical layer properties of the radio channel.

MIMO stands for “multiple-input multiple-output.” I had to look that up.

In general, I’m not optimistic about the security of these sorts of systems. Whenever non-cryptographers come up with cryptographic algorithms based on some novel problem that’s hard in their area of research, invariably there are pretty easy cryptographic attacks.

So consider this a good research exercise for all budding cryptanalysts out there.

Posted on October 15, 2013 at 6:27 AM • View Comments

Insecurities in the Linux /dev/random

New paper: “Security Analysis of Pseudo-Random Number Generators with Input: /dev/random is not Robust, by Yevgeniy Dodis, David Pointcheval, Sylvain Ruhault, Damien Vergnaud, and Daniel Wichs.

Abstract: A pseudo-random number generator (PRNG) is a deterministic algorithm that produces numbers whose distribution is indistinguishable from uniform. A formal security model for PRNGs with input was proposed in 2005 by Barak and Halevi (BH). This model involves an internal state that is refreshed with a (potentially biased) external random source, and a cryptographic function that outputs random numbers from the continually internal state. In this work we extend the BH model to also include a new security property capturing how it should accumulate the entropy of the input data into the internal state after state compromise. This property states that a good PRNG should be able to eventually recover from compromise even if the entropy is injected into the system at a very slow pace, and expresses the real-life expected behavior of existing PRNG designs. Unfortunately, we show that neither the model nor the specific PRNG construction proposed by Barak and Halevi meet this new property, despite meeting a weaker robustness notion introduced by BH. From a practical side, we also give a precise assessment of the security of the two Linux PRNGs, /dev/random and /dev/urandom. In particular, we show several attacks proving that these PRNGs are not robust according to our definition, and do not accumulate entropy properly. These attacks are due to the vulnerabilities of the entropy estimator and the internal mixing function of the Linux PRNGs. These attacks against the Linux PRNG show that it does not satisfy the “robustness” notion of security, but it remains unclear if these attacks lead to actual exploitable vulnerabilities in practice. Finally, we propose a simple and very efficient PRNG construction that is provably robust in our new and stronger adversarial model. We present benchmarks between this construction and the Linux PRNG that show that this construction is on average more efficient when recovering from a compromised internal state and when generating cryptographic keys. We therefore recommend to use this construction whenever a PRNG with input is used for cryptography.

Posted on October 14, 2013 at 1:06 PM • View Comments

Is Cybersecurity a Profession?

A National Academy of Sciences panel says no:

Sticking to the quality control aspect of the report, professionalization, it says, has the potential to attract workers and establish long-term paths to improving the work force overall, but measures such as standardized education or requirements for certification, have their disadvantages too.

For example, formal education or certification could be helpful to employers looking to evaluate the skills and knowledge of a given applicant, but it takes time to develop curriculum and reach a consensus on what core knowledge and skills should be assessed in order to award any such certification. For direct examples of such a quandary, InfoSec needs only to look at the existing certification programs, and the criticisms directed that certifications such as the CISSP and C|EH.

Once a certification is issued, the previously mentioned barriers start to emerge. The standards used to award certifications will run the risk of becoming obsolete. Furthermore, workers may not have incentives to update their skills in order to remain current. Again, this issue is seen in the industry today, as some professionals chose to let their certifications lapse rather than renew them or try and collect the required CPE credits.

But the largest barrier is that some of the most talented individuals in cybersecurity are self-taught. So the requirement of formal education or training may, as mentioned, deter potential employees from entering the field at a time when they are needed the most. So while professionalization may be a useful tool in some circumstances, the report notes, it shouldn’t be used as a proxy for “better.”

Here’s the report.

Posted on October 3, 2013 at 12:55 PM • View Comments

On Anonymous

Gabriella Coleman has published an interesting analysis of the hacker group Anonymous:

Abstract: Since 2010, digital direct action, including leaks, hacking and mass protest, has become a regular feature of political life on the Internet. The source, strengths and weakness of this activity are considered in this paper through an in-depth analysis of Anonymous, the protest ensemble that has been adept at magnifying issues, boosting existing ­ usually oppositional ­ movements and converting amorphous discontent into a tangible form. This paper, the third in the Internet Governance Paper Series, examines the intersecting elements that contribute to Anonymous’ contemporary geopolitical power: its ability to land media attention, its bold and recognizable aesthetics, its participatory openness, the misinformation that surrounds it and, in particular, its unpredictability.

Posted on October 3, 2013 at 6:43 AM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.