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Levels of Assurance for DoD Microelectronics

The NSA has has published criteria for evaluating levels of assurance required for DoD microelectronics.

The introductory report in a DoD microelectronics series outlines the process for determining levels of hardware assurance for systems and custom microelectronic components, which include application-specific integrated circuits (ASICs), field programmable gate arrays (FPGAs) and other devices containing reprogrammable digital logic.

The levels of hardware assurance are determined by the national impact caused by failure or subversion of the top-level system and the criticality of the component to that top-level system. The guidance helps programs acquire a better understanding of their system and components so that they can effectively mitigate against threats.

The report was published last month, but I only just noticed it.

Posted on August 29, 2022 at 9:30 AMView Comments

Security and Cheap Complexity

I’ve been saying that complexity is the worst enemy of security for a long time now. (Here’s me in 1999.) And it’s been true for a long time.

In 2018, Thomas Dullien of Google’s Project Zero talked about “cheap complexity.” Andrew Appel summarizes:

The anomaly of cheap complexity. For most of human history, a more complex device was more expensive to build than a simpler device. This is not the case in modern computing. It is often more cost-effective to take a very complicated device, and make it simulate simplicity, than to make a simpler device. This is because of economies of scale: complex general-purpose CPUs are cheap. On the other hand, custom-designed, simpler, application-specific devices, which could in principle be much more secure, are very expensive.

This is driven by two fundamental principles in computing: Universal computation, meaning that any computer can simulate any other; and Moore’s law, predicting that each year the number of transistors on a chip will grow exponentially. ARM Cortex-M0 CPUs cost pennies, though they are more powerful than some supercomputers of the 20th century.

The same is true in the software layers. A (huge and complex) general-purpose operating system is free, but a simpler, custom-designed, perhaps more secure OS would be very expensive to build. Or as Dullien asks, “How did this research code someone wrote in two weeks 20 years ago end up in a billion devices?”

This is correct. Today, it’s easier to build complex systems than it is to build simple ones. As recently as twenty years ago, if you wanted to build a refrigerator you would create custom refrigerator controller hardware and embedded software. Today, you just grab some standard microcontroller off the shelf and write a software application for it. And that microcontroller already comes with an IP stack, a microphone, a video port, Bluetooth, and a whole lot more. And since those features are there, engineers use them.

Posted on August 26, 2022 at 6:54 AMView Comments

Man-in-the-Middle Phishing Attack

Here’s a phishing campaign that uses a man-in-the-middle attack to defeat multi-factor authentication:

Microsoft observed a campaign that inserted an attacker-controlled proxy site between the account users and the work server they attempted to log into. When the user entered a password into the proxy site, the proxy site sent it to the real server and then relayed the real server’s response back to the user. Once the authentication was completed, the threat actor stole the session cookie the legitimate site sent, so the user doesn’t need to be reauthenticated at every new page visited. The campaign began with a phishing email with an HTML attachment leading to the proxy server.

Posted on August 25, 2022 at 6:45 AMView Comments

Mudge Files Whistleblower Complaint against Twitter

Peiter Zatko, aka Mudge, has filed a whistleblower complaint with the SEC against Twitter, claiming that it violated an eleven-year-old FTC settlement by having lousy security. And he should know; he was Twitter’s chief security officer until he was fired in January.

The Washington Post has the scoop (with documents) and companion backgrounder. This CNN story is also comprehensive.

EDITED TO ADD: Another news article. Slashdot thread.

EDITED TO ADD (9/2): More info.

Posted on August 24, 2022 at 6:40 AMView Comments

Signal Phone Numbers Exposed in Twilio Hack

Twilio was hacked earlier this month, and the phone numbers of 1,900 Signal users were exposed:

Here’s what our users need to know:

  • All users can rest assured that their message history, contact lists, profile information, whom they’d blocked, and other personal data remain private and secure and were not affected.
  • For about 1,900 users, an attacker could have attempted to re-register their number to another device or learned that their number was registered to Signal. This attack has since been shut down by Twilio. 1,900 users is a very small percentage of Signal’s total users, meaning that most were not affected.

We are notifying these 1,900 users directly, and prompting them to re-register Signal on their devices.

If you were not notified, don’t worry about it. But it does bring up the old question: Why does Signal require a phone number to use? It doesn’t have to be that way.

Posted on August 23, 2022 at 6:30 AMView Comments

Hyundai Uses Example Keys for Encryption System

This is a dumb crypto mistake I had not previously encountered:

A developer says it was possible to run their own software on the car infotainment hardware after discovering the vehicle’s manufacturer had secured its system using keys that were not only publicly known but had been lifted from programming examples.

[…]

“Turns out the [AES] encryption key in that script is the first AES 128-bit CBC example key listed in the NIST document SP800-38A [PDF]”.

[…]

Luck held out, in a way. “Greenluigi1” found within the firmware image the RSA public key used by the updater, and searched online for a portion of that key. The search results pointed to a common public key that shows up in online tutorials like “RSA Encryption & Decryption Example with OpenSSL in C.

EDITED TO ADD (8/23): Slashdot post.

Posted on August 22, 2022 at 6:38 AMView Comments

Friday Squid Blogging: The Language of the Jumbo Flying Squid

The jumbo flying squid (Dosidicus gigas) uses its color-changing ability as a language:

In 2020, however, marine biologists discovered that jumbo flying squid are surprisingly coordinated. Despite their large numbers, the squid rarely bumped into each other or competed for the same prey. The scientists hypothesized that the flickering pigments allowed the squid to quickly communicate complex messages, such as when it was preparing to attack and what it was targeting.

The researchers observed that the squid displayed 12 distinct pigmentation patterns in a variety of sequences, similar to how humans arrange words in a sentence. For example, squid darkened while pursuing prey and then shifted to a half light/half dark pattern immediately before striking. The researchers hypothesized that these whole-body pigment changes signaled a precise action, such as “I’m about to attack.”

More interestingly (or worrisome), the researchers also believe the squid use subtle pigment changes to provide more context to the action. For example, they sometimes flashed pale stripes along their torso before darkening, possibly denoting the type or location of prey. This suggested that the squid may arrange the patterns to modify the meaning of other patterns, creating what humans call “syntax.”

As usual, you can also use this squid post to talk about the security stories in the news that I haven’t covered.

Read my blog posting guidelines here.

Posted on August 19, 2022 at 4:05 PMView Comments

USB “Rubber Ducky” Attack Tool

The USB Rubber Ducky is getting better and better.

Already, previous versions of the Rubber Ducky could carry out attacks like creating a fake Windows pop-up box to harvest a user’s login credentials or causing Chrome to send all saved passwords to an attacker’s webserver. But these attacks had to be carefully crafted for specific operating systems and software versions and lacked the flexibility to work across platforms.

The newest Rubber Ducky aims to overcome these limitations. It ships with a major upgrade to the DuckyScript programming language, which is used to create the commands that the Rubber Ducky will enter into a target machine. While previous versions were mostly limited to writing keystroke sequences, DuckyScript 3.0 is a feature-rich language, letting users write functions, store variables, and use logic flow controls (i.e., if this… then that).

That means, for example, the new Ducky can run a test to see if it’s plugged into a Windows or Mac machine and conditionally execute code appropriate to each one or disable itself if it has been connected to the wrong target. It also can generate pseudorandom numbers and use them to add variable delay between keystrokes for a more human effect.

Perhaps most impressively, it can steal data from a target machine by encoding it in binary format and transmitting it through the signals meant to tell a keyboard when the CapsLock or NumLock LEDs should light up. With this method, an attacker could plug it in for a few seconds, tell someone, “Sorry, I guess that USB drive is broken,” and take it back with all their passwords saved.

Posted on August 18, 2022 at 6:45 AMView Comments

Zoom Exploit on MacOS

This vulnerability was reported to Zoom last December:

The exploit works by targeting the installer for the Zoom application, which needs to run with special user permissions in order to install or remove the main Zoom application from a computer. Though the installer requires a user to enter their password on first adding the application to the system, Wardle found that an auto-update function then continually ran in the background with superuser privileges.

When Zoom issued an update, the updater function would install the new package after checking that it had been cryptographically signed by Zoom. But a bug in how the checking method was implemented meant that giving the updater any file with the same name as Zoom’s signing certificate would be enough to pass the test—so an attacker could substitute any kind of malware program and have it be run by the updater with elevated privilege.

It seems that it’s not entirely fixed:

Following responsible disclosure protocols, Wardle informed Zoom about the vulnerability in December of last year. To his frustration, he says an initial fix from Zoom contained another bug that meant the vulnerability was still exploitable in a slightly more roundabout way, so he disclosed this second bug to Zoom and waited eight months before publishing the research.

EDITED TO ADD: Disclosure works. The vulnerability seems to be patched now.

Posted on August 17, 2022 at 6:11 AMView Comments

Sidebar photo of Bruce Schneier by Joe MacInnis.