Introduction

Cybercriminals who specialize in ransomware do not always create it themselves. They have many other ways to get their hands on ransomware samples: buying a sample on the dark web, affiliating with other groups or finding a (leaked) ransomware variant. This requires no extraordinary effort, as source code is often leaked or published. With a set of standard tools and a freshly built (and sometimes slightly altered) ransomware sample, victims can be sought, and the malicious activity can spread.

In the past months, we released several private reports detailing exactly this. You will find a few excerpts from these below. To learn more about our crimeware reporting service, contact us at crimewareintel@kaspersky.com.

SEXi

This past April, IxMetro was hit by an attack that used a still-new ransomware variant dubbed “SEXi”. As the name suggests, the group focuses primarily on ESXi applications. In each of the cases we investigated, the victims were running unsupported versions of ESXi, and there are various assumptions about the initial infection vector.

The group deploys one of two types of ransomware variants depending on the target platform: Windows or Linux. Both samples are based on leaked ransomware samples, namely Babuk for the Linux version and Lockbit for Windows. This is the first time we’ve seen a group use different leaked ransomware variants for their target platforms.

Another thing that sets this group apart is their contact method. Attackers will typically leave a note with an email address or leak site URL in it, but in this case, the note contained a user ID associated with the Session messaging app. The ID belonged to the attackers and was used across different ransomware attacks and victims. This signifies a lack of professionalism, as well as the fact that the attackers did not have a TOR leak site.

Key Group

While the SEXi group has employed leaked ransomware variants from two malware families, other groups have taken this approach to a whole different level. For example, Key Group, aka keygroup777, has used no fewer than eight different ransomware families throughout their relatively short history (since April 2022) – see the image below.

Use of leaked ransomware builders by Key Group

We were able to link different variants to Key Group by their ransom notes. In a little over two years that the group has been active, they have adjusted their TTPs slightly with each new ransomware variant. For example, the persistence mechanism was always via the registry, but the exact implementation differed by family. Most of the time, autorun was used, but we’ve also seen them using the startup folder.

For example, UX-Cryptor added itself to the registry as shown below.
HKU\$usersid\Software\Microsoft\Windows NT\CurrentVersion\Winlogon
"Shell" = "$selfpath"
HKU\$usersid\Software\Microsoft\Windows\CurrentVersion\Run
"WindowsInstaller" = "$selfpath -startup"
"MSEdgeUpdateX" = "$selfpath"
HKU\$usersid\Software\Microsoft\Windows\CurrentVersion\RunOnce
"System3264Wow" = "$selfpath --init"
"OneDrive10293" = "$selfpath /setup"
"WINDOWS" = "$selfpath --wininit"
While the Chaos ransomware variant copied itself to
$user\$appdata\cmd.exe and launched a new process, the new process in turn created a new file in the startup folder: $user\$appdata\Microsoft\Windows\Start Menu\Programs\Startup\cmd.url. This contained the path to the ransomware file: URL=file:///$user\$appdata\cmd.exe.
Russian-speaking groups typically operate outside of Russia, but Key Group is an exception to this rule. Their operations are not very professional, as well as SEXi’s, and show a lack of comprehensive skills. For example, the main C2 channel is a GitHub repository, which makes them easier to track, and communication is maintained over Telegram rather than a dedicated server on the TOR network.

Mallox

Mallox is another relatively new ransomware variant that first came to light in 2021 and kicked off an affiliate program in 2022. The way the authors obtained the source code is unclear — they could have written it from scratch, used a published or a leaked one, or purchased it, as they claim. Since Mallox is a lesser-known and hence, also less-documented, ransomware variant compared to the likes of Lockbit and Conti, we decided to cover Mallox in this post.

Although starting as a private group conducting their own campaigns, Mallox launched an affiliate program shortly after inception. Interestingly, the group only wants to do business with Russian-speaking affiliates and not with English-speaking ones, they do not welcome novices as well. They are also very explicit about what types of organizations affiliates should infect: no less than $10 million in revenue and no hospitals or educational institutions.

Mallox uses affiliate IDs, making it possible to track affiliate activity over the course of time. In 2023, there were 16 active partners, which explains the spike in activity, most notably in the spring and autumn of 2023 as evidenced by the PE timestamp.

Number of discovered Mallox samples by PE timestamp (download)

In 2024, only eight of the original affiliates were still active, with no newcomers. Aside from this, Mallox has all the typical Big Game Hunting attributes that other groups also have, such as a leak site, a server hosted on TOR, and others.

Conclusion

Getting into the ransomware business has never been too difficult. Of-the-shelf solutions have been available, or else one could become an affiliate and outsource many tasks to others. Initially, with tools like Hidden Tear, the impact was relatively low: the tools were easy to detect and contained implementation errors, which helped decryption. They targeted regular consumers rather than large organizations. This has changed these days, as the impact can be much bigger with the advent of the Big Game Hunting era and the release of “professional” ransomware variants, which can affect entire companies, organizations, hospitals and so on. Such samples are more efficient in terms of speed, configurability, command line options, platform support and other features. That said, while getting your hands on a “professional” ransomware variant might be easy, the whole process of exploiting and exploring an organization can be quite time consuming, if not impractical, for newbies.

We also see that groups using leaked variants seldom look professional, with Key Group and SEXi among the examples of this. The reason why they are effective is either that they are able to set up a successful affiliate scheme (Key Group), or that they have found a niche where they can deploy their ransomware effectively (SEXi). In these two scenarios, the leaking or publication of ransomware variants can be considered a threat to organizations and individuals.

If you would like to stay up to date on the latest TTPs being used by criminals, or if you have questions about our private reports, contact us at crimewareintel@kaspersky.com.

Indicators of compromise

SEXi
4e39dcfb9913e475f04927e71f38733a
0a16620d09470573eeca244aa852bf70

Key Group
bc9b44d8e5eb1543a26c16c2d45f8ab7
acea7e35f8878aea046a7eb35d0b8330

Mallox
00dbdf13a6aa5b018c565f4d9dec3108
01d8365e026ac0c2b3b64be8da5798f2

securelist.com/sexi-key-group-…

Photons are particles of light, or waves, or something like that, right? [Mithuna Yoganathan] explains this conundrum in more detail than you probably got in your high school physics class.

While quantum physics has been around for over a century, it can still be a bit tricky to wrap one’s head around since some of the behaviors of energy and matter at such a small scale aren’t what we’d expect based on our day-to-day experiences. In classical optics, for instance, a brighter light has more energy, and a greater amplitude of its electromagnetic wave. But, when it comes to ejecting an electron from a material via the photoelectric effect, if your wavelength of light is above a certain threshold (bigger wavelengths are less energetic), then nothing happens no matter how bright the light is.

Scientists pondered this for some time until the early 20th Century when Max Planck and Albert Einstein theorized that electromagnetic waves could only release energy in packets of energy, or photons. These quanta can be approximated as particles, but as [Yoganathan] explains, that’s not exactly what’s happening. Despite taking a few classes in quantum mechanics, I still learned something from this video myself. I definitely appreciate her including a failed experiment as anyone who has worked in a lab knows happens all the time. Science is never as tidy as it’s portrayed on TV.

If you want to do some quantum mechanics experiments at home (hopefully with more luck than [Yoganathan]), then how about trying to measure Planck’s Constant with a multimeter or LEGO? If you’re wondering how you might better explain electromagnetism to others, maybe this museum exhibit will be inspiring.

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Standardization might sound boring, but it’s really a great underlying strength of modern society. Everyone agreeing on a way that a certain task should be done saves a lot of time, energy, and money. But it does take a certain amount of consensus-building, and at the time [JC]’s HVAC system was built the manufacturers still hadn’t agreed on a standard control scheme for these machines yet. But with a little ingenuity and an Arduino, the old HVAC system can be given a bit of automatic control.

The original plan for this antiquated system, once off-the-shelf solutions were found to be incompatible, was to build an interface for the remote control. But this was going to be overly invasive and complex. Although the unit doesn’t have a standard remote control system, it does have extensive documentation so [JC] was able to build a relay module for it fairly easily with an Arduino Nano Matter to control everything and provide WiFi functionality. It also reports the current status of the unit and interfaces with the home automation system.

While some sleuthing was still needed to trace down some of the circuitry of the board to make sure everything was wired up properly, this was a much more effective and straightforward (not to mention inexpensive) way of bringing his aging HVAC system into the modern connected world even through its non-standardized protocols. And, although agreeing on standards can sometimes be difficult, they can also be powerful tools once we all agree on them.

Many makers start by building mock-ups from cardboard, but [Alex-08] has managed to build an R/C plane that actually flies, out of cardboard.

If you’ve been thinking of building an R/C plane from scratch yourself, this guide is an excellent place to start. [Alex-08] goes through excruciating detail on how he designed and constructed this marvel. The section on building the wings is particularly detailed since that’s the most crucial element in making sure this plane can get airborne.

Some off-the-shelf R/C parts and 3D printed components round out the parts list to complement the large cardboard box used for most of the structural components. The build instructions even go through some tips on getting that vintage aircraft feel and how to adjust everything for a smooth flight.

Need a wind tunnel instead? You can build that out of cardboard too. If paper airplanes are more your thing, how about launching them from space? And if you’re just trying to get a head start on Halloween, why not laser cut an airplane costume from cardboard?

[Aaron Lager]’s Pi-O-Scope-Pong project takes a minimal approach to Pong by drawing on an oscilloscope to generate crisp paddles and ball. A Raspberry Pi takes care of the grunt work of signal generation, and even uses the two joysticks of an Xbox controller (connected to the Pi over Bluetooth) for inputs.

Originally, [Aaron] attempted to generate the necessary signals directly from the Pi’s PWM outputs by doing a little bit of RC filtering on the outputs, but was repulsed by the smeary results. The solution? An old but perfectly serviceable 8-bit MAX506 DAC now handles crisping up the visuals with high-quality analog outputs. Code is available on the project’s GitHub repository.

There isn’t any score-keeping or sound, but one thing that it has over the original Pong is a round ball. The ball in the original Pong game was square, but mainly because cost was a concern during design and generating a round ball would have ballooned the part count.

In many ways, Pong itself is a great inspiration for the Tiny Games Challenge, because the simplicity of its gameplay was likely a big part of its success.

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