Selecting a random sample from a set is simple. But what about selecting a fair random sample from a set of unknown or indeterminate size? That’s where reservoir sampling comes in, and [Sam Rose] has a beautifully-illustrated, interactive guide to how reservoir sampling works. As far as methods go, it’s as elegant as it is simple, and particularly suited to fairly sampling dynamic datasets like sipping from a firehose of log events.

While reservoir sampling is simple in principle it’s not entirely intuitive to everyone. That’s what makes [Sam]’s interactive essay so helpful; he first articulates the problem before presenting the solution in a way that makes it almost self-evident.

[Sam] uses an imaginary deck of cards to illustrate the problem. If one is being dealt cards one at a time from a deck of unknown size (there could be ten cards, or a million), how can one choose a single card in a way that gives each an equal chance of having been selected? Without collecting them all first?

In a nutshell, the solution is to make a decision every time a new card arrives: hold onto the current card, or replace it with the new one. Each new card is given a 1/n chance of becoming held, where n is the number of cards we’ve seen so far. That’s all it takes. No matter when the dealer stops dealing, each card that has been seen will have had an equal chance of ending up the one selected.

There are a few variations which [Sam] also covers, and practical ways of applying it to log collection, so check it out for yourself.

If [Sam]’s knack for illustrating concepts in an interactive way is your jam, we have one more to point out. Our own Al Williams wrote a piece on Turing machines; the original “universal machine” being a theoretical device with a read/write head and infinite paper tape. A wonderful companion to that article is [Sam]’s piece illustrating exactly how such a Turing machines would work in an interactive way.

hackaday.com/2025/07/02/reserv…

How many times do you have to forget your keys before you start hacking on the problem? For [Binh], the answer was 5 in the last month, and his hack was to make a gesture-based door unlocker. Which leads to the amusing image of [Binh] in a hallway throwing gang signs until he is let in.

The system itself is fairly simple in its execution: the existing deadbolt is actuated by a NEMA 17 stepper turning a 3D printed bevel gear. It runs 50 steps to lock or unlock, apparently, then the motor turns off, so it’s power-efficient and won’t burn down [Binh]’s room.

The software is equally simple; mediapipe is an ML library that can already do finger detection and be accessed via Python. Apparently gesture recognition is fairly unreliable, so [Binh] just has it counting the number of fingers flashed right now. In this case, it’s running on a Rasberry Pi 5 with a webcam for image input. The Pi connects via USB serial to an ESP32 that is connected to the stepper driver. [Binh] had another project ready to be taken apart that had the ESP32/stepper combo ready to go so this was the quickest option. As was mounting everything with double-sided tape, but that also plays into a design constraint: it’s not [Binh]’s door.

[Binh] is staying in a Hacker Hotel, and as you might imagine, there’s been more penetration testing on this than you might get elsewhere. It turns out it’s relatively straightforward to brute force (as you might expect, given it is only counting fingers), so [Binh] is planning on implementing some kind of 2FA. Perhaps a secret knock? Of course he could use his phone, but what’s the fun in that?

Whatever the second factor is, hopefully it’s something that cannot be forgotten in the room. If this project tickles your fancy, it’s open source on GitHub, and you can check it out in action and the build process in the video embedded below.

After offering thanks to [Binh] for the tip, the remaining words of this article will be spent requesting that you, the brilliant and learned hackaday audience, provide us with additional tips.

youtube.com/embed/yNJkpo-19DI?…

hackaday.com/2025/07/02/hack-s…

FOR IMMEDIATE RELEASE:

Paramount Global, which owns CBS News, has reportedly decided to settle President Donald Trump’s frivolous lawsuit over the editing of a “60 Minutes” interview with his former presidential rival Kamala Harris.

Virtually no one aside from Trump’s hangers-on believes the case had any merit, let alone $16 million worth. There was no rational reason for Paramount to settle — aside from paying for favoritism, including over its planned merger with Skydance Media.

Legendary First Amendment lawyers Floyd Abrams and James Goodale each recall a time when news outlets were owned by news companies that had both economic and principled interests in defending the First Amendment. They’re alarmed by what they’re seeing today.

“The agreement of Paramount to pay any settlement amount to Donald Trump ... is an ominous blow to press freedom in our nation.”

Floyd Abrams

Abrams, who represented The New York Times during the Pentagon Papers case and had a hand in countless other seminal First Amendment rulings, told Freedom of the Press Foundation (FPF) via email that “the agreement of Paramount to pay any settlement amount to Donald Trump based on a ‘60 Minutes’ broadcast that was both journalistically responsible and fully protected by the First Amendment is an ominous blow to press freedom in our nation.”

As Abrams noted in a letter to the Times, despite the significant challenges the Trump administration presents for media outlets, “it is not too much for the public to ask of the press that it remain vigilant in its coverage of him and militant in defense of itself.”

Goodale, the Times vice president, vice chairman, and general counsel from 1963 to 1980, led the newspaper’s resistance to the Nixon administration’s war on the press. He told FPF in an email, “It’s a sad day for journalism in the United States when the corporate owners of major news broadcasters are unwilling to fight back against baseless lawsuits by politicians.”

“It’s a sad day for journalism in the United States when the corporate owners of major news broadcasters are unwilling to fight back against baseless lawsuits by politicians.”

James Goodale

Goodale reiterated his view, which he also expressed in a prior interview with FPF, that businesspeople unwilling to safeguard reporters’ rights should choose a different industry. “Operating a news outlet is a serious responsibility and those whose other financial interests won’t allow them to stand up for the First Amendment should stay out of the news business.”

Seth Stern, FPF’s director of advocacy, added that Paramount’s settlement and other capitulations by major media outlets “put to rest the myth that billionaires and corporate conglomerates will refrain from meddling with the editorial affairs of news publishers they own. CBS and other corporate-owned news outlets are full of great journalists who deserve ownership that won’t throw them under the bus to make a buck. Americans concerned by these developments should support independent news outlets willing to stand up for their journalists’ First Amendment rights so that our free press can survive this administration.”

Please contact us if you would like further comment.

freedom.press/issues/legendary…

When it comes to text, how small is too small? The experts say a six point font is the minimum for readability, but as [James Bowman] shows us, you can get away with half of that.

The goal is to produce a 40-character display on a 24 mm x 24 mm LCD that has a resolution of 240 x 240 to show a serial terminal (or other data) on the “TermDriver2” USB-to-Serial adapter. With 24 lines, that’s a line per millimeter: very small text. Three points, to be precise, half what the experts say you need. Diving this up into 40 columns gives a character cell of six by nine pixels. Is it enough?

The raw font on the left, the subpixel rendering on the right. For once, it’s better if you don’t click to enlarge.
Not by itself, no. That’s where the hack comes in: sub-pixel rendering. After all, a “white” pixel on an LCD is actually three elements: a red, a green, and a blue subpixel, stacked side-by-each. Drive each of those subpixels independently and 240 pixels now becomes 720. That’s plenty for a 40 column terminal.

The article discusses how, in general terms, they pulled off the subpixel rendering and kept the font as legible as possible. We think it’s a good try, though the colored fringe around the characters can be uncomfortable to look at for some people — and then we can’t forget the physical size of the characters being 1 mm tall.

If this trick were being used on a larger display with a 240-wide resolution, we’d say “yes, very legible, good job!”– but at this size? We hope we can find our reading glasses. Still, it’s a neat trick to have in your back pocket for driving low-resolution LCDs.

It may not surprise you that aside from improving legibility, subpixel rendering is also used for pixel (er, sub-pixel) art.

The full set of glyphs in their subpixel-rendered glory.

hackaday.com/2025/07/02/subpix…

FOR IMMEDIATE RELEASE:

Paramount Global announced late Tuesday that it will pay $16 million to settle an entirely frivolous and unconstitutional lawsuit brought by President Donald Trump over the editing of a “60 Minutes” interview with Kamala Harris.

It’s been widely reported that the settlement is intended to clear the way for federal approval of the sale of Paramount to Skydance Media, which will result in a multimillion-dollar payout to Paramount Chair Shari Redstone.

Three U.S. senators previously launched an investigation into whether paying off Trump through a settlement to obtain approval of the sale would violate federal bribery and other laws, and the California Senate opened a similar investigation.

The following statement can be attributed to Seth Stern, director of advocacy at Freedom of the Press Foundation (FPF):

Today is a dark day for press freedom. Paramount’s spineless decision to settle Trump’s baseless and patently unconstitutional lawsuit is an insult to the journalists of ‘60 Minutes’ and an invitation to Trump to continue targeting other news outlets. Each time a company cowers and surrenders to Trump’s demands it only emboldens him to do it again.

It will be remembered as one of the most shameful capitulations by the press to a president in history.

But we are not done fighting. We’ve already filed a shareholder information demand and are sending a second demand today to uncover information about this decision. With that information, we will continue to pursue our legal options to stop this affront to Paramount shareholders, CBS journalists, and the First Amendment. Paramount directors should be held accountable and we will do all we can to make that happen.

FPF is a Paramount Global shareholder, and you can read our letter notifying Paramount of our plans to take legal action in the event of a settlement with Trump here. You can read a previous statement from our counsel here, and our recent demand for information to which we are entitled as shareholders here.

Please contact us if you would like further comment.

freedom.press/issues/paramount…

This week Jonathan chats with benny Vasquez about AlmaLinux! Why is AlmaLinux the choice for slightly older hardware? What is the deal with RISC-V? And how does EPEL fit in? Tune in to find out!

• linkedin.com/in/bennyvasquez/
• almalinux.org
• almalinux.org/blog/2025-04-24-…
• almalinux.org/blog/2025-06-26-…

youtube.com/embed/5G-wIcFLrnM?…

Did you know you can watch the live recording of the show right on our YouTube Channel? Have someone you’d like us to interview? Let us know, or contact the guest and have them contact us! Take a look at the schedule here.

play.libsyn.com/embed/episode/…

Direct Download in DRM-free MP3.

If you’d rather read along, here’s the transcript for this week’s episode.

Places to follow the FLOSS Weekly Podcast:

• Spotify
• RSS

Theme music: “Newer Wave” Kevin MacLeod (incompetech.com)

Licensed under Creative Commons: By Attribution 4.0 License

hackaday.com/2025/07/02/floss-…

Le autorità spagnole hanno arrestato cinque persone sospettate di aver riciclato 540 milioni di dollari tramite investimenti illegali in criptovalute e di aver frodato più di 5.000 persone. L’operazione di polizia, denominata Borrelli, è stata condotta con il supporto e il coordinamento dell’Europol, nonché delle forze dell’ordine di Estonia, Francia e Stati Uniti.

Le truffe sugli investimenti in criptovalute vengono solitamente messe in atto tramite la truffa romantica (conosciuta anche come macellazione del maiale), divenuta popolare negli ultimi anni.

Lo schema prevede che i truffatori utilizzino l’ingegneria sociale e contattino persone (“maiali”) sui social media e sulle app di incontri. Col tempo, i criminali si guadagnano la fiducia delle vittime simulando un’amicizia o un interesse romantico, e a volte persino fingendosi amici nella vita reale delle vittime.

Una volta stabilito il “contatto”, a un certo punto i criminali propongono alla vittima di investire in criptovalute, reindirizzando la vittima a un sito web fasullo. Purtroppo, di solito è impossibile recuperare i fondi e ricevere il reddito dichiarato da tali “investimenti“. Di norma, dopo l'”investimento“, i fondi vengono movimentati attraverso numerosi conti, il che li rende estremamente difficili da tracciare.

L’indagine sulle attività del gruppo fraudolento è iniziata nel 2023. Da allora, gli esperti di reati finanziari di Europol hanno assistito le autorità spagnole coordinando le indagini e fornendo supporto operativo. Il giorno dell’operazione, un esperto di criptovalute è stato persino inviato in Spagna per assistere gli investigatori.

Mentre i metodi utilizzati dai criminali sono ancora oggetto di indagine, la polizia afferma di aver ormai compreso il modus operandi del gruppo, che ha spostato e nascosto i fondi rubati attraverso i suoi canali in Asia.

“Per svolgere le loro attività fraudolente, si ritiene che i leader del gruppo criminale si siano avvalsi di una rete di complici in tutto il mondo che raccoglievano fondi tramite prelievi di contanti, bonifici bancari e trasferimenti di criptovalute”, ha dichiarato Europol. “Gli investigatori sospettano che l’organizzazione criminale abbia creato una rete aziendale e bancaria con sede a Hong Kong che utilizzava gateway di pagamento e conti su vari exchange, creati a nome di persone diverse, per ricevere, conservare e trasferire fondi ottenuti tramite attività criminali”.

La dichiarazione di Europol sottolinea specificamente il ruolo dell’intelligenza artificiale nella diffusione delle frodi sugli investimenti, che stanno diventando sempre più sofisticate.

L'articolo Pig Butchering Scam: Arrestati 5 criminali in Spagna per una frode da 540 milioni di dollari proviene da il blog della sicurezza informatica.

When a fire breaks out in a high-rise building, conventional wisdom is that stairwells are the only way out. Lifts are verboten in such scenarios, while sheer height typically prevents any other viable route of egress from tall modern buildings. If the stairs are impassable, or you can’t reach them, you’re in dire peril.

In South Korea, though, there’s another option for escape. The answer involves strapping on a harness and descending down ropes hanging off the side of the building, just like in an action movie. It might sound terrifying, but these descending lifeline devices have become a common part of fire safety infrastructure across the country.

Going Down

The concept is elegantly simple—tall buildings like apartments and hotels feature compact rope escape devices that can be quickly deployed from windows or balconies. These allow people to control their descent down the exterior of a building in the event that there is no other route of escape. While fleeing a building down a rope is typically the preserve of fictional spies or trained climbers, these carefully engineered systems are designed for use by ordinary people in emergency situations.

youtube.com/embed/tboKzq3lx8M?…

The typical Korean descending lifeline comes as a kit with some simple components. It consists of a rope or cable, a friction-based descent control mechanism, and a harness system that can be donned quickly by sliding under the arms and tightening a strap. Deploying the device is relatively simple. The rope reel is attached to a large deployable hook that is firmly mounted to the building’s wall, using a screw-threaded coupling. The rope is then thrown out the window. At this point, the user merely needs to attach the harness and tighten it prior to leaving the building.
A typical lifeline descent kit, manufactured by Kfire. Credit: Kfire
When exiting the window, the user is instructed to face the wall on the way down, using their hands and/or feet to control the descent. Ultimately, though, the mechanical speed regulator ensures a safe pace of descent. The devices only allow the descent of one person at at time. However, each end of the rope has a harness. Thus, when one user has descended to ground level, the next person can grab the harness at the other end which has ascended to the window, and begin their descent. This can continue for as many people as needed.

Key to these devices is their focus on simplicity. The descent control mechanism uses a geared braking system that automatically limit the speed of descent to 1.5 meters/sec or less, preventing the user from descending too quickly even if they panic and release their grip. The lifelines are also sold in a range of different lengths to suit the heights of individual floors in a building. This is important to ensure that as the user hits the ground, the other end of the rope has carried the other harness back up to the floor for the next user. The longest variants typically sold are 45 meters in length, intended for buildings up to 15 stories tall. Limits of practicality mean that while these lifelines are useful for many buildings, they’re perhaps not applicable to taller skyscrapers where such escape would be more difficult.

The engineering challenge here isn’t just mechanical. Automatic rope descent systems are a well understood technology, as are hooks and brackets rated to carry human weight for climbing or otherwise. The real challenge comes down to human factors—in that these systems need to be something people can figure out how to use under conditions of extreme stress. The devices need to be intuitive enough that someone who has never used one before can figure it out while a fire rages behind them. It’s one thing to learn how to use a rope descent system by watching a video and trying the equipment at a calm training session. It’s another thing entirely to do so while a fire rages in the hotel hallway behind you.

While these lifeline systems are relatively simple, they’re still a lot more complicated to use than something like an airliner life jacket. Requiring an inexperienced end user to thread a fitting on a rope coupler without dropping it out the window in a panic situation is a tall ask. Still, the lifelines provide a useful additional escape option. It may not be the easiest way out of the building, or anybody’s first choice, but when there’s no other option, it’s good to have.

South Korea’s adoption of these systems reflects both the country’s high-rise-heavy urban landscape and a pragmatic approach to disaster preparedness. Many apartment buildings and hotels are now required to have these devices installed. The devices are typically mounted in weatherproof boxes near windows or on balconies, ready for deployment when traditional escape routes are compromised. In some cases, the rugged boxes the lifelines come in can even be used as a step-up to ease egress out of higher windows.

Perhaps most importantly, these systems represent a shift in traditional thinking about fire safety. In most jurisdictions, the idea of asking average people to belay down a building is considered untenable—too dangerous and too complicated. In South Korea, the lifelines are on hand, and put control back in the hands of building occupants. When every second counts and traditional escape routes have failed, having a lifeline system could mean the difference between life and death. It’s a sobering reminder that sometimes the best high-tech solution is one that lets people save themselves.

Interested in what Immigration and Customs Enforcement is up to? Step right up to read ICE’s many press releases touting their accomplishments, watch Dr. Phil’s ICE ride-alongs on his new TV network, and, of course, follow ICE on social platform X.

Just don’t expect to read independent reporting about ICE activity — at least not if government officials get their way. Journalists and members of the public who report on ICE are increasingly under attack by officials who would prefer to silence them so government propaganda can fill the information void.

Threatening investigations on spurious grounds

The most recent example is the government’s attack on CNN for its reporting about an app called ICEBlock that alerts users to sightings of ICE agents nearby.

“Border czar” Tom Homan called on the Department of Justice to investigate CNN for its reporting, and Department of Homeland Security Secretary Kristi Noem said her agency is working with the DOJ on a potential prosecution of CNN for “encouraging people to avoid law enforcement activities and operations.”

Press secretary Karoline Leavitt also accused CNN of inciting violence against ICE officers, despite no evidence that ICEBlock, let alone CNN’s reporting on it, has caused any violence.

An app that reports on the presence of law enforcement officers in public isn’t illegal. ICEBlock’s creator told CNN that its purpose is to help people “avoid interactions with ICE,” and many people have legitimate reasons to want to avoid ICE, even if they’re not in the country illegally. At the risk of stating the obvious, journalism about ICEBlock is also legal and protected by the First Amendment.

But none of that has stopped administration officials from making threats, probably with the hope of intimidating CNN and others from reporting on public efforts to counter ICE. They had to have known that their baseless accusations would lead to even more people finding out about ICEBlock. But this isn’t about ICEBlock, it’s about chilling journalism.

Opening baseless investigations

And officials haven’t stopped at just threatening investigations for reporting on ICE. In February, the Federal Communications Commission actually opened an investigation into a California radio station, KCBS, after it reported on ICE raids happening in San Jose.

FCC Chair Brendan Carr said that broadcasting the locations of ICE agents violates FCC rules requiring licensees to operate in the “public interest,” even though such reporting is constitutionally protected. The fact that KCBS is owned by a nonprofit controlled by Democratic megadonor George Soros surely didn’t endear the station to Carr either.

Again, the clear intent of this investigation — and others by the FCC — is to chill news outlets from reporting on ICE and other topics the administration would prefer they avoid. KCBS, for instance, apparently removed the news report on the San Jose raids from its website after the FCC announced its investigation.

Transforming ICE into secret police

Some Republicans in Congress seem to also want in on the secrecy, by turning ICE into the secret police.

In June, Sen. Marsha Blackburn introduced the “Protecting Law Enforcement from Doxxing Act,” a bill that would make it a crime to name a federal law enforcement officer, including ICE officers, in certain circumstances. Sen. Lindsey Graham joined as a co-sponsor of the bill after grandstanding on social media about the need for legislation to prohibit the disclosure of the identities of ICE agents and other federal law enforcement officers.

While Blackburn’s bill requires the “intent to obstruct a criminal investigation or immigration enforcement operation” when naming an ICE officer, that will likely offer little protection when officials are constantly claiming that any public scrutiny of ICE obstructs its work. Those found guilty under the law could be imprisoned for five years.

ICE freezing out transparency

Finally, ICE itself is pushing for more and more secrecy. The agency often refuses or fails to respond to Freedom of Information Act requests, leading news outlets and other requesters to sue. It illegally attempted to curtail congressional visits to ICE facilities, and then apparently quickly and quietly rescinded that guidance.

In May, ICE asked the San Francisco Standard to blur the faces of ICE agents whose pictures were taken in public during an operation at a courthouse. The Standard refused and then reported on the request under the headline, “The ICE agents disappearing your neighbors would like a little privacy, please.”

Last week, ICE agents in New York reportedly harassed journalists attempting to cover immigration court proceedings, including by photographing their press credentials.

Perhaps most disturbingly, ICE is currently attempting to deport Mario Guevara, a journalist known for documenting immigration raids, after he was arrested on unjustified charges while covering a “No Kings” protest in Georgia. Guevara now faces the prospect of being returned to El Salvador, a country he left after receiving death threats for his reporting.

He’s been granted bond, but the government alarmingly argued that his livestreaming of a protest justifies deporting him because he publicized law enforcement activities (which is what journalists are supposed to do).

In addition to using deportations to punish reporting, the administration is also targeting opinion writing. It’s currently attempting to deport Tufts University student Rümeysa Öztürk over an op-ed she co-wrote.

These potential deportations send a chilling message to other journalists who’ve fled to the United States from repressive countries. As one reporter told The New Yorker about Guevara’s case, “Today, it was Mario, but tomorrow it could be any one of us.” And while noncitizen journalists are the easiest targets for now, it’s abundantly clear that the government would like to criminalize journalists it doesn’t like, regardless of the journalists’ residency status.

Yet many journalists — like those at the Standard — are refusing to be chilled. Reporters, many at smaller news outlets, have kept reporting on ICE raids in their communities, often relying on video or photos of ICE agents in public captured by the public and posted on social media—videos that Homan and Leavitt would probably claim should be illegal.

Continuing to report and inform the public is exactly the right response to the government’s attempts to intimidate the press from reporting on ICE. But journalists can’t push back on these chilling tactics alone.

“See something, say something” shouldn’t just be a motto for the security state. When you see these chilling tactics employed by the government against the free press, speak up against it—to other journalists, on op-ed pages and in letters to the editor, to ICE, to your state and local representatives, and to Congress.

freedom.press/issues/ice-wants…

[Bogdan Micea] uses a laptop cooler, but was a bit annoyed that his cooler would run at the same power no matter how hard the laptop was working. Rather than keep adjusting the cooler’s power manually, he automated it by installing an Arduino Pro Micro as a controller in the cooler and writing a Rust controller application for his computer.

[Bogdan]’s cooler is controlled by four buttons, which can have different functions depending on how long they’re pressed. After mapping out their functionality and minor quirks, [Bogdan] soldered four transistors in parallel with the buttons to let the Arduino simulate button presses; another four Arduino pins accept input from the buttons to monitor their state. The Arduino USB port connects to the cooler’s original USB power input, so the cooler looks superficially unchanged. When the cooler starts up, the Arduino sets it to a known state, then monitors the buttons. Since it can both monitor and control the buttons, it can notify the computer when the cooler’s state changes, or change the state when the computer sends a command.

On the computer’s part, the control software creates a system tray that displays and allows the user to change the cooler’s current activity. The control program can detect the CPU’s temperature and adjust the cooler’s power automatically, and the Arduino can detect the laptop’s suspend state and control power accordingly.

Somewhat surprisingly, this seems to be the first laptop cooler we’ve seen modified. We have seen a laptop cooler used to overclock a Teensy, though, and a laptop’s stock fans modified.

hackaday.com/2025/07/02/making…

È stato scoperto sul sistema operativo Microsoft Windows un nuovo metodo per aggirare la protezione che consente l’esecuzione di script dannosi senza alcun preavviso all’utente. La tecnica, chiamata FileFix, è stata migliorata e ora sfrutta una vulnerabilità nel modo in cui i browser gestiscono le pagine HTML salvate.

L’attacco è stato presentato da un ricercatore di sicurezza noto come mr.d0x. Aveva precedentemente illustrato il funzionamento della prima versione di FileFix. All’epoca, gli aggressori utilizzavano una pagina di phishing per convincere la vittima a incollare un comando PowerShell mascherato nella barra degli indirizzi di Windows Explorer. Una volta incollato, il comando veniva eseguito automaticamente, rendendo l’attacco praticamente invisibile all’utente.

La nuova variante di FileFix è ancora più sofisticata. Permette l’esecuzione dello script dannoso, bypassando la protezione Mark of the Web ( MoTW ), progettata per bloccare l’esecuzione di file potenzialmente pericolosi scaricati da Internet. In questo attacco, l’aggressore utilizza tecniche di ingegneria sociale per convincere la vittima a salvare una pagina HTML utilizzando la scorciatoia da tastiera Ctrl+S e rinominarne l’estensione in .HTA. Tali file sono associati alla tecnologia obsoleta, ma ancora disponibile in Windows, delle applicazioni HTML.

I file con estensione .HTA sono applicazioni basate su HTML che vengono avviate automaticamente tramite il componente di sistema mshta.exe. Questo file eseguibile legittimo consente di eseguire codice HTML e script incorporati con i diritti dell’utente corrente. Questo è ciò che rende i file .HTA uno strumento utile per la distribuzione di codice dannoso.

Come mostrato da mr.d0x, quando si salva una pagina HTML tramite un browser nel formato “Pagina web completa” (con tipo MIME text/html), tale pagina non riceve la speciale etichetta di sicurezza MoTW. MoTW viene solitamente aggiunta automaticamente ai file scaricati da Internet per avvisare l’utente di una potenziale minaccia e bloccare l’esecuzione di script incorporati. L’assenza di questa etichetta offre agli aggressori la possibilità di aggirare i meccanismi di sicurezza standard del sistema.

Una volta che l’utente rinomina il file salvato, ad esempio in “MfaBackupCodes2025.hta”, e lo apre, il codice dannoso incorporato nel file verrà immediatamente eseguito senza alcun avviso o richiesta di sistema. In sostanza, la vittima esegue il malware autonomamente, senza nemmeno rendersene conto.

La parte più difficile per gli aggressori è la fase di ingegneria sociale: convincere l’utente a salvare la pagina e modificarne correttamente l’estensione. Tuttavia, come osserva mr.d0x, questa barriera può essere superata se la pagina falsa è progettata correttamente. Ad esempio, potrebbe apparire come un sito web ufficiale, chiedendo all’utente di salvare i codici di backup per l’autenticazione a due fattori per ripristinare l’accesso all’account in un secondo momento. La pagina potrebbe contenere istruzioni dettagliate, tra cui la richiesta di premere Ctrl+S, selezionare l’opzione di salvataggio “Pagina web, completa” e specificare un nome file con estensione .HTA.

Se una pagina di questo tipo sembra sufficientemente convincente e l’utente non ha conoscenze approfondite in materia di sicurezza e non nota l’estensione del file, la probabilità di un attacco riuscito aumenta significativamente. Ad esempio, gli aggressori potrebbero utilizzare una pagina intitolata “Codici di backup MFA” che suggerisce di salvare un file con il nome “MfaBackupCodes2025.hta”. Questo approccio è particolarmente pericoloso, dato il basso livello di formazione tecnica di molti utenti.

Per proteggersi da tali attacchi, gli esperti raccomandano di eliminare completamente o bloccare il file eseguibile di sistema mshta.exe, che si trova nelle directory C:WindowsSystem32 e C:WindowsSysWOW64. Questo componente non viene praticamente utilizzato nelle attività quotidiane e può essere disabilitato in sicurezza nella maggior parte degli scenari.

L'articolo FileFix aggira la protezione Mark of the Web di Microsoft Windows proviene da il blog della sicurezza informatica.

Some time ago, Linus Torvalds made a throwaway comment that sent ripples through the Linux world. Was it perhaps time to abandon support for the now-ancient Intel 486? Developers had already abandoned the 386 in 2012, and Torvalds openly mused if the time was right to make further cuts for the benefit of modernity.

It would take three long years, but that eventuality finally came to pass. As of version 6.15, the Linux kernel will no longer support chips running the 80486 architecture, along with a gaggle of early “586” chips as well. It’s all down to some housekeeping and precise technical changes that will make the new code inoperable with the machines of the past.

Why Won’t It Work Anymore?

The kernel has had a method to emulate the CMPXCH8B instruction for some time, but it will now be deprecated.
The big change is coming about thanks to a patch submitted by Ingo Molnar, a long time developer on the Linux kernel. The patch slashes support for older pre-Pentium CPUs, including the Intel 486 and a wide swathe of third-party chips that fell in between the 486 and Pentium generations when it came to low-level feature support.

Going forward, Molnar’s patch reconfigures the kernel to require CPUs have hardware support for the Time Stamp Counter (RDTSC) and CMPXCHG8B instructions. These became part of x86 when Intel introduced the very first Pentium processors to the market in the early 1990s. The Time Stamp Counter is relatively easy to understand—a simple 64-bit register that stores the number of cycles executed by the CPU since last reset. As for CMPXCHG8B, it’s used for comparing and exchanging eight bytes of data at a time. Earlier Intel CPUs got by with only the single-byte CMPXCHG instruction. The Linux kernel used to feature a piece of code to emulate CMPXCHG8B in order to ease interoperability with older chips that lacked the feature in hardware.

The changes remove around 15,000 lines of code. Deletions include code to emulate the CMPXCHG8B instruction for older processors that lacked the instruction, various emulated math routines, along with configuration code that configured the kernel properly for older lower-feature CPUs.

Basically, if you try to run Linux kernel 6.15 on a 486 going forward, it’s just not going to work. The kernel will make calls to instructions that the chip has never heard of, and everything will fall over. The same will be true for machines running various non-Pentium “586” chips, like the AMD 5×86 and Cyrix 5×86, as well as the AMD Elan. It’s likely even some later chips, like the Cyrix 6×86, might not work, given their questionable or non-existent support of the CMPXCHG8B instruction.

Why Now?

Molnar’s reasoning for the move was straightforward, as explained in the patch notes:

In the x86 architecture we have various complicated hardware emulation
facilities on x86-32 to support ancient 32-bit CPUs that very very few
people are using with modern kernels. This compatibility glue is sometimes
even causing problems that people spend time to resolve, which time could
be spent on other things.

Indeed, it follows on from earlier comments by Torvalds, who had noted how development was being held back by support for the ancient members of Intel’s x86 architecture. In particular, the Linux creator questioned whether modern kernels were even widely compatible with older 486 CPUs, given that various low-level features of the kernel had already begun to implement the use of instructions like RDTSC that weren’t present on pre-Pentium processors. “Our non-Pentium support is ACTIVELY BUGGY AND BROKEN right now,” Torvalds exclaimed in 2022. “This is not some theoretical issue, but very much a ‘look, ma, this has never been tested, and cannot actually work’ issue, that nobody has ever noticed because nobody really cares.”
Intel kept i486 chips in production for a good 18 years, with the last examples shipped out in September 2007. Credit: Konstantin Lanzet, CC BY-SA 3.0
Basically, the user base for modern kernels on old 486 and early “586” hardware was so small that Torvalds no longer believed anyone was even checking whether up-to-date Linux even worked on those platforms anymore. Thus, any further development effort to quash bugs and keep these platforms supported was unjustified.

It’s worth acknowledging that Intel made its last shipments of i486 chips on September 28, 2007. That’s perhaps more recent than you might think for a chip that was launched in 1989. However, these chips weren’t for mainstream use. Beyond the early 1990s, the 486 was dead for desktop users, with an IBM spokesperson calling the 486 an “ancient chip” and a “dinosaur” in 1996. Intel’s production continued on beyond that point almost solely for the benefit of military, medical, industrial and other embedded users.
Third-party chips like the AMD Elan will no longer be usable, either. Credit: Phiarc, CC-BY-SA 4.0
If there was a large and vocal community calling for ongoing support for these older processors, the kernel development team might have seen things differently. However, in the month or so that the kernel patch has been public, no such furore has erupted. Indeed, there’s nothing stopping these older machines still running Linux—they just won’t be able to run the most up-to-date kernels. That’s not such a big deal.

While there are usually security implications around running outdated operating systems, the simple fact is that few to no important 486 systems should really be connected to the Internet anyway. They lack the performance to even load things like modern websites, and have little spare overhead to run antiviral software or firewalls on top of whatever software is required for their main duties. Operators of such machines won’t be missing much by being stuck on earlier revisions of the kernel.

Ultimately, it’s good to see Linux developers continuing to prune the chaff and improve the kernel for the future. It’s perhaps sad to say goodbye to the 486 and the gaggle of weird almost-Pentiums from other manufacturers, but if we’re honest, few to none were running the most recent Linux kernel anyway. Onwards and upwards!

hackaday.com/2025/07/02/why-th…