Like a sleeper cell awaiting activation, a never-before-seen Windows backdoor dubbed Sleepwalker waits silently in memory for one specifically crafted network packet to wake it up and deliver commands using the malware's 23-instruction language. The commands can do everything from running code directly in memory to moving data off the computer. Malware researcher Dominik Reichel discovered the passive backdoor, which also has its own command language, and detailed Sleepwalker in a technical analysis on Monday. “What makes it worth writing up is what that packet carries: not a readable command, but a short program written in a command language of the backdoor’s own design,” Reichel said. “Its 23 instructions cover scheduling, several ways to move data, staged file delivery and running code directly in memory. Recovering the encryption key is not enough to understand one of these programs. The internal command language must be reverse engineered as well.” In addition to having its own command language, it's also notable that the remote host can be a VMware VMCI target instead of a normal network address. “Taken as a whole, the approach here is consistent with a targeted, well-resourced operation rather than an opportunistic one,” Reichel wrote. The malware, hidden inside a 64-bit Windows DLL file, impersonates Microsoft's dpapi.dll, part of Windows' data protection API for protecting sensitive data. It exports the same seven functions as the real dpapi.dll, but attempts to forward calls to a file named dpapisvc.dll, which is not a real Windows component. The file also has a forged ESET Management Agent version resource, and loads via side-loading into ERAAgent.exe, the Windows executable for ESET Management Agent. After confirming that its host process is named ERAAgent.exe, Sleepwalker goes to sleep inside the computer's memory, which also helps it remain hidden from traditional anti-virus tools. Unlike most backdoors, which call back to an attacker-controlled command-and-control (C2) server and start receiving commands, Sleepwalker lies in wait, checking every packet that passes through the network looking for a specific pattern - this is called a magic packet. Once it sniffs out a packet that matches the exact pattern, the backdoor decrypts the data and treats it as a command. “Because the backdoor never sends anything out on its own and does not open any obvious listening port by default, tools that watch for connections to known-bad domains or unusual outbound traffic will not see anything unusual,” Reichel wrote. “The absence of outbound connections to known-bad infrastructure does not rule out an infection, either. A machine can be fully compromised by this backdoor while producing nothing at all for a network monitor to flag.” Hidden commands Every command sent to the backdoor is encrypted using AES-256-CCM, and the command language is unique in that, once decrypted, it is neither text nor a document. Instead, each command is a short sequence of raw bytes, and it only makes sense when read in a specific order. Reichel’s write-up includes a key that shows how to read the bytes, and each of Sleepwalker’s 23 instructions is written in this command language. Some of the instructions carry an inner program. For example, a scheduler can also contain a network listener, with a routine that waits for a particular file to be assembled and checked before it will run on the compromised computer. Beyond the two magic-packet sniffing instructions and basic instructions - such as an exit command that stops all running programs and the packet listener, and an instruction that starts a second, smaller program running concurrently with the parent program - the backdoor has multiple others. These include four instructions on sending and hiding data. One of these opens a TCP connection to a chosen address and port, and then sends a block of data to a remote host, which can be a VMware VMCI target instead of a normal network address. Another one writes a block of data to a Windows named pipe on a chosen computer, and can optionally log in with a username and password first. Five other instructions focus on inbound task reception, such as waiting to receive - or reaching out on its own - a follow-up instruction, opening a TCP or UDP port, or creating and/or connecting to a named pipe. Additionally, the malware has five different instructions on building and running programs. A lot of unknowns…and detection tools As Reichel notes, however, a lot remains unknown about Sleepwalker. “I have no collection context tying the file to a confirmed intrusion, so I cannot identify a victim, industry, country or affected organization,” he wrote. While we know that the DLL is designed to execute via side-loading after being placed beside ERAAgent.exe, we don't know how the malware operator first gained access to the computer or delivered the malicious file. We also don’t know the operator or developer, or what post-compromise activity, if any, took place. “I found no related code that would support attribution to a known group, and this one sample cannot establish when or how widely Sleepwalker was deployed, whether variants exist or whether it belongs to a continuing campaign,” Reichel wrote. Perhaps most importantly, for anyone who believes that they may be infected with Sleepwalker or a related malware sample, Reichel wrote, “I have created a toolkit to help decode its bytecode, examine encrypted and network artifacts, summarize behavior and indicators and safely reproduce its receiving pipeline without executing commands or transmitting traffic,” urging targeted individuals to contact him. He also created a mitigation guide, with a remediation script for use after Sleepwalker is detected.®
If you're curious how easily tech companies can fingerprint your browser and device and potentially single them out from the crowd, a new utility Glassbox will show you. Aside from pinging a public geolocation API, it runs entirely in a user’s browser and doesn’t ship any info out to the web while acting just like all the various trackers, anti-fraud scripts, and other browser fingerprinting tricks one is likely to encounter online. Unlike some other available tools that do the same, Glassbox provides a whole bunch of raw, unfiltered data you can sift through to see what makes your browser stand out, along with an estimate of how identifiable its fingerprint may be. In this vulture’s testing, Glassbox's estimate ranged from 99 percent in the Chrome window I use daily for work to a low of 56 percent in Tor Browser with an active circuit. “The ‘identifiability’ number is an honest model, not a measurement,” Glassbox developer David Dale said of his tool in a Hacker News thread. “It sums published per-signal entropy, discounts your browser masks, and caps at the ~33 bits needed to single out one person on Earth.” Dale added in the thread that, since it runs locally, that identifiability number is an estimate, as Glassbox doesn’t have a live population to pull against. AmIUnique and the EFF’s Cover Your Tracks, the other tools mentioned above, provide real population numbers, he noted. Dale got the idea for GlassBox after learning about silent sawtooth waves used by fingerprinting code found on Alibaba's AliExpress site to identify browsers using audio. Rather than fork one of the existing open source tools - both EFF's Cover Your Tracks and AmIUnique have GitHub repos - he decided to build his own, with some help from AI. “I'm a solo entrepreneur and long-time security engineer; tools like Claude Code have made it much easier to polish ideas and offer the useful ones to a wider audience,” Dale told us in an email. “I knew a fair number of fingerprinting methods but not that one, and I wanted to see all of them in one place, running against my own browser,” he said on Hacker News. In other words, Glassbox factors Alibaba’s tricks into its identifiability estimates alongside 30 other probes for unique browser data - things like canvas, WebGL, font libraries, WASM features, API matrices, and cross-site login states. According to Glassbox, my particular Chrome session I use for work is unique to around 1 in 7.6 billion browsers, and my IP address narrows that further (my ISP apparently uses IPv6, making me even more identifiable). As for which browsers appear to be safer, I have Safari, Edge, Firefox, and Tor on my machine alongside Chrome; Firefox and Tor are the only ones that didn’t label me “effectively unique,” giving me estimated identifiability ratings of 89 and 56 percent, respectively. What that means is that I share the same fingerprint as 1 in 681 million Firefox users and 1 in 408 thousand Tor users - that still doesn’t exactly make me a ghost online, but it definitely puts me in a pool much larger than Chrome, Edge, or Safari. Again, those are estimates, Dale reminded us, not a hard truth as, he says, “a no-server tool [can’t] measure true rarity.” “The single highest-impact move is to use a browser that puts you in a large, identical crowd,” Dale explained in an email. “Counterintuitively, a heavily customized ‘hardened’ setup often makes you more identifiable, because almost nobody else looks exactly like it. Blending in beats standing out.” Aside from using a browser that does a good job of obfuscating its user, Dale said a VPN or Tor is a must, as is finding a way to close the WebRTC leak that has long dogged internet users and leaves browsers identifiable through some VPNs thanks to being enabled by default in most web browsers. Glassbox includes a page of suggestions for how to anonymize yourself online, and let’s face it: With everything from invisible pixels to silent sound waves doing their damndest to figure out who’s behind a browser in order to make money off them, that’s more important than ever. ®
A suspected Iran-linked cyberattack shut down a small UK power plant around the time that a series of digital intrusions disrupted American water utilities across 12 states. A British government spokesperson confirmed the hack to The Register on Monday and told us that the security incident affected a “small-scale energy generator.” “At no point was there a risk to the wider energy system,” the spokesperson said, adding that the UK’s energy system is “highly resilient,” and that the government works “closely with the energy sector to protect infrastructure.” In a series of xeets about the cyberattack, UK Energy Minister Michael Shanks said that his department briefed energy CEOs after the incident and “shared further advice with companies on the steps they should take to stay secure.” Government officials did not disclose which power station shut down, and the UK has not formally attributed the cyberattack to Iran - or any other government or hacking group. The Telegraph, which first reported the news, said that the incident shut down the power plant for four days in what is believed to be the first disruptive Iranian cyberattack of its kind in the UK. In late July, suspected Iranian cyber operatives disrupted more than 30 water facilities in Minnesota, with similar intrusions subsequently reported across at least 11 other US states. While neither state nor federal officials have attributed these hacks to Iran, private-sector threat analysts have told The Register that Iran is “almost certainly” behind these breaches, which are a direct response to the ongoing Middle East conflict. While these earlier water-system intrusions didn’t appear to have an AI assist - most or all of the American utility cyberattacks involved internet-connected programmable logic controllers (PLCs) - last week the feds warned that attackers are now using AI-generated exploitation scripts to break into internet-exposed Siemens S7 Series PLCs at water, manufacturing, energy, and other critical facilities. “This is not a theoretical risk – it is an active threat,” the FBI and four other federal agencies warned. “This appears to be a continuation of the same suite of activity we suspect is affiliated with Iran targeting PLCs,” Cynthia Kaiser, Halcyon Ransomware Research Center SVP and a former FBI cyber analyst, told The Register. “Iran-affiliated actors and adversaries are actively targeting a wide swath of operational technology because these PLCs underpin essential health, safety, and critical infrastructure across society,” Kaiser said. ®
Developer Matt Callaghan claims he caught Alibaba's B2C website, AliExpress, trying to track web users by playing sounds through browsers vulnerable to audio fingerprinting. The software engineer drew attention to the issue late last week after investigating why his Bluetooth headphones stopped playing music whenever he visited the AliExpress website. “Recently I ran into a strange problem with my Bluetooth headphones,” Callaghan wrote. “They support multipoint Bluetooth audio, so they can be connected to my PC and phone at the same time. Normally, the PC takes priority playing audio, with my phone being able to play audio when nothing is playing on the PC. “Usually I listen to music on my phone but with notifications or YouTube playing through the PC, this works reliably until I open an AliExpress page in Firefox or Chrome. “Shortly after loading the AliExpress homepage, audio from my phone would stop playing. Closing the AliExpress tab fixes it immediately. Muting the tab/Firefox/Windows does not help, and there is no visible video, music, or other media playing on the page.” Callaghan tried to find any hidden conventional media elements but found nothing. Further digging revealed two audio scripts that he said were “extremely obfuscated” within AliExpress's browser security and anti-abuse tooling. He said the scripts built a WebAudio graph that introduced a sawtooth oscillator to generate a waveform, an analyzer to measure the result after the waveform passes through a browser’s audio implementation, and a script to read the associated frequency data. The scripts set the audio’s gain to zero, meaning the end user won’t hear anything, but the WebAudio graph will still be processed by the browser. “This is very different from an autoplaying video,” said Callaghan. “There is no media element for the browser's normal tab mute control to stop. As far as the page is concerned, it is performing live audio processing. “In my case, that appears to have been enough for Firefox or Windows to keep the Bluetooth audio path active, preventing my multipoint headphones from switching cleanly back to the phone.” Callaghan found further evidence in the code looking for data related to screen dimensions, device memory, browser plugins, WebGL rendering, mouse events, and more. As well as signs that AliExpress is encrypting data and sending it to its telemetry services, the developer said all of it amounts to “a fairly comprehensive browser and device fingerprint.” The Register has asked Alibaba to comment. Despite Callaghan saying he could reliably reproduce this issue on both Firefox and Chrome, Firefox issued a Xtatement saying its anti-fingerprinting technology thwarts AliExpress’ tracking tricks. It pointed to a blog post from Tom Ritter, a security engineer on the Firefox team, who explained that as of version 118 (September 2023), the protections it introduced eliminated the efficacy of WebAudio-based fingerprinting. These protections are not designed to stifle fingerprinting efforts at the source. Instead, they work to group all users together, making it look like all fingerprinted users are the same, effectively nullifying the tracking attempts. For 99.24 percent of users, they fall into one of three “buckets” – user categories delineated by types of hardware. The vast majority fall into buckets one and two: Bucket one: x86/x64 CPUs lacking FMA (Fused Multiply-Add) instructions Bucket 2: x64 CPUs with FMA instructions And for the remaining 0.76 percent, the fingerprinting script failed entirely, according to Firefox’s data. However, Ritter said there are 48 users worldwide who do not fall into the three buckets, or the 0.76 percent whose machines did not allow the scripts to run. These 48 users fell into 23 other minuscule buckets, which means they are not grouped into the masses like the rest, and so fingerprinting is more effective on this vast minority of users. “This is very unfortunate, as it makes these users completely unique, but it is also not terribly unusual - computers are weird and these results could have been caused by bad RAM, a CPU bug, or possibly some crazy architecture (LoongArch??),” said Ritter. “But at the end of the day, WebAudio fingerprinting is nearly useless. I don't expect browser fingerprinting to disappear from websites entirely (unless some regulatory action occurs, fingers crossed) - it's still going to be effective against a majority of users on the web, but at least for privacy-focused browsers, it should be wildly less effective.” Brave, maker of the eponymous privacy-centric browser, also Xeeted a response to Calalghan’s findings, saying it has protected users from fingerprinting for six years. “Brave injects random data into the browser's output so you show a different fingerprint to different sites. This fingerprint also resets across sessions. “For added protection, we also block the specific scripts used by AliExpress for the tracking method mentioned above. Again, this is done by default for all Brave users. You don't have to change any settings to be shielded from this audio fingerprinting.” Ritter said Chrome and Safari “probably have defenses against this [brand of fingerprinting].” Safari deploys Advanced Tracking and Fingerprinting Protection to prevent WebAudio-based tracking and other methods of fingerprinting. It works differently to Firefox, though, injecting audio errors into an audio buffer, instead of trying to lump all users into an identical bucket. Chrome, on the other hand, does not aggressively protect users from fingerprinting, as privacy consultant Alexander Hanff said earlier in the year. "There are at least thirty distinct fingerprinting techniques that work in Chrome right now, today, as you read this," he wrote. "Not theoretical attacks from academic papers that might work under laboratory conditions – real, production techniques deployed on millions of websites to identify and track you without your knowledge or consent." ® Updated 08/25 at 1805 GMT to clarify the behavior was observed on AliExpress, which is Alibaba's B2C web site for small-scale purchases.
Are you sick and tired of maintaining a password manager? Struggling with choosing the right one for you? Well, readers who live Down Under can get themselves down to their local AusPost branch where they can pick up an old-school alternative for just AU$4.90 (US$3.51). Password books are something of a historical relic, phased out largely because of the scrutiny associated with using one and the now-gray-haired elders who once scoffed at the mere notion of such an opsec crime. They might not be able to suggest a strong password for each of your many online accounts, and they won’t do you much good if your house is burgled, but you could argue that there is still value to be found in a pen-and-paper password vault. That’s exactly the conclusion drawn by the thousands of social media users who flocked to a post this week from one Australian who found stacks of password books for sale in their local post office. Small books are priced at AU$4.90 (US$3.51), while larger options will set you back a dollar extra. Granted, there are myriad issues associated with relying on a physical document for digital account security. For one, it’s a single point of failure. Lose the book or have it stolen, and it’s a painful road to restoring access to all your accounts. One could argue that if it’s kept inside the home and it’s stolen, then you’ve got bigger problems on your hands, but perhaps that’s not as true nowadays, when so many of our valuables are either stored or primarily accessed online. That said, it might bring a quick end to a hostage scenario – the type that is becoming all the more common as crypto wealth becomes increasingly common. Password books are also not as easily manageable as a modern password manager. The technological equivalent can auto-fill credentials, auto-update them if they’re found in public breaches, and suggest unique, strong strings to minimize the risk of compromise. You can’t store a passkey in a password book, either – a major issue now that the world is transitioning toward the new authentication standard. But using a password book no longer carries the same stigma as it once did among infosec types. The general consensus, gleaned from the hundreds of social media comments on the post, now seems to be that there's little wrong with storing passwords on paper at home. It’s certainly more secure than reusing the same weak password across multiple accounts, provided the book contains strong strings unique to each website. With the prevalence of infostealers nowadays, it's far more likely that crims will use a weak, reused, seldom-changed password to break into an online account than burgle a house to gain access to someone’s online banking. Plus, as many pointed out, it’s a much better route than writing passwords in a cloud document, which can be accessed by any device that has access to it – think Apple Notes, Google Docs, etc. At work, though, it’s probably best to stick to the password manager, the IT guys say. Mistakes by staff working at even the lowest rungs of the corporate ladder could lead to multimillion-dollar cyberattacks should that password book fall into the wrong hands. Pentesting consultants often send hired white hats to breach a company’s office and extract whatever value they can, sometimes through piss corridors. Such access can lead to malicious USB sticks dropping malware, bugs planted near the water fountain, and even someone stealing the password book from your desk drawer. Don’t believe it’s real? Security consultant Alethe Denis told us two years ago that’s exactly how her pentest team was able to surreptitiously extract corporate data over a company’s own Wi-Fi for over a week. They went dumpster diving, got the Wi-Fi creds, walked straight into a conference room, and deployed a data-stealing implant. In and out, all using physically stolen secrets. Helpful in the worst of times So, yes, password books contain plenty of potential pitfalls, Poignantly, however, they often prove invaluable in the event of a loved one’s passing. Having access to a password book, or at least some sort of plan to share passwords in the event of a death, is vital to ensuring family and friends have space to grieve without going through the arduous process of recovering an account through a platform provider, or via the courts. A slew of Redditors agreed, saying it made the whole process so much easier. One shared the tale of how their mother’s own special way of storing passwords resulted in a treasured family investigation. After password books spent years as outcasts of the cybersecurity world, they’re now having a second moment in the sun. And while the leading minds in cybersecurity are busy working on ways to stop phisherfolk from hacking into your accounts, or rogue AI agents from doing the same, there’s still something to celebrate in the safeguards of yesteryear, both in life and death. ®
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