DIY Test Gear from 1981

We can’t get enough of [Bettina Neumryn’s] videos. If you haven’t seen her, she takes old electronics magazines, finds interesting projects, and builds them. If you remember these old projects, it is nostalgic, and if you don’t remember them, you can learn a lot about basic electronics and construction techniques. This installment (see below) is an Elektor digital voltmeter and frequency counter from late 1981.

As was common in those days, you could find the PCB layouts in the magazine. In this case, there were two boards. The schematic shows that a counter and display driver chip — a 74C928 — does most of the heavy lifting for the display and the counter.

It is easy to understand how the frequency counter works. You clip the input with a pair of diodes, amplify it a bit, square it with a Schmitt trigger, and then, possibly, prescale it using a divider. The voltmeter is a little trickier: it uses a voltage divider, an op amp, and a 555 to convert the voltage to a frequency.

Of course, finding the parts for an old project can be a challenge. A well-stocked junk drawer doesn’t hurt. A PCB etching setup helps, too.

We’ve looked at her magazine rebuilds before. If you ever get the urge to tackle a project like this, you can find all the grand old magazines online.

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Build A High Voltage Supply For Vacuum Tube Work

If you work on simple digital projects, just about any bench supply will offer the voltage and current you’re looking for. However, if you’re working with valves, you’ll often find yourself needing much higher voltages that can be tricky to source. [Chappy Happy] has shared a design for a simple HV power supply that should prove useful to vacuum tube enthusiasts.

The build is fairly basic in nature, lacing together some commonly available parts to generate the necessary voltages for working with common vacuum tubes from a 12 volt DC input. Inside the supply is a UC3843A DC boost converter, set up to output high voltage up to around 300 volts DC, with a ripple filter added for good measure. The output can be adjusted with a knob, with a voltmeter on the front panel. There’s also a 12-volt output, and a LM2596 step down converter to produce 6.3 volts for the filament supply. The whole project is built in an old Heathkit project box, and he demonstrates the supply with a simple single-tube amplifier.

If you find yourself regularly whipping up tube circuits, you might like to have something like this on your workbench. Or, you might even consider cooking up your own tubes from scratch if you’re more adventurous like that. Video after the break.

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[Thanks to Stephen Walters for the tip!]

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The Zen Must Flow From Arrakis Sand Table

In Dune, the Fremen people of Arrakis practice an odd future hybrid religion called “zensunni.” This adds an extra layer of meaning to the title of [Mark Rehorst]’s Arrakis 3.0 sand table, given that the inspiration for the robotic sand table seems to be Zen gardens from Japan.

The dunes on the tabletop version of Arrakis owe nothing to sand worms, but are instead created a rolling metal ball. With all workings happening below, it looks quite magical to the uninitiated, but of course it’s not magic: it’s magnets. Just beneath the tabletop and its sands, the steel ball is being dragged along by the magnetic field of a powerful neodynium magnet.

That magnet is mounted in a CoreXY motion system that owes more than a little bit to modern 3D printers. Aside from the geometry, it’s using the standard G6 belt we see so often, along with a Duet3D mainboard, NEMA 17 steppers, and many 3D printed parts to hold its aluminum extrusions together. Thanks to that printer-inspired motion system, the ball can whirl around at 2000 mm/s, though [Mark] prefers to run slower: the demo video below shows operation at 1000 mm/s before the sand has been added.

This build was designed for ease of construction and movement: sized at 2’x4′ (about 61 cm x 122 cm), it fits through doors and fits an off-the-shelf slab of coffee table glass, something that [Mark] wishes he’d considered when building version two. That’s the nice thing about jumping in on a project someone’s been iterating for a while: you’ve got the benefit of learning from their mistakes. You can see the roots of this design, and what has changed, from the one he showed us in 2020.

Naturally you’re not limited to CoreXY for a sand table, though it is increasingly popular — we’ve seen examples with polar mechanisms and even a SCARA arm.

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La compravendita degli accessi ai firewall FortiGate italiani nel Dark Web

Negli ultimi giorni, su un forum underground noto per ospitare attività illegali, è apparso un annuncio che merita molta attenzione.

Un utente appena registrato, con il nickname “Sarcoma”, ha pubblicato un messaggio in cui si dice disposto ad acquistare accessi ai pannelli di amministrazione dei firewall FortiGate.

L’annuncio è piuttosto esplicito: offre un compenso a partire da 20 dollari ad accesso e specifica che gli interessano accessi provenienti da Stati Uniti, Canada, Italia e Germania. Per rendere il tutto più credibile ha allegato anche uno screenshot che richiama l’interfaccia di gestione dei sistemi Fortinet.
Post pubblicato da un threat actors su un forum underground del dark web

La Compravendita sul DarkWeb

Il valore di un pannello amministrativo FortiGate nelle mani sbagliate è enorme. Chi riesce ad entrarci può alterare completamente il comportamento del firewall: aprire porte, creare backdoor, disattivare i log e preparare il terreno per intrusioni più profonde. Non è un caso che questi accessi siano molto ricercati nel cybercrime.

Questi forum non sono semplici bacheche: sono veri e propri mercati neri in cui si incontrano due figure chiave. Da una parte ci sono gli Initial Access Broker (IaB), professionisti del crimine informatico che si specializzano nell’individuare vulnerabilità, configurazioni sbagliate o credenziali esposte. Il loro compito è ottenere un primo punto di ingresso nelle reti aziendali. Dall’altra parte ci sono gruppi criminali più strutturati, spesso legati ad attività di ransomware o furto di dati, che acquistano questi accessi pronti all’uso per muoversi più velocemente e ridurre i costi delle intrusioni. È un ecosistema perfettamente organizzato, in cui ognuno trae profitto da una parte specifica della “filiera”.
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Cosa occorre fare

La presenza di un annuncio rivolto anche alla geografia italiana è un segnale chiaro: le aziende del nostro Paese restano un bersaglio appetibile, soprattutto quando i loro firewall non vengono aggiornati o vengono lasciati esposti su Internet senza le dovute precauzioni. Per difendersi è fondamentale applicare con regolarità tutte le patch di sicurezza rilasciate da Fortinet, molte delle quali riguardano vulnerabilità critiche che in passato sono state sfruttate proprio per ottenere accesso non autorizzato ai sistemi.

Un altro aspetto troppo spesso sottovalutato riguarda la visibilità dei servizi di amministrazione. I pannelli di gestione e gli strumenti utilizzati per configurare i firewall non dovrebbero essere mai raggiungibili direttamente dalla rete pubblica.
Un altro forum underground in lingua russa dove un criminale informatico riporta accessi ad una azienda italiana che utilizza un FortiGate
È necessario isolarli, limitarne drasticamente l’accesso e renderli disponibili solo attraverso reti interne, VPN sicure e metodi di autenticazione più robusti. Lasciarli esposti equivale a offrire un bersaglio perfetto, pronto per essere scambiato nei forum underground proprio come l’annuncio che ha dato il via a questa riflessione.

In un contesto in cui gli accessi si comprano e vendono come una qualsiasi merce digitale, la sicurezza delle reti aziendali non può più permettersi leggerezze. Ogni sistema esposto è una potenziale porta d’ingresso, e qualcuno là fuori è pronto a pagarla – anche pochi dollari – pur di aprirla.

Questo articolo si basa su informazioni, integralmente o parzialmente tratte dalla piattaforma di intelligence di Recorded Future, partner strategico di Red Hot Cyber e punto di riferimento globale nell’intelligence sulle minacce informatiche. La piattaforma fornisce analisi avanzate utili a individuare e contrastare attività malevole nel cyberspazio.

L'articolo La compravendita degli accessi ai firewall FortiGate italiani nel Dark Web proviene da Red Hot Cyber.

Citizen Science by the Skin of Your Teeth

If you are a schoolkid of the right age, you can’t wait to lose a baby tooth. In many cultures, there is a ritual surrounding it, like the tooth fairy, a mouse who trades your tooth for a gift, or burying the tooth somewhere significant. But in 1958, a husband and wife team of physicians wanted children’s teeth for a far different purpose: quantifying the effects of nuclear weapons testing on the human body.
A young citizen scientist (State Historical Society of Missouri)
Louise and Eric Reiss, along with some other scientists, worked with Saint Louis University and the Washington School of Dental Medicine to collect and study children’s discarded teeth. They were looking for strontium-90, a nasty byproduct of above-ground nuclear testing. Strontium is similar enough to calcium that consuming it in water and dairy products will leave the material in your bones, including your teeth.

The study took place in the St. Louis area, and the results helped convince John F. Kennedy to sign the Partial Nuclear Test Ban Treaty.

They hoped to gather 50,000 teeth in a year. By 1970, 12 years later, they had picked up over 320,000 donated teeth. While a few kids might have been driven by scientific altruism, it didn’t hurt that the program used colorful posters and promised each child a button to mark their participation.

Children’s teeth were particularly advantageous to use because they are growing and are known to readily absorb radioactive material, which can cause bone tumors.

Scale

A fair trade for an old tooth? (National Museum of American History)
You might wonder just how much nuclear material is floating around due to bombs. Obviously, there were two bombs set off during the war, as well as the test bombs required to get to that point. Between 1945 and 1980, there were five countries conducting atmospheric tests at thirteen sites. The US, accounting for about 65% of the tests, the USSR, the UK, France, and China detonated 504 nuclear devices equivalent to about 440 megatons of TNT.

Well over 500 bombs with incredible force have put a lot of radioactive material into the atmosphere. That doesn’t count, too, the underground tests that were not always completely contained. For example, there were two detonations in Mississippi where the radiation was contained until they drilled holes for instruments, leaving contaminated soil on the surface. Today, sites like this have “monuments” explaining that you shouldn’t dig in the area.

Of course, above-ground tests are worse, with fallout affecting “downwinders” or people who live downwind of the test site. There have been more than one case of people, unaware of the test, thinking the fallout particles were “hot snow” and playing in it. Test explosions have sent radioactive material into the stratosphere. This isn’t just a problem for people living near the test sites.

Results

By 1961, the team published results showing that strontium-90 levels in the teeth increased depending on when the child was born. Children born in 1963 had levels of strontium-90 fifty times higher than those born in 1950, when there was very little nuclear testing.

The results were part of the reason that President Kennedy agreed to an international partial test ban, as you can see in the Lincoln Presidential Foundation video below. You may find it amazing that people would plan trips to watch tests, and they were even televised.

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In 2001, Washington University found 85,000 of the teeth stored away. This allowed the Radiation and Public Health Project to track 3,000 children who were, by now, adults, of course.

Sadly, 12 children who had died from cancer before age 50 had baby teeth with twice the levels of the teeth of people who were still alive at age 50. To be fair, the Nuclear Regulatory Commission has questioned these findings, saying the study is flawed and fails to account for other risk factors.

And teeth don’t just store strontium. In the 1970s, other researchers used baby teeth to track lead ingestion levels. Baby teeth have also played a role in the Flint Water scandal. In South Africa, the Tooth Fairy Project monitored heavy metal pollution in children’s teeth, too.

Teeth aren’t the only indicator of nuclear contamination. Steel is also at risk.

Featured image: “Castle Bravo Blast” by United States Department of Energy.

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