Les grands modèles de langage (LLM), comme le célèbre GPT-4 d’OpenAI, font des prouesses en termes de génération de texte, de code et de résolution de problèmes. Perso, je ne peux plus m’en passer, surtout quand je code. Mais ces avancées spectaculaires de l’IA pourraient avoir un côté obscur : la capacité à exploiter des vulnérabilités critiques.

C’est ce que révèle une étude de chercheurs de l’Université d’Illinois à Urbana-Champaign, qui ont collecté un ensemble de 15 vulnérabilités 0day bien réelles, certaines classées comme critiques dans la base de données CVE et le constat est sans appel. Lorsqu’on lui fournit la description CVE, GPT-4 parvient à concevoir des attaques fonctionnelles pour 87% de ces failles ! En comparaison, GPT-3.5, les modèles open source (OpenHermes-2.5-Mistral-7B, Llama-2 Chat…) et même les scanners de vulnérabilités comme ZAP ou Metasploit échouent lamentablement avec un taux de 0%.

Heureusement, sans la description CVE, les performances de GPT-4 chutent à 7% de réussite. Il est donc bien meilleur pour exploiter des failles connues que pour les débusquer lui-même. Ouf !

Mais quand même, ça fait froid dans le dos… Imaginez ce qu’on pourrait faire avec un agent IA qui serait capable de se balader sur la toile pour mener des attaques complexes de manière autonome. Accès root à des serveurs, exécution de code arbitraire à distance, exfiltration de données confidentielles… Tout devient possible et à portée de n’importe quel script kiddie un peu motivé.

Et le pire, c’est que c’est déjà rentable puisque les chercheurs estiment qu’utiliser un agent LLM pour exploiter des failles coûterait 2,8 fois moins cher que de la main-d’œuvre cyber-criminelle. Sans parler de la scalabilité de ce type d’attaques par rapport à des humains qui ont des limites.

Alors concrètement, qu’est ce qu’on peut faire contre ça ? Et bien, rien de nouveau, c’est comme d’hab, à savoir :

• Patcher encore plus vite les vulnérabilités critiques, en priorité les « 0day » qui menacent les systèmes en prod
• Monitorer en continu l’émergence de nouvelles vulnérabilités et signatures d’attaques
• Mettre en place des mécanismes de détection et réponse aux incidents basés sur l’IA pour contrer le feu par le feu
• Sensibiliser les utilisateurs aux risques et aux bonnes pratiques de « cyber-hygiène »
• Repenser l’architecture de sécurité en adoptant une approche « zero trust » et en segmentant au maximum
• Investir dans la recherche et le développement en cybersécurité pour garder un coup d’avance

Les fournisseurs de LLM comme OpenAI ont aussi un rôle à jouer en mettant en place des garde-fous et des mécanismes de contrôle stricts sur leurs modèles. La bonne nouvelle, c’est que les auteurs de l’étude les ont avertis et ces derniers ont demandé de ne pas rendre publics les prompts utilisés dans l’étude, au moins le temps qu’ils « corrigent » leur IA.

Source

Read 33 remaining paragraphs | Comments

Si vous me lisez assidument, vous avez surement tout capté à la fameuse backdoor XZ découverte avec fracas la semaine dernière. Et là je viens de tomber sur un truc « rigolo » qui n’est ni plus ni moins qu’une implémentation de la technique d’exploitation de cette backdoor XZ, directement à l’intérieur d’un agent SSH.

Pour rappel, un agent SSH (comme ssh-agent) est un programme qui tourne en arrière-plan et qui garde en mémoire les clés privées déchiffrées durant votre session. Son rôle est donc de fournir ces clés aux clients SSH quand ils en ont besoin pour s’authentifier, sans que vous ayez à retaper votre phrase de passe à chaque fois.

Cet agent démoniaque s’appelle donc JiaTansSSHAgent , en hommage au cybercriminel qui a vérolé XZ, et ça implémente certaines fonctionnalités de la fameuse backdoor sshd XZ. En clair, ça vous permet de passer par cette backdoor en utilisant votre client SSH préféré.

Ce truc va donc d’abord générer sa propre clé privée ed448 avec OpenSSL puis, il faudra patcher la liblzma.so avec la clé publique ed448 correspondante. Là encore, rien de bien méchant, c’est juste un petit script Python et enfin, dernière étape, faudra patcher votre client SSH pour qu’il ignore la vérification du certificat.

Et voilà !

Une fois que vous avez fait tout ça, vous pouvez vous connecter à cœur joie avec n’importe quel mot de passe sur n’importe quel serveur qui dispose de cette faille. Bon après, faut quand même faire gaffe hein, c’est pas un truc à utiliser n’importe comment non plus. Vous devez respecter la loi , et expérimenter cela uniquement sur votre propre matériel ou avec l’autorisation de votre client si vous êtes par exemple dans le cadre d’une mission d’audit de sécurité. Tout autre utilisation vous enverra illico en prison, alors déconnez pas !

Voilà les amis, vous savez tout sur JiaTansSSHAgent maintenant. Pour en savoir plus, rendez-vous sur le repo GitHub de JiaTanSSHAgent .

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 Mac, 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 turns 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 U.S. government needs to recognize this as a national security problem and start treating it as such.

This essay originally appeared in Lawfare .

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.

Enlarge (credit: Getty Images)

As many as 91,000 LG TVs face the risk of being commandeered unless they receive a just-released security update patching four critical vulnerabilities discovered late last year.

The vulnerabilities are found in four LG TV models that collectively comprise slightly more than 88,000 units around the world, according to results returned by the Shodan search engine for Internet-connected devices. The vast majority of those units are located in South Korea, followed by Hong Kong, the US, Sweden, and Finland. The models are:

• LG43UM7000PLA running webOS 4.9.7 - 5.30.40
• OLED55CXPUA running webOS 5.5.0 - 04.50.51
• OLED48C1PUB running webOS 6.3.3-442 (kisscurl-kinglake) - 03.36.50
• OLED55A23LA running webOS 7.3.1-43 (mullet-mebin) - 03.33.85

Starting Wednesday, updates are available through these devices’ settings menu.

Read 9 remaining paragraphs | Comments

In discovering malicious code that endangered global networks in open-source software, Andres Freund exposed our reliance on insecure, volunteer-maintained tech

On Good Friday, a Microsoft engineer named Andres Freund noticed something peculiar. He was using a software tool called SSH for securely logging into remote computers on the internet, but the interactions with the distant machines were significantly slower than usual. So he did some digging and found malicious code embedded in a software package called XZ Utils that was running on his machine. This is a critical utility for compressing (and decompressing) data running on the Linux operating system, the OS that powers the vast majority of publicly accessible internet servers across the world. Which means that every such machine is running XZ Utils.

Freund’s digging revealed that the malicious code had arrived in his machine via two recent updates to XZ Utils, and he alerted the Open Source Security list to reveal that those updates were the result of someone intentionally planting a backdoor in the compression software. It was what is called a “supply-chain attack” (like the catastrophic SolarWinds one of 2020 ) – where malicious software is not directly injected into targeted machines, but distributed by infecting the regular software updates to which all computer users are wearily accustomed. If you want to get malware out there, infecting the supply chain is the smart way to do it.

Beijing did a test run in Taiwan using AI-generated content to influence voters away from a pro-sovereignty candidate

China will attempt to disrupt elections in the US, South Korea and India this year with artificial intelligence-generated content after making a dry run with the presidential poll in Taiwan, Microsoft has warned.

The US tech firm said it expected Chinese state-backed cyber groups to target high-profile elections in 2024, with North Korea also involved, according to a report by the company’s threat intelligence team published on Friday.

Enlarge / Three examples of the video screen tampering. (credit: US DOJ)

Was someone messing with the Jacksonville Jaguars' giant jumbotron ?

On September 16, 2018, the Jaguars were playing the New England Patriots when the in-stadium screen experienced, in the US government's words, "a loss in reference sync which manifested as a large horizontal green lines [sic] appearing across one whole video board."

On November 18, during a game against the Pittsburgh Steelers, it happened again—but this time, entire video sub-boards filled with green.

Read 25 remaining paragraphs | Comments