Security Hacks

1572 Articles

After Stumbling From CVE To CVE Will Linux Get A Kill Switch?

May 16, 2026 by 24 Comments

For the few people who have spent the past weeks living under a security rock, the Linux kernel has found itself the subject of multiple severe bugs in the form of Copy Fail and Dirty Frag, both of which allow for privilege escalation. They’ve made many people very upset, and also potentially put many thousands of systems at risk of exploitation. Worse is that system managers are generally left to twiddle their thumbs while waiting for patches to be rolled out. This is where NVIDIA engineer [Sasha Levin] has proposed a ‘kill switch’ for affected kernel functions.

The basic concept seems rather simple, with this feature merely intercepting a call to the affected function and instead returning a predefined return value. This makes it less extreme than hitting a general SCRAM button on the entire kernel, and could theoretically allow the affected systems to keep running until the patched kernel becomes available.

A disadvantage of this is that it obviously modifies the kernel, patching it in-memory so that you need to reboot the system to clear it. Another potential disadvantage is that it opens a potentially massive attack vector, with people in the Cybersecurity sub-Reddit roundly rejecting the idea. Amidst all the other anxious conversions there is also the concern that this particular patch was at least partially generated by an LLM (Claude Opus 4.7) , so one may hope that if it does gets merged into mainline it’ll at least be properly vetted by multiple pairs of well-caffeinated human eyes.

This Week In Security: Another Linux Exploit, Ubuntu Knocked Offline, Finals Interrupted, And Backdoored Tools

May 8, 2026 by 15 Comments

After the CopyFail vulnerability gave root access from any user on almost all distributions last week, this week we’ve got DirtyFrag. This chains the vulnerability in CopyFail (xfrm-ESP) and a new vulnerability in a RPC function which allows similar overwriting of the page cache.

Both vulnerabilities manipulate the Linux page cache where data from disk is stored for rapid access. The kernel will always prefer the cached version of a file, which means that anything that is able to manipulate the contents of the cache can effectively replace the contents of the file. Both of the vulnerabilities leverage a similar mechanism – picking a binary which is flagged to run as root, such as su, and replacing the contents that would prompt for the users password with a launcher to immediately run a shell.

Like CopyFail, DirtyFrag requires the ability to execute code on the target in the first place, but turning almost any code or command execution vulnerability in any network service into root raises the impact significantly, allowing an attacker to break out of containers and privilege environments, or establish a persistent presence in the system when the original vulnerabilities are discovered and closed.

The previous mitigations to block specific kernel modules related to CopyFail are not sufficient to block the new vulnerabilities. At the time of writing this, there are no available patches from the distributions, however the vulnerable kernel modules can be temporarily disabled.

CopyFail added to KEV

CISA (the United States cyber security agency) has added CopyFail to the KEV, or Known Exploited Vulnerabilities list. Attacks on the KEV have been observed under active exploitation, which in the case of CopyFail is hardly a surprise.

The KEV is designed as a tool to allow security teams in government and commercial industry to prioritize the highest risk vulnerabilities – or at least give another source of data to point at when you say “we really need to patch this now”.

Prolonged Ubuntu DDOS

On the heels of the CopyFail vulnerability impacting almost all distributions, Ubuntu has had to face a prolonged distributed denial-of-service (DDoS) attack against the main infrastructure. Ars Technica reported at the beginning of the attack, and after several days, services appear to be restored. In the meantime, core services such as package updates, core repositories, and even the Ubuntu and Canonical websites were largely unreachable.

An Iraqi group claims responsibility for the attack, but it is unclear if they were the actual perpetrators – or why. The timing with the CopyFail vulnerability seems like an opportune moment to cause chaos by taking the update mechanisms of a major distribution offline, but in the era of modern Internet behavior, it could also just have been a Tuesday.

Continue reading “This Week In Security: Another Linux Exploit, Ubuntu Knocked Offline, Finals Interrupted, And Backdoored Tools” →

This Week In Security: State Malware, State Hardware Bans, And Stuxnet Before Stuxnet Was Cool

May 1, 2026 by 8 Comments

Making headlines everywhere is the CopyFail Linux kernel vulnerability, which allows local privilege escalation (LPE) from any user to root privileges on most kernels and distributions.

Local privileges escalations are never good, but typically are not “Internet-melters”: they are significantly less dangerous than remote vulnerabilities, but are often combined with a remote vulnerability to gain complete access to a system.

This time, the vulnerability is in the Linux kernel handling of cryptographic functions used in IPSec. The mistake allows writing into the in-memory cache of file data; this allows modifying what the system thinks a file contains, without ever touching the contents of the actual file. Coupled with a suid binary — a binary configured to always run as root, no matter what user starts it — the binary can be modified to run any code as root. In this case, that means launching a new interactive shell. Nearly every distribution includes several standard suid binaries, such as the command su which requires root privileges to switch users.

The bug is pervasive, impacting kernels from 2017, and can be triggered on any distribution where the IPSec kernel modules are enabled and loaded, which is the vast majority of them. Kernel patches are available, and most distributions should have them at this point. For the average home user, you’ll want to upgrade as soon as is practical; for services with untrusted users or containerized systems which might run untrusted workloads, if updating immediately is not practical, Theori has mitigation suggestions on the blog post. Continue reading “This Week In Security: State Malware, State Hardware Bans, And Stuxnet Before Stuxnet Was Cool” →

This Week In Security: Annoyed Researchers, Dangling DNS, And Hacks That Could Have Been Worse

April 24, 2026 by 13 Comments

The author of the BlueHammer exploit, which was released earlier this month and addressed in the last Patch Tuesday, continues to be annoyed with the responses from the Microsoft security research and vulnerability response team, and has released another Windows zero-day attack against Windows Defender.

The RedSun exploit targets a logic and timing error in Windows Defender, convincing it to install the target file in the system, instead of quarantining the file and protecting the system. Not, generally, what you would hope would happen.

Since the RedSun attack requires local access in the first place, it seems unlikely Microsoft will release an out-of-sequence patch for it, however with public code available, we can probably expect to see malware leveraging it to establish higher permissions on an infected system.

Releasing exploits out of spite feels like a return to the late 1990s, and I almost don’t hate it.

University Domains Hijacked

Reported in Bleeping Computer, a group tracked as “Hazy Hawk” has been hijacking unmaintained DNS records of universities and government institutions to serve ad click spam.

The attack seems simple and doesn’t even require compromising the actual institution, using dangling DNS “CNAME” records. A “CNAME” entry in DNS acts essentially as an alias, pointing one domain name at another, which can be used to provide content from an official domain that is hosted on a cloud service where the IP address of the service might change.

A DNS “A” (or “AAAA” if you speak IPv6) record points a hostname – like “foo.example.com” – to an IP address – like “1.1.1.1”. A “CNAME” record points a hostname to another hostname, like “foo.some_cloud_host.com”. Scanning “high value” domains (like Ivy League universities) for “CNAME” records which point to expired domains (or domains on cloud hosted providers which no longer exist) lets anyone able to register that domain (or create an account with the proper naming scheme on the cloud host) to post any content they wish, and still appear to be the original name.

At least 30 educational institutions have been impacted, along with several government agencies including the CDC.

Continue reading “This Week In Security: Annoyed Researchers, Dangling DNS, And Hacks That Could Have Been Worse” →

How Anthropic’s Model Context Protocol Allows For Easy Remote Execution

April 24, 2026 by 32 Comments

As part of the effort to push Large Language Model (LLM) ‘AI’ into more and more places, Anthropic’s Model Context Protocol (MCP) has been adopted as the standard to connect LLMs with various external tools and systems in a client-server model. A light oversight with the architecture of this protocol is that remote command execution (RCE) of arbitrary commands is effectively an essential part of its design, as covered in a recent article by [OX Security].

The details of this flaw are found in a detailed breakdown article, which applies to all implementations regardless of the programming language. Essentially the StdioServerParameters that are passed to the remote server to create a new local instance on said server can contain any command and arguments, which are executed in a server-side shell.

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Encrypting Encrypted Traffic To Get Around VPN Bans

April 23, 2026 by 31 Comments

VPNs, Virtual Private Networks, aren’t just a good idea to keep your data secure: for millions of people living under restrictive regimes they’re the only way to ensure full access to the internet. What do you do when your government orders ISPs to ban VPNs, like Russia has done recently?  [LaserHelix] shows us one way you can cope, which is to use a ShadowSocks proxy.

If you’re not deep into network traffic, you might be wondering: how can an ISP block VPN traffic? Isn’t that stuff encrypted? Yes, but while the traffic going over the VPN is encrypted, you still need to connect to your VPN’s servers– and those handshake packets are easy enough to detect. You can do it at home with Wireshark, a tool that shows up fairly often on these pages. Of course if they can ID those packets, they can block them.

So, you just need a way to obfuscate what exactly the encrypted traffic you’re sending is. Luckily that’s a solved problem: Chinese hackers came up with something called Shadowsocks back in 2012 to help get around the Great Firewall, and have been in an arms-race with their authorities ever since.

Shadowsocks is not, in fact, a sibling of Gandalf’s horse as the name might suggest, but a tool to obfuscate the traffic going to your VPN. To invert a meme, you’re telling the authorities: we heard you don’t like encrypted traffic, so we put encryption in your encrypted traffic so you have to decrypt the packets before you recognize the encrypted packets.

What about the VPN? Well, some run their own shadowsocks service, while others will need to be accessed via a shadowsocks bridge: in effect, a proxy that then connects to the VPN for you. That means of course you’re bouncing through two servers you need to trust not to glow in the dark, but if you have to trust someone– otherwise it’s off to a shack in the woods, which never ends well.

Don’t forget that while VPNs can get you around government censorship, they do not provide anonymity on their own. If, like tipster [Keith Olson] –thanks for the tip, [Keith]!– you’re looking side-eyed at your government’s “think of the children!” rhetoric but don’t know where to start, we had a discussion about which VPNs to use last year.

This Week In Security: Docker Auth, Windows Tools, And A Very Full Patch Tuesday

April 17, 2026 by 5 Comments

CVE-2026-34040 lets attackers bypass some Docker authentication plugins by allowing an empty request body. Present since 2024, this bug was caused by a previous fix to the auth workflow. In the 2024 bug, the authentication system could be tricked into passing a zero-length request to the authentication handler. In the modern vulnerability, the system can be tricked into removing a too-large authentication request and passing a zero-length request to the authentication handler.

In both cases, the authentication system may not properly handle the malformed request and allow creation of docker images with access to stored credentials and secrets.

Bugs like these are increasing in visibility because AI agents running in Docker, like OpenClaw, may be tricked via prompt injection into leveraging the vulnerability.

Windows CPU Tools Compromised

videocardz.com notes that the popular Windows monitoring software Cpu-Z and HWMonitor appear to have been compromised. Reports indicate that the download site was compromised, not the actual packages, but that it was redirecting update requests to packages including malware. While the site has been repaired, unfortunately it looks like there is no warning to users that the downloads were compromised for a period of time.

Anecdotally, there has been a rash of Discord account takeovers in the past week, where long-standing accounts in multiple servers have been compromised and turned into spambots. While there is no evidence these events are linked, clearly a new credential or authentication stealing malware is in play, which involves stealing credentials from Discord.

X.Org and XWayland Updated

The X.Org and XWayland servers saw security updates this week, fixing a handful of vulnerabilities involving uninitialized memory use, use-after-free, and reading beyond the end of a buffer.

The vulnerabilities are generally classified as “moderate”, but of course, don’t leave known vulnerabilities when you can avoid it! Fixed releases should find their way into distributions soon.

Continue reading “This Week In Security: Docker Auth, Windows Tools, And A Very Full Patch Tuesday” →