September 15, 2020

by Bruce Schneier
Fellow and Lecturer, Harvard Kennedy School

A free monthly newsletter providing summaries, analyses, insights, and commentaries on security: computer and otherwise.

For back issues, or to subscribe, visit Crypto-Gram’s web page.

These same essays and news items appear in the Schneier on Security blog, along with a lively and intelligent comment section. An RSS feed is available.

In this issue:

  1. Robocall Results from a Telephony Honeypot
  2. Vaccine for Emotet Malware
  3. Using Disinformation to Cause a Blackout
  4. Copying a Key by Listening to It in Action
  5. Yet Another Biometric: Bioacoustic Signatures
  6. DiceKeys
  7. Identifying People by Their Browsing Histories
  8. Amazon Supplier Fraud
  9. Cory Doctorow on The Age of Surveillance Capitalism
  10. US Postal Service Files Blockchain Voting Patent
  11. Seny Kamara on “Crypto for the People”
  12. North Korea ATM Hack
  13. Insider Attack on the Carnegie Library
  14. 2017 Tesla Hack
  15. Hacking AI-Graded Tests
  16. More on NIST’s Post-Quantum Cryptography
  17. US Space Cybersecurity Directive
  18. The Third Edition of Ross Anderson’s Security Engineering
  19. Ranking National Cyber Power
  20. Interesting Attack on the EMV Smartcard Payment Standard
  21. Upcoming Speaking Engagements

Robocall Results from a Telephony Honeypot

[2020.08.17] A group of researchers set up a telephony honeypot and tracked robocall behavior:

NCSU researchers said they ran 66,606 telephone lines between March 2019 and January 2020, during which time they said to have received 1,481,201 unsolicited calls — even if they never made their phone numbers public via any source.

The research team said they usually received an unsolicited call every 8.42 days, but most of the robocall traffic came in sudden surges they called “storms” that happened at regular intervals, suggesting that robocallers operated using a tactic of short-burst and well-organized campaigns.

In total, the NCSU team said it tracked 650 storms over 11 months, with most storms being of the same size.

Research paper. USENIX talk. Slashdot thread.

Vaccine for Emotet Malware

[2020.08.18] Interesting story of a vaccine for the Emotet malware:

Through trial and error and thanks to subsequent Emotet updates that refined how the new persistence mechanism worked, Quinn was able to put together a tiny PowerShell script that exploited the registry key mechanism to crash Emotet itself.

The script, cleverly named EmoCrash, effectively scanned a user’s computer and generated a correct — but malformed — Emotet registry key.

When Quinn tried to purposely infect a clean computer with Emotet, the malformed registry key triggered a buffer overflow in Emotet’s code and crashed the malware, effectively preventing users from getting infected.

When Quinn ran EmoCrash on computers already infected with Emotet, the script would replace the good registry key with the malformed one, and when Emotet would re-check the registry key, the malware would crash as well, preventing infected hosts from communicating with the Emotet command-and-control server.


The Binary Defense team quickly realized that news about this discovery needed to be kept under complete secrecy, to prevent the Emotet gang from fixing its code, but they understood EmoCrash also needed to make its way into the hands of companies across the world.

Compared to many of today’s major cybersecurity firms, all of which have decades of history behind them, Binary Defense was founded in 2014, and despite being one of the industry’s up-and-comers, it doesn’t yet have the influence and connections to get this done without news of its discovery leaking, either by accident or because of a jealous rival.

To get this done, Binary Defense worked with Team CYMRU, a company that has a decades-long history of organizing and participating in botnet takedowns.

Working behind the scenes, Team CYMRU made sure that EmoCrash made its way into the hands of national Computer Emergency Response Teams (CERTs), which then spread it to the companies in their respective jurisdictions.

According to James Shank, Chief Architect for Team CYMRU, the company has contacts with more than 125 national and regional CERT teams, and also manages a mailing list through which it distributes sensitive information to more than 6,000 members. Furthermore, Team CYMRU also runs a biweekly group dedicated to dealing with Emotet’s latest shenanigans.

This broad and well-orchestrated effort has helped EmoCrash make its way around the globe over the course of the past six months.


Either by accident or by figuring out there was something wrong in its persistence mechanism, the Emotet gang did, eventually, changed its entire persistence mechanism on Aug. 6 — exactly six months after Quinn made his initial discovery.

EmoCrash may not be useful to anyone anymore, but for six months, this tiny PowerShell script helped organizations stay ahead of malware operations — a truly rare sight in today’s cyber-security field.

Using Disinformation to Cause a Blackout

[2020.08.18] Interesting paper: “How weaponizing disinformation can bring down a city’s power grid“:

Abstract: Social media has made it possible to manipulate the masses via disinformation and fake news at an unprecedented scale. This is particularly alarming from a security perspective, as humans have proven to be one of the weakest links when protecting critical infrastructure in general, and the power grid in particular. Here, we consider an attack in which an adversary attempts to manipulate the behavior of energy consumers by sending fake discount notifications encouraging them to shift their consumption into the peak-demand period. Using Greater London as a case study, we show that such disinformation can indeed lead to unwitting consumers synchronizing their energy-usage patterns, and result in blackouts on a city-scale if the grid is heavily loaded. We then conduct surveys to assess the propensity of people to follow-through on such notifications and forward them to their friends. This allows us to model how the disinformation may propagate through social networks, potentially amplifying the attack impact. These findings demonstrate that in an era when disinformation can be weaponized, system vulnerabilities arise not only from the hardware and software of critical infrastructure, but also from the behavior of the consumers.

I’m not sure the attack is practical, but it’s an interesting idea.

Copying a Key by Listening to It in Action

[2020.08.20] Researchers are using recordings of keys being used in locks to create copies.

Once they have a key-insertion audio file, SpiKey’s inference software gets to work filtering the signal to reveal the strong, metallic clicks as key ridges hit the lock’s pins [and you can hear those filtered clicks online here]. These clicks are vital to the inference analysis: the time between them allows the SpiKey software to compute the key’s inter-ridge distances and what locksmiths call the “bitting depth” of those ridges: basically, how deeply they cut into the key shaft, or where they plateau out. If a key is inserted at a nonconstant speed, the analysis can be ruined, but the software can compensate for small speed variations.

The result of all this is that SpiKey software outputs the three most likely key designs that will fit the lock used in the audio file, reducing the potential search space from 330,000 keys to just three. “Given that the profile of the key is publicly available for commonly used [pin-tumbler lock] keys, we can 3D-print the keys for the inferred bitting codes, one of which will unlock the door,” says Ramesh.

Yet Another Biometric: Bioacoustic Signatures

[2020.08.21] Sound waves through the body are unique enough to be a biometric:

“Modeling allowed us to infer what structures or material features of the human body actually differentiated people,” explains Joo Yong Sim, one of the ETRI researchers who conducted the study. “For example, we could see how the structure, size, and weight of the bones, as well as the stiffness of the joints, affect the bioacoustics spectrum.”


Notably, the researchers were concerned that the accuracy of this approach could diminish with time, since the human body constantly changes its cells, matrices, and fluid content. To account for this, they acquired the acoustic data of participants at three separate intervals, each 30 days apart.

“We were very surprised that people’s bioacoustics spectral pattern maintained well over time, despite the concern that the pattern would change greatly,” says Sim. “These results suggest that the bioacoustics signature reflects more anatomical features than changes in water, body temperature, or biomolecule concentration in blood that change from day to day.”

It’s not great. A 97% accuracy is worse than fingerprints and iris scans, and while they were able to reproduce the biometric in a month it almost certainly changes as we age, gain and lose weight, and so on. Still, interesting.


[2020.08.24] DiceKeys is a physical mechanism for creating and storing a 192-bit key. The idea is that you roll a special set of twenty-five dice, put them into a plastic jig, and then use an app to convert those dice into a key. You can then use that key for a variety of purposes, and regenerate it from the dice if you need to.

This week Stuart Schechter, a computer scientist at the University of California, Berkeley, is launching DiceKeys, a simple kit for physically generating a single super-secure key that can serve as the basis for creating all the most important passwords in your life for years or even decades to come. With little more than a plastic contraption that looks a bit like a Boggle set and an accompanying web app to scan the resulting dice roll, DiceKeys creates a highly random, mathematically unguessable key. You can then use that key to derive master passwords for password managers, as the seed to create a U2F key for two-factor authentication, or even as the secret key for cryptocurrency wallets. Perhaps most importantly, the box of dice is designed to serve as a permanent, offline key to regenerate that master password, crypto key, or U2F token if it gets lost, forgotten, or broken.


Schechter is also building a separate app that will integrate with DiceKeys to allow users to write a DiceKeys-generated key to their U2F two-factor authentication token. Currently the app works only with the open-source SoloKey U2F token, but Schechter hopes to expand it to be compatible with more commonly used U2F tokens before DiceKeys ship out. The same API that allows that integration with his U2F token app will also allow cryptocurrency wallet developers to integrate their wallets with DiceKeys, so that with a compatible wallet app, DiceKeys can generate the cryptographic key that protects your crypto coins too.

Here’s the DiceKeys website and app. Here’s a short video demo. Here’s a longer SOUPS talk.

Preorder a set here.

Note: I am an adviser on the project.

Another news article. Slashdot thread. Hacker News thread. Reddit thread.

Identifying People by Their Browsing Histories

[2020.08.25] Interesting paper: “Replication: Why We Still Can’t Browse in Peace: On the Uniqueness and Reidentifiability of Web Browsing Histories”:

We examine the threat to individuals’ privacy based on the feasibility of reidentifying users through distinctive profiles of their browsing history visible to websites and third parties. This work replicates and extends the 2012 paper Why Johnny Can’t Browse in Peace: On the Uniqueness of Web Browsing History Patterns[48]. The original work demonstrated that browsing profiles are highly distinctive and stable. We reproduce those results and extend the original work to detail the privacy risk posed by the aggregation of browsing histories. Our dataset consists of two weeks of browsing data from ~52,000 Firefox users. Our work replicates the original paper’s core findings by identifying 48,919 distinct browsing profiles, of which 99% are unique. High uniqueness hold seven when histories are truncated to just 100 top sites. We then find that for users who visited 50 or more distinct domains in the two-week data collection period, ~50% can be reidentified using the top 10k sites. Reidentifiability rose to over 80% for users that browsed 150 or more distinct domains. Finally, we observe numerous third parties pervasive enough to gather web histories sufficient to leverage browsing history as an identifier.

One of the authors of the original study comments on the replication.

Amazon Supplier Fraud

[2020.08.26] Interesting story of an Amazon supplier fraud:

According to the indictment, the brothers swapped ASINs for items Amazon ordered to send large quantities of different goods instead. In one instance, Amazon ordered 12 canisters of disinfectant spray costing $94.03. The defendants allegedly shipped 7,000 toothbrushes costing $94.03 each, using the code for the disinfectant spray, and later billed Amazon for over $650,000.

In another instance, Amazon ordered a single bottle of designer perfume for $289.78. In response, according to the indictment, the defendants sent 927 plastic beard trimmers costing $289.79 each, using the ASIN for the perfume. Prosecutors say the brothers frequently shipped and charged Amazon for more than 10,000 units of an item when it had requested fewer than 100. Once Amazon detected the fraud and shut down their accounts, the brothers allegedly tried to open new ones using fake names, different email addresses, and VPNs to obscure their identity.

It all worked because Amazon is so huge that everything is automated.

Cory Doctorow on The Age of Surveillance Capitalism

[2020.08.27] Cory Doctorow has writtten an extended rebuttal of The Age of Surveillance Capitalism by Shoshana Zuboff. He summarized the argument on Twitter.

Shorter summary: it’s not the surveillance part, it’s the fact that these companies are monopolies.

I think it’s both. Surveillance capitalism has some unique properties that make it particularly unethical and incompatible with a free society, and Zuboff makes them clear in her book. But the current acceptance of monopolies in our society is also extremely damaging — which Doctorow makes clear.

US Postal Service Files Blockchain Voting Patent

[2020.08.28] The US Postal Service has filed a patent on a blockchain voting method:

Abstract: A voting system can use the security of blockchain and the mail to provide a reliable voting system. A registered voter receives a computer readable code in the mail and confirms identity and confirms correct ballot information in an election. The system separates voter identification and votes to ensure vote anonymity, and stores votes on a distributed ledger in a blockchain

I wasn’t going to bother blogging this, but I’ve received enough emails about it that I should comment.

As is pretty much always the case, blockchain adds nothing. The security of this system has nothing to do with blockchain, and would be better off without it. For voting in particular, blockchain adds to the insecurity. Matt Blaze is most succinct on that point:

Why is blockchain voting a dumb idea?

Glad you asked.

For starters:

  • It doesn’t solve any problems civil elections actually have.
  • It’s basically incompatible with “software independence”, considered an essential property.
  • It can make ballot secrecy difficult or impossible.

Both Ben Adida and Matthew Green have written longer pieces on blockchain and voting.

News articles.

Seny Kamara on “Crypto for the People”

[2020.08.31] Seny Kamara gave an excellent keynote talk this year at the (online) CRYPTO Conference. He talked about solving real-world crypto problems for marginalized communities around the world, instead of crypto problems for governments and corporations. Well worth watching and listening to.

North Korea ATM Hack

[2020.09.01] The US Cybersecurity and Infrastructure Security Agency (CISA) published a long and technical alert describing a North Korea hacking scheme against ATMs in a bunch of countries worldwide:

This joint advisory is the result of analytic efforts among the Cybersecurity and Infrastructure Security Agency (CISA), the Department of the Treasury (Treasury), the Federal Bureau of Investigation (FBI) and U.S. Cyber Command (USCYBERCOM). Working with U.S. government partners, CISA, Treasury, FBI, and USCYBERCOM identified malware and indicators of compromise (IOCs) used by the North Korean government in an automated teller machine (ATM) cash-out scheme — referred to by the U.S. Government as “FASTCash 2.0: North Korea’s BeagleBoyz Robbing Banks.”

The level of detail is impressive, as seems to be common in CISA’s alerts and analysis reports.

Insider Attack on the Carnegie Library

[2020.09.02] Greg Priore, the person in charge of the rare book room at the Carnegie Library, stole from it for almost two decades before getting caught.

It’s a perennial problem: trusted insiders have to be trusted.

2017 Tesla Hack

[2020.09.03] Interesting story of a class break against the entire Tesla fleet.

Hacking AI-Graded Tests

[2020.09.04] The company Edgenuity sells AI systems for grading tests. Turns out that they just search for keywords without doing any actual semantic analysis.

More on NIST’s Post-Quantum Cryptography

[2020.09.08] Back in July, NIST selected third-round algorithms for its post-quantum cryptography standard.

Recently, Daniel Apon of NIST gave a talk detailing the selection criteria. Interesting stuff.

US Space Cybersecurity Directive

[2020.09.09] The Trump Administration just published “Space Policy Directive – 5“: “Cybersecurity Principles for Space Systems.” It’s pretty general:

Principles. (a) Space systems and their supporting infrastructure, including software, should be developed and operated using risk-based, cybersecurity-informed engineering. Space systems should be developed to continuously monitor, anticipate,and adapt to mitigate evolving malicious cyber activities that could manipulate, deny, degrade, disrupt,destroy, surveil, or eavesdrop on space system operations. Space system configurations should be resourced and actively managed to achieve and maintain an effective and resilient cyber survivability posture throughout the space system lifecycle.

(b) Space system owners and operators should develop and implement cybersecurity plans for their space systems that incorporate capabilities to ensure operators or automated control center systems can retain or recover positive control of space vehicles. These plans should also ensure the ability to verify the integrity, confidentiality,and availability of critical functions and the missions, services,and data they enable and provide.

These unclassified directives are typically so general that it’s hard to tell whether they actually matter.

News article.

The Third Edition of Ross Anderson’s Security Engineering

[2020.09.10] Ross Anderson’s fantastic textbook, Security Engineering, will have a third edition. The book won’t be published until December, but Ross has been making drafts of the chapters available online as he finishes them. Now that the book is completed, I expect the publisher to make him take the drafts off the Internet.

I personally find both the electronic and paper versions to be incredibly useful. Grab an electronic copy now while you still can.

Ranking National Cyber Power

[2020.09.11] Harvard Kennedy School’s Belfer Center published the “National Cyber Power Index 2020: Methodology and Analytical Considerations.” The rankings: 1. US, 2. China, 3. UK, 4. Russia, 5. Netherlands, 6. France, 7. Germany, 8. Canada, 9. Japan, 10. Australia, 11. Israel. More countries are in the document.

We could — and should — argue about the criteria and the methodology, but it’s good that someone is starting this conversation.

Executive Summary: The Belfer National Cyber Power Index (NCPI) measures 30 countries’ cyber capabilities in the context of seven national objectives, using 32 intent indicators and 27 capability indicators with evidence collected from publicly available data.

In contrast to existing cyber related indices, we believe there is no single measure of cyber power. Cyber Power is made up of multiple components and should be considered in the context of a country’s national objectives. We take an all-of-country approach to measuring cyber power. By considering “all-of-country” we include all aspects under the control of a government where possible. Within the NCPI we measure government strategies, capabilities for defense and offense, resource allocation, the private sector, workforce, and innovation. Our assessment is both a measurement of proven power and potential, where the final score assumes that the government of that country can wield these capabilities effectively.

The NCPI has identified seven national objectives that countries pursue using cyber means. The seven objectives are:

  1. Surveilling and Monitoring Domestic Groups;
  2. Strengthening and Enhancing National Cyber Defenses;
  3. Controlling and Manipulating the Information Environment;
  4. Foreign Intelligence Collection for National Security;
  5. Commercial Gain or Enhancing Domestic Industry Growth;
  6. Destroying or Disabling an Adversary’s Infrastructure and Capabilities; and,
  7. Defining International Cyber Norms and Technical Standards.

In contrast to the broadly held view that cyber power means destroying or disabling an adversary’s infrastructure (commonly referred to as offensive cyber operations), offense is only one of these seven objectives countries pursue using cyber means.

Interesting Attack on the EMV Smartcard Payment Standard

[2020.09.14] It’s complicated, but it’s basically a man-in-the-middle attack that involves two smartphones. The first phone reads the actual smartcard, and then forwards the required information to a second phone. That second phone actually conducts the transaction on the POS terminal. That second phone is able to convince the POS terminal to conduct the transaction without requiring the normally required PIN.

From a news article:

The researchers were able to demonstrate that it is possible to exploit the vulnerability in practice, although it is a fairly complex process. They first developed an Android app and installed it on two NFC-enabled mobile phones. This allowed the two devices to read data from the credit card chip and exchange information with payment terminals. Incidentally, the researchers did not have to bypass any special security features in the Android operating system to install the app.

To obtain unauthorized funds from a third-party credit card, the first mobile phone is used to scan the necessary data from the credit card and transfer it to the second phone. The second phone is then used to simultaneously debit the amount at the checkout, as many cardholders do nowadays. As the app declares that the customer is the authorized user of the credit card, the vendor does not realize that the transaction is fraudulent. The crucial factor is that the app outsmarts the card’s security system. Although the amount is over the limit and requires PIN verification, no code is requested.

The paper: “The EMV Standard: Break, Fix, Verify.”

Abstract: EMV is the international protocol standard for smartcard payment and is used in over 9 billion cards worldwide. Despite the standard’s advertised security, various issues have been previously uncovered, deriving from logical flaws that are hard to spot in EMV’s lengthy and complex specification, running over 2,000 pages.

We formalize a comprehensive symbolic model of EMV in Tamarin, a state-of-the-art protocol verifier. Our model is the first that supports a fine-grained analysis of all relevant security guarantees that EMV is intended to offer. We use our model to automatically identify flaws that lead to two critical attacks: one that defrauds the cardholder and another that defrauds the merchant. First, criminals can use a victim’s Visa contact-less card for high-value purchases, without knowledge of the card’s PIN. We built a proof-of-concept Android application and successfully demonstrated this attack on real-world payment terminals. Second, criminals can trick the terminal into accepting an unauthentic offline transaction, which the issuing bank should later decline, after the criminal has walked away with the goods. This attack is possible for implementations following the standard, although we did not test it on actual terminals for ethical reasons. Finally, we propose and verify improvements to the standard that prevent these attacks, as well as any other attacks that violate the considered security properties.The proposed improvements can be easily implemented in the terminals and do not affect the cards in circulation.

Upcoming Speaking Engagements

[2020.09.14] This is a current list of where and when I am scheduled to speak:

The list is maintained on this page.

Since 1998, CRYPTO-GRAM has been a free monthly newsletter providing summaries, analyses, insights, and commentaries on security technology. To subscribe, or to read back issues, see Crypto-Gram’s web page.

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Bruce Schneier is an internationally renowned security technologist, called a security guru by the Economist. He is the author of over one dozen books — including his latest, Click Here to Kill Everybody — as well as hundreds of articles, essays, and academic papers. His newsletter and blog are read by over 250,000 people. Schneier is a fellow at the Berkman Klein Center for Internet and Society at Harvard University; a Lecturer in Public Policy at the Harvard Kennedy School; a board member of the Electronic Frontier Foundation, AccessNow, and the Tor Project; and an advisory board member of EPIC and

Copyright © 2020 by Bruce Schneier.

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