This Week In Security: No More CVEs, 4chan, And Recall Returns

The sky is falling. Or more specifically, it was about to fall, according to the security community this week. The MITRE Corporation came within a hair’s breadth of running out of its contract to maintain the CVE database. And admittedly, it would be a bad thing if we suddenly lost updates to the central CVE database. What’s particularly interesting is how we knew about this possibility at all. An April 15 letter sent to the CVE board warned that the specific contract that funds MITRE’s CVE and CWE work was due to expire on the 16th. This was not an official release, and it’s not clear exactly how this document was leaked.

Many people made political hay out of the apparent imminent carnage. And while there’s always an element of political maneuvering when it comes to contract renewal, it’s worth noting that it’s not unheard of for MITRE’s CVE funding to go down to the wire like this. We don’t know how many times we’ve been in this position in years past. Regardless, MITRE has spun out another non-profit, The CVE Foundation, specifically to see to the continuation of the CVE database. And at the last possible moment, CISA has announced that it has invoked an option in the existing contract, funding MITRE’s CVE work for another 11 months.

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An electron microscope image of the aluminum alloy from the study.

D20-shaped Quasicrystal Makes High-Strength Alloy Printable

When is a crystal not a crystal? When it’s a quasi-crystal, a paradoxical form of metal recently found in some 3D printed metal alloys by [A.D. Iams et al] at the American National Institute for Standards and Technology (NIST).

As you might remember from chemistry class, crystals are made up of blocks of atoms (usually called ‘unit cells’) that fit together in perfect repetition — baring dislocations, cracks, impurities, or anything else that might throw off a theoretically perfect crystal structure. There are only so many ways to tessellate atoms in 3D space; 230 of them, to be precise. A quasicrystal isn’t any of them. Rather than repeat endlessly in 3D space, a quasicrystal never repeats perfectly, like a 3D dimensional Penrose tile. The discovery of quasicrystals dates back to the 1980s, and was awarded a noble prize in 2011.

Penrose tiling of thick and thin rhombi
Penrose tiling– the pattern never repeats perfectly. Quasicrystals do this in 3D. (Image by Inductiveload, Public Domain)

Quasicrystals aren’t exactly common in nature, so how does 3D printing come into this? Well, it turns out that, quite accidentally, a particular Aluminum-Zirconium alloy was forming small zones of quasicrystals (the black spots in the image above) when used in powder bed fusion printing. Other high strength-alloys tended to be very prone to cracking, to the point of unusability, and this Al-Zr alloy, discovered in 2017, was the first of its class.

You might imagine that the non-regular structure of a quasicrystal wouldn’t propagate cracks as easily as a regular crystal structure, and you would be right! The NIST researchers obviously wanted to investigate why the printable alloy had the properties it does. When their crystallographic analysis showed not only five-fold, but also three-fold and two-fold rotational symmetry when examined from different angles, the researchers realized they had a quasicrystal on their hands. The unit cell is in the form of a 20-sided icosahedron, providing the penrose-style tiling that keeps the alloy from cracking.

You might say the original team that developed the alloy rolled a nat-20 on their crafting skill. Now that we understand why it works, this research opens up the doors for other metallic quasi-crystals to be developed on purpose, in aluminum and perhaps other alloys.

We’ve written about 3D metal printers before, and highlighted a DIY-able plastic SLS kit, but the high-power powder-bed systems needed for aluminum aren’t often found in makerspaces. If you’re building one or know someone who is, be sure to let us know.

Track Your Circuits: A Locomotive PCB Badge

This fun PCB from [Nick Brown] features a miniature railroad implemented with 0805-sized LEDs. With an eye towards designing his own fun interactive PCB badge, the Light-Rail began its journey. He thoroughly documented his process, from shunting various late-night ideas together to tracking down discrepancies between the documentation of a part and the received part.

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