Entries Tagged "malware"

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Using Legitimate GitHub URLs for Malware

Interesting social-engineering attack vector:

McAfee released a report on a new LUA malware loader distributed through what appeared to be a legitimate Microsoft GitHub repository for the “C++ Library Manager for Windows, Linux, and MacOS,” known as vcpkg.

The attacker is exploiting a property of GitHub: comments to a particular repo can contain files, and those files will be associated with the project in the URL.

What this means is that someone can upload malware and “attach” it to a legitimate and trusted project.

As the file’s URL contains the name of the repository the comment was created in, and as almost every software company uses GitHub, this flaw can allow threat actors to develop extraordinarily crafty and trustworthy lures.

For example, a threat actor could upload a malware executable in NVIDIA’s driver installer repo that pretends to be a new driver fixing issues in a popular game. Or a threat actor could upload a file in a comment to the Google Chromium source code and pretend it’s a new test version of the web browser.

These URLs would also appear to belong to the company’s repositories, making them far more trustworthy.

Posted on April 22, 2024 at 11:26 AM • View Comments

Backdoor in XZ Utils That Almost Happened

Last week, the Internet dodged a major nation-state attack that would have had catastrophic cybersecurity repercussions worldwide. It’s a catastrophe that didn’t happen, so it won’t get much attention—but it should. There’s an important moral to the story of the attack and its discovery: The security of the global Internet depends on countless obscure pieces of software written and maintained by even more obscure unpaid, distractible, and sometimes vulnerable volunteers. It’s an untenable situation, and one that is being exploited by malicious actors. Yet precious little is being done to remedy it.

Programmers dislike doing extra work. If they can find already-written code that does what they want, they’re going to use it rather than recreate the functionality. These code repositories, called libraries, are hosted on sites like GitHub. There are libraries for everything: displaying objects in 3D, spell-checking, performing complex mathematics, managing an e-commerce shopping cart, moving files around the Internet—everything. Libraries are essential to modern programming; they’re the building blocks of complex software. The modularity they provide makes software projects tractable. Everything you use contains dozens of these libraries: some commercial, some open source and freely available. They are essential to the functionality of the finished software. And to its security.

You’ve likely never heard of an open-source library called XZ Utils, but it’s on hundreds of millions of computers. It’s probably on yours. It’s certainly in whatever corporate or organizational network you use. It’s a freely available library that does data compression. It’s important, in the same way that hundreds of other similar obscure libraries are important.

Many open-source libraries, like XZ Utils, are maintained by volunteers. In the case of XZ Utils, it’s one person, named Lasse Collin. He has been in charge of XZ Utils since he wrote it in 2009. And, at least in 2022, he’s had some “longterm mental health issues.” (To be clear, he is not to blame in this story. This is a systems problem.)

Beginning in at least 2021, Collin was personally targeted. We don’t know by whom, but we have account names: Jia Tan, Jigar Kumar, Dennis Ens. They’re not real names. They pressured Collin to transfer control over XZ Utils. In early 2023, they succeeded. Tan spent the year slowly incorporating a backdoor into XZ Utils: disabling systems that might discover his actions, laying the groundwork, and finally adding the complete backdoor earlier this year. On March 25, Hans Jansen—another fake name—tried to push the various Unix systems to upgrade to the new version of XZ Utils.

And everyone was poised to do so. It’s a routine update. In the span of a few weeks, it would have been part of both Debian and Red Hat Linux, which run on the vast majority of servers on the Internet. But on March 29, another unpaid volunteer, Andres Freund—a real person who works for Microsoft but who was doing this in his spare time—noticed something weird about how much processing the new version of XZ Utils was doing. It’s the sort of thing that could be easily overlooked, and even more easily ignored. But for whatever reason, Freund tracked down the weirdness and discovered the backdoor.

It’s a masterful piece of work. It affects the SSH remote login protocol, basically by adding a hidden piece of functionality that requires a specific key to enable. Someone with that key can use the backdoored SSH to upload and execute an arbitrary piece of code on the target machine. SSH runs as root, so that code could have done anything. Let your imagination run wild.

This isn’t something a hacker just whips up. This backdoor is the result of a years-long engineering effort. The ways the code evades detection in source form, how it lies dormant and undetectable until activated, and its immense power and flexibility give credence to the widely held assumption that a major nation-state is behind this.

If it hadn’t been discovered, it probably would have eventually ended up on every computer and server on the Internet. Though it’s unclear whether the backdoor would have affected Windows and macOS, it would have worked on Linux. Remember in 2020, when Russia planted a backdoor into SolarWinds that affected 14,000 networks? That seemed like a lot, but this would have been orders of magnitude more damaging. And again, the catastrophe was averted only because a volunteer stumbled on it. And it was possible in the first place only because the first unpaid volunteer, someone who turned out to be a national security single point of failure, was personally targeted and exploited by a foreign actor.

This is no way to run critical national infrastructure. And yet, here we are. This was an attack on our software supply chain. This attack subverted software dependencies. The SolarWinds attack targeted the update process. Other attacks target system design, development, and deployment. Such attacks are becoming increasingly common and effective, and also are increasingly the weapon of choice of nation-states.

It’s impossible to count how many of these single points of failure are in our computer systems. And there’s no way to know how many of the unpaid and unappreciated maintainers of critical software libraries are vulnerable to pressure. (Again, don’t blame them. Blame the industry that is happy to exploit their unpaid labor.) Or how many more have accidentally created exploitable vulnerabilities. How many other coercion attempts are ongoing? A dozen? A hundred? It seems impossible that the XZ Utils operation was a unique instance.

Solutions are hard. Banning open source won’t work; it’s precisely because XZ Utils is open source that an engineer discovered the problem in time. Banning software libraries won’t work, either; modern software can’t function without them. For years, security engineers have been pushing something called a “software bill of materials”: an ingredients list of sorts so that when one of these packages is compromised, network owners at least know if they’re vulnerable. The industry hates this idea and has been fighting it for years, but perhaps the tide is turning.

The fundamental problem is that tech companies dislike spending extra money even more than programmers dislike doing extra work. If there’s free software out there, they are going to use it—and they’re not going to do much in-house security testing. Easier software development equals lower costs equals more profits. The market economy rewards this sort of insecurity.

We need some sustainable ways to fund open-source projects that become de facto critical infrastructure. Public shaming can help here. The Open Source Security Foundation (OSSF), founded in 2022 after another critical vulnerability in an open-source library—Log4j—was discovered, addresses this problem. The big tech companies pledged $30 million in funding after the critical Log4j supply chain vulnerability, but they never delivered. And they are still happy to make use of all this free labor and free resources, as a recent Microsoft anecdote indicates. The companies benefiting from these freely available libraries need to actually step up, and the government can force them to.

There’s a lot of tech that could be applied to this problem, if corporations were willing to spend the money. Liabilities will help. The Cybersecurity and Infrastructure Security Agency’s (CISA’s) “secure by design” initiative will help, and CISA is finally partnering with OSSF on this problem. Certainly the security of these libraries needs to be part of any broad government cybersecurity initiative.

We got extraordinarily lucky this time, but maybe we can learn from the catastrophe that didn’t happen. Like the power grid, communications network, and transportation systems, the software supply chain is critical infrastructure, part of national security, and vulnerable to foreign attack. The US government needs to recognize this as a national security problem and start treating it as such.

This essay originally appeared in Lawfare.

Posted on April 11, 2024 at 7:01 AM • View Comments

XZ Utils Backdoor

The cybersecurity world got really lucky last week. An intentionally placed backdoor in XZ Utils, an open-source compression utility, was pretty much accidentally discovered by a Microsoft engineer—weeks before it would have been incorporated into both Debian and Red Hat Linux. From ArsTehnica:

Malicious code added to XZ Utils versions 5.6.0 and 5.6.1 modified the way the software functions. The backdoor manipulated sshd, the executable file used to make remote SSH connections. Anyone in possession of a predetermined encryption key could stash any code of their choice in an SSH login certificate, upload it, and execute it on the backdoored device. No one has actually seen code uploaded, so it’s not known what code the attacker planned to run. In theory, the code could allow for just about anything, including stealing encryption keys or installing malware.

It was an incredibly complex backdoor. Installing it was a multi-year process that seems to have involved social engineering the lone unpaid engineer in charge of the utility. More from ArsTechnica:

In 2021, someone with the username JiaT75 made their first known commit to an open source project. In retrospect, the change to the libarchive project is suspicious, because it replaced the safe_fprint function with a variant that has long been recognized as less secure. No one noticed at the time.

The following year, JiaT75 submitted a patch over the XZ Utils mailing list, and, almost immediately, a never-before-seen participant named Jigar Kumar joined the discussion and argued that Lasse Collin, the longtime maintainer of XZ Utils, hadn’t been updating the software often or fast enough. Kumar, with the support of Dennis Ens and several other people who had never had a presence on the list, pressured Collin to bring on an additional developer to maintain the project.

There’s a lot more. The sophistication of both the exploit and the process to get it into the software project scream nation-state operation. It’s reminiscent of Solar Winds, although (1) it would have been much, much worse, and (2) we got really, really lucky.

I simply don’t believe this was the only attempt to slip a backdoor into a critical piece of Internet software, either closed source or open source. Given how lucky we were to detect this one, I believe this kind of operation has been successful in the past. We simply have to stop building our critical national infrastructure on top of random software libraries managed by lone unpaid distracted—or worse—individuals.

Posted on April 2, 2024 at 2:50 PM • View Comments

LLM Prompt Injection Worm

Researchers have demonstrated a worm that spreads through prompt injection. Details:

In one instance, the researchers, acting as attackers, wrote an email including the adversarial text prompt, which “poisons” the database of an email assistant using retrieval-augmented generation (RAG), a way for LLMs to pull in extra data from outside its system. When the email is retrieved by the RAG, in response to a user query, and is sent to GPT-4 or Gemini Pro to create an answer, it “jailbreaks the GenAI service” and ultimately steals data from the emails, Nassi says. “The generated response containing the sensitive user data later infects new hosts when it is used to reply to an email sent to a new client and then stored in the database of the new client,” Nassi says.

In the second method, the researchers say, an image with a malicious prompt embedded makes the email assistant forward the message on to others. “By encoding the self-replicating prompt into the image, any kind of image containing spam, abuse material, or even propaganda can be forwarded further to new clients after the initial email has been sent,” Nassi says.

It’s a natural extension of prompt injection. But it’s still neat to see it actually working.

Research paper: “ComPromptMized: Unleashing Zero-click Worms that Target GenAI-Powered Applications.

Abstract: In the past year, numerous companies have incorporated Generative AI (GenAI) capabilities into new and existing applications, forming interconnected Generative AI (GenAI) ecosystems consisting of semi/fully autonomous agents powered by GenAI services. While ongoing research highlighted risks associated with the GenAI layer of agents (e.g., dialog poisoning, membership inference, prompt leaking, jailbreaking), a critical question emerges: Can attackers develop malware to exploit the GenAI component of an agent and launch cyber-attacks on the entire GenAI ecosystem?

This paper introduces Morris II, the first worm designed to target GenAI ecosystems through the use of adversarial self-replicating prompts. The study demonstrates that attackers can insert such prompts into inputs that, when processed by GenAI models, prompt the model to replicate the input as output (replication), engaging in malicious activities (payload). Additionally, these inputs compel the agent to deliver them (propagate) to new agents by exploiting the connectivity within the GenAI ecosystem. We demonstrate the application of Morris II against GenAI-powered email assistants in two use cases (spamming and exfiltrating personal data), under two settings (black-box and white-box accesses), using two types of input data (text and images). The worm is tested against three different GenAI models (Gemini Pro, ChatGPT 4.0, and LLaVA), and various factors (e.g., propagation rate, replication, malicious activity) influencing the performance of the worm are evaluated.

Posted on March 4, 2024 at 7:01 AM • View Comments

PIN-Stealing Android Malware

This is an old piece of malware—the Chameleon Android banking Trojan—that now disables biometric authentication in order to steal the PIN:

The second notable new feature is the ability to interrupt biometric operations on the device, like fingerprint and face unlock, by using the Accessibility service to force a fallback to PIN or password authentication.

The malware captures any PINs and passwords the victim enters to unlock their device and can later use them to unlock the device at will to perform malicious activities hidden from view.

Posted on January 9, 2024 at 7:03 AM • View Comments

LitterDrifter USB Worm

A new worm that spreads via USB sticks is infecting computers in Ukraine and beyond.

The group­—known by many names, including Gamaredon, Primitive Bear, ACTINIUM, Armageddon, and Shuckworm—has been active since at least 2014 and has been attributed to Russia’s Federal Security Service by the Security Service of Ukraine. Most Kremlin-backed groups take pains to fly under the radar; Gamaredon doesn’t care to. Its espionage-motivated campaigns targeting large numbers of Ukrainian organizations are easy to detect and tie back to the Russian government. The campaigns typically revolve around malware that aims to obtain as much information from targets as possible.

One of those tools is a computer worm designed to spread from computer to computer through USB drives. Tracked by researchers from Check Point Research as LitterDrifter, the malware is written in the Visual Basic Scripting language. LitterDrifter serves two purposes: to promiscuously spread from USB drive to USB drive and to permanently infect the devices that connect to such drives with malware that permanently communicates with Gamaredon-operated command-and-control servers.

Posted on November 24, 2023 at 7:04 AM • View Comments

Security Vulnerability of Switzerland’s E-Voting System

Online voting is insecure, period. This doesn’t stop organizations and governments from using it. (And for low-stakes elections, it’s probably fine.) Switzerland—not low stakes—uses online voting for national elections. Andrew Appel explains why it’s a bad idea:

Last year, I published a 5-part series about Switzerland’s e-voting system. Like any internet voting system, it has inherent security vulnerabilities: if there are malicious insiders, they can corrupt the vote count; and if thousands of voters’ computers are hacked by malware, the malware can change votes as they are transmitted. Switzerland “solves” the problem of malicious insiders in their printing office by officially declaring that they won’t consider that threat model in their cybersecurity assessment.

But it also has an interesting new vulnerability:

The Swiss Post e-voting system aims to protect your vote against vote manipulation and interference. The goal is to achieve this even if your own computer is infected by undetected malware that manipulates a user vote. This protection is implemented by special return codes (Prüfcode), printed on the sheet of paper you receive by physical mail. Your computer doesn’t know these codes, so even if it’s infected by malware, it can’t successfully cheat you as long as, you follow the protocol.

Unfortunately, the protocol isn’t explained to you on the piece of paper you get by mail. It’s only explained to you online, when you visit the e-voting website. And of course, that’s part of the problem! If your computer is infected by malware, then it can already present to you a bogus website that instructs you to follow a different protocol, one that is cheatable. To demonstrate this, I built a proof-of-concept demonstration.

Appel again:

Kuster’s fake protocol is not exactly what I imagined; it’s better. He explains it all in his blog post. Basically, in his malware-manipulated website, instead of displaying the verification codes for the voter to compare with what’s on the paper, the website asks the voter to enter the verification codes into a web form. Since the website doesn’t know what’s on the paper, that web-form entry is just for show. Of course, Kuster did not employ a botnet virus to distribute his malware to real voters! He keeps it contained on his own system and demonstrates it in a video.

Again, the solution is paper. (Here I am saying that in 2004.) And, no, blockchain does not help—it makes security worse.

Posted on October 17, 2023 at 7:11 AM • View Comments

Operation Triangulation: Zero-Click iPhone Malware

Kaspersky is reporting a zero-click iOS exploit in the wild:

Mobile device backups contain a partial copy of the filesystem, including some of the user data and service databases. The timestamps of the files, folders and the database records allow to roughly reconstruct the events happening to the device. The mvt-ios utility produces a sorted timeline of events into a file called “timeline.csv,” similar to a super-timeline used by conventional digital forensic tools.

Using this timeline, we were able to identify specific artifacts that indicate the compromise. This allowed to move the research forward, and to reconstruct the general infection sequence:

  • The target iOS device receives a message via the iMessage service, with an attachment containing an exploit.
  • Without any user interaction, the message triggers a vulnerability that leads to code execution.
  • The code within the exploit downloads several subsequent stages from the C&C server, that include additional exploits for privilege escalation.
  • After successful exploitation, a final payload is downloaded from the C&C server, that is a fully-featured APT platform.
  • The initial message and the exploit in the attachment is deleted

The malicious toolset does not support persistence, most likely due to the limitations of the OS. The timelines of multiple devices indicate that they may be reinfected after rebooting. The oldest traces of infection that we discovered happened in 2019. As of the time of writing in June 2023, the attack is ongoing, and the most recent version of the devices successfully targeted is iOS 15.7.

No attribution as of yet.

Posted on June 9, 2023 at 7:12 AM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.