linux | Breaking Cybersecurity News | The Hacker News

A Chinese threat actor tracked as UAT-7810 is actively refining its bespoke malware to expand its Operational Relay Box (ORB) network by breaking into internet-facing networking devices. According to findings from Cisco Talos, UAT-7810 is an advanced persistent threat (APT) actor that's responsible for maintaining and proliferating LapDogs , an ORB network that first came to light in June 2025. "UAT-7810 is most likely tasked with establishing Operational Relay Box (ORB) networks that can then be leveraged by associated secondary threat actors to conduct their own malicious attacks against high value targets," researchers Jungsoo An, Asheer Malhotra, Vanja Svajcer, and Brandon White said . One such China-nexus threat actor that has leveraged the infrastructure in its own attacks is UAT-5918 , which has been linked to cyber attacks targeting critical infrastructure entities in Taiwan since at least 2023 with an aim to establish persistent access within victim envir...

Researchers at  Nebula Security  have disclosed GhostLock ( CVE-2026-43499 ), a 15-year-old Linux kernel flaw that lets any logged-in user take full root control of a machine that has not been patched. The vulnerable code has shipped by default in essentially every mainstream distribution since 2011. The flaw needs no special permission, no unusual settings, and no network access; ordinary threading calls from any local program are enough. Nebula turned it into a working root exploit that is 97% reliable in its testing and also escapes containers, and says Google awarded the team $92,337 through its  kernelCTF  bug-bounty program. No one is known to be exploiting it in the wild, but Nebula has published  working exploit code , so anyone can now run it. Patching is the priority. How the bug works The kernel has a system for keeping an urgent task from getting stuck behind a trivial one. Part of it is a cleanup step that tidies up after a task...

A use-after-free bug in Linux's KVM hypervisor can be triggered from a guest virtual machine to corrupt the shadow-page state of the host kernel that runs it. Dubbed ' Januscape ' and tracked as  CVE-2026-53359 , the flaw sits in the shadow MMU code that KVM shares across both Intel and AMD. The public proof-of-concept panics the host; the researcher claims that a separate, unreleased exploit turns the same bug into full host code execution. Security researcher  Hyunwoo Kim (@v4bel) found and reported the bug. He described Januscape as the first guest-to-host exploit triggerable on both Intel and AMD, to the best of public knowledge. The flaw went unnoticed for roughly 16 years. According to Kim, the exploit was used as a zero-day submission in  Google's kvmCTF , the controlled KVM vulnerability reward program that offers up to $250,000 for full guest-to-host escapes. How It Works To run a virtual machine, KVM keeps its own private set of page tables that mi...

Cybersecurity researchers have flagged a novel Java-based remote access trojan (RAT) called QuimaRAT that's capable of targeting Windows, Linux, and macOS environments. According to LevelBlue, the cross-platform malware is advertised under a malware-as-a-service (MaaS) model, costing anywhere between $150 for one month to $1,200 for lifetime access. Other subscription tiers include $300 for three months, $500 for six months, and $700 for twelve months. "Built around a modular architecture, the RAT supports dynamic capability expansion through encrypted plugins that can be delivered, loaded, unloaded, and updated directly from its command-and-control (C2) infrastructure," the cybersecurity company said in an analysis of the malware. The malware author also advertises a builder capable of generating multiple output formats, including JAR, EXE, APP, SH, BAT, and VBS, indicating an attempt to help prospective customers package the client tailored for different enviro...

A newly disclosed Linux kernel flaw called Bad Epoll (CVE-2026-46242) lets an ordinary user with no special access take full control of a machine as root. It affects Linux desktops, servers, and Android, and a fix is out. Bad Epoll sits in the same small stretch of kernel code where Anthropic's most powerful AI model, Mythos , recently found a different bug. The AI caught one flaw and missed this one. A researcher, Jaeyoung Chung, found it and built a working attack. How the Bug Works Epoll is a standard Linux feature that lets a program watch many files or network connections at once. Servers, network services, and web browsers all lean on it. You cannot simply switch it off. Bad Epoll is a "use-after-free" bug. Two parts of the kernel try to clean up the same internal object at the same time. One frees the memory while the other is still writing into it. That brief collision lets an attacker corrupt kernel memory, then climb from a normal account up to root...

DirtyClone is a new Linux kernel privilege escalation in the DirtyFrag family. JFrog Security Research published a working exploit walkthrough for the flaw on June 25, the first public demonstration for this variant. Tracked as  CVE-2026-43503  (CVSS 8.8), it lets a local user corrupt file-backed memory through a cloned network packet and gain root. The patch landed in mainline on May 21; if your kernel does not have it, update now. When the kernel copies a network packet internally, two helper functions drop a safety flag that marks the packet's memory as shared with a file on disk. That missing flag is the entire vulnerability. The attacker loads a privileged binary like /usr/bin/su into memory, wires those memory pages into a network packet, and forces the kernel to clone it. The cloned packet passes through an IPsec tunnel that the attacker controls, and the decryption step overwrites the binary's login checks with attacker-chosen bytes. The next time anyo...

Cybersecurity researchers have flagged two previously undocumented Windows variants of what was believed to be a Linux-only backdoor called SprySOCKS . "The Windows variants discovered are internally marked as WIN_DRV and WIN_PLUS," ESET said in a report shared with The Hacker News. "Both come with a hard-coded C&C [command-and-control] configuration and support communication over TCP, UDP, and WebSocket protocols." Like its Linux counterpart, the Windows versions support more than 30 commands to facilitate system information collection, process enumeration, service management, and file system operations. WIN_DRV has also been found to utilize kernel drivers to conceal the malware's network connections, processes, files, and registry keys. In addition, the variant enables TCP traffic diversion that allows the malware operators to send commands to the backdoor through a random TCP port on the victim's device without exposing the backdoor's act...

Instead of hiding on the laptops and servers defenders watch most closely, a China-nexus group spent close to a decade hidden inside the Linux login system itself. Sygnia, which tracks the group as Velvet Ant , says it backdoored the PAM and OpenSSH components that decide who is allowed to sign in, planting its access where ordinary cleanup could not reach it. The network it targeted had no direct internet access, so the group first staged through internet-facing systems to get there. The earliest traces go back to 2016. Instead of dropping new malware that a scanner might catch, the attacker changed the trusted login programs themselves. Nothing obvious appeared, and no exploit was needed, so the activity looked like normal administration. On many machines, the attacker replaced the main PAM login module with backdoored copies. Some let them in with a secret password; others quietly recorded real usernames and passwords as people logged in. Researchers found nine separate ver...

A malicious website can work out which sites you visit and which apps you open, using nothing but JavaScript and the timing of your SSD. The attack, called FROST , needs no native code, no extension, and no permission prompt. You open the page, leave the tab sitting there, and it watches the drive for contention in the background. Researchers at Graz University of Technology built it and described it in a new paper set to appear at DIMVA 2026. It abuses a storage feature present in every major desktop browser, and the underlying timing channel works on both macOS and Linux. SSD timing attacks are not new. Last year the same group published Secret Spilling Drive , which read user behavior off a drive by watching how reads slow down when something else is using it. The catch was that it needed native code on the machine, through a low-level interface like Linux's io_uring. FROST drops that requirement. It runs inside the browser sandbox, which turns a local attack into a remo...

Security researchers have published a detailed, working exploit for a Linux kernel use-after-free that lets an unprivileged local user escalate to root and break out of a container. The flaw, CVE-2026-23111, sits in the kernel's nf_tables packet-filtering code and was patched upstream on February 5, 2026. Exodus Intelligence released its full technical walkthrough on June 8, and it is not even the first public exploit: FuzzingLabs published an independent reproduction back in April. The flaw came down to a single stray character, an inverted check in nf_tables, and the upstream fix removed it in one line. Ubuntu rates the flaw CVSS 7.8 (high). If your distribution's kernel package does not yet include the fix, update and reboot. The reachable setup is common: nf_tables plus unprivileged user namespaces, a Linux feature that lets an ordinary account act as root inside a private sandbox and reach kernel code it otherwise could not. Both ship by default on most desktop...

A China-nexus cyber espionage group has been observed deploying a BSD variant of a known backdoor called BRICKSTORM, as well as two other malware families codenamed PLENET (aka GRIMBOLT ) and AGENTPSD to target Linux systems. The activity has been attributed by Volexity to a threat cluster it tracks as VerdantBamboo , which it said overlaps with hacking groups known as Clay Typhoon (Microsoft), UNC5221 (Google), and Warp Panda (CrowdStrike). The cybersecurity company said it discovered the intrusion during an incident response engagement in September 2025, when it emerged that the adversary had compromised an unnamed victim's Egnyte Storage Sync system by exploiting a local privilege escalation flaw to deploy BRICKSTORM. The issue was addressed in Storage Sync version 13.13 , released in March 2026.

A new "coordinated" supply chain attack campaign has impacted eight packages on Packagist including malicious code designed to run a Linux binary retrieved from a GitHub Releases URL. "Although the affected packages were all Composer packages, the malicious code was not added to composer.json," Socket said . "Instead, it was inserted into package.json, targeting projects that ship JavaScript build tooling alongside PHP code." This "cross-ecosystem placement" makes the activity stand out because developers and security teams scanning PHP dependencies may only focus on Composer-related metadata, while skipping package.json lifecycle hooks that are bundled within the package. The malicious versions have since been removed from Packagist. An analysis of the packages has uncovered that their upstream repositories have been modified to include a postinstall script that attempts to download a Linux binary from a GitHub Releases URL ("github[...

Cybersecurity researchers have disclosed details of a new Linux malware dubbed Showboat that has been put to use in a campaign targeting a telecommunications provider in the Middle East since at least mid-2022. "Showboat is a modular post-exploitation framework designed for Linux systems, capable of spawning a remote shell, transferring files, and functioning as a SOCKS5 proxy," Lumen Technologies Black Lotus Labs said in a report shared with The Hacker News. It's assessed that the malware has been employed by at least one, and possibly more, threat activity clusters affiliated with China, with correlations identified between command-and-control (C2) nodes and IP addresses geolocated to Chengdu, the capital city of the Chinese province of Sichuan. One such threat actor is Calypso (aka Bronze Medley and Red Lamassu), which is known to be active since at least September 2016, targeting state institutions in Brazil, India, Kazakhstan, Russia, Thailand, and Turkey. ...

Cybersecurity researchers have disclosed details of a vulnerability in the Linux kernel that remained undetected for nine years. The vulnerability, tracked as CVE-2026-46333 (CVSS score: 5.5), is a case of improper privilege management that could permit an unprivileged local user to disclose sensitive files and execute arbitrary commands as root on default installations of several major distributions like Debian, Fedora, and Ubuntu. It's also codenamed ssh-keysign-pwn. According to Qualys, which discovered the flaw, the problem is rooted in the kernel's __ptrace_may_access() function and was introduced in November 2016. "The primitive is reliable and turns any local shell into a path to root or to sensitive credential material," Saeed Abbasi, senior manager of Threat Research Unit at Qualys, said . Successful exploitation of the flaw could permit a local attacker to disclose /etc/shadow and host private keys under /etc/ssh/*_key, as well as execute arbitrary...

Proof-of-concept (PoC) exploit code has now been released for a recently patched security flaw in the Linux kernel that could allow for local privilege escalation (LPE). Dubbed DirtyDecrypt (aka DirtyCBC), the vulnerability was discovered and reported by the Zellic and V12 security team on May 9, 2026, only to be informed by the maintainers that it was a duplicate of a vulnerability that had already been patched in the mainline. "It's a rxgk pagecache write due to missing COW [copy-on-write] guard in rxgk_decrypt_skb," Zellic co-founder Luna Tong (aka cts and gf_256) said in a description shared on GitHub. Although the CVE identifier was not disclosed, the vulnerability in question is CVE-2026-31635 (CVSS score: 7.5) based on the fact that the NIST National Vulnerability Database (NVD) includes a link to the DirtyDecrypt PoC in its CVE record. "The specific fault sits in rxgk_decrypt_skb(), the function that decrypts an incoming sk_buff (socket buffer) on th...

Details have emerged about a new variant of the recent Dirty Frag Linux local privilege escalation (LPE) vulnerability that allows local attackers to gain root access, making it the third such bug to be identified in the kernel within a span of two weeks. Codenamed Fragnesia , the security vulnerability is tracked as CVE-2026-46300 (CVSS score: 7.8) and is rooted in the Linux kernel's XFRM ESP-in-TCP subsystem. It was discovered by researcher William Bowling of Zellic and the V12 security team. "The vulnerability allows unprivileged local attackers to modify read-only file contents in the kernel page cache and achieve root privileges through a deterministic page-cache corruption primitive," Google-owned Wiz said . Advisories have been released by multiple Linux distributions - AlmaLinux Amazon Linux CloudLinux Debian Gentoo Red Hat Enterprise Linux SUSE Ubuntu "This is a separate bug in the ESP/XFRM from Dirty Frag which has received its own patch,...

A previously undocumented Linux implant codenamed Quasar Linux RAT (QLNX) is targeting developers' systems to establish a silent foothold as well as facilitate a broad range of post-compromise functionality, such as credential harvesting, keylogging, file manipulation, clipboard monitoring, and network tunneling. "QLNX targets developers and DevOps credentials across the software supply chain," Trend Micro researchers Aliakbar Zahravi and Ahmed Mohamed Ibrahim said in a technical analysis of the malware. "Its credential harvester extracts secrets from high-value files such as .npmrc (npm tokens), .pypirc (PyPI credentials), .git-credentials, .aws/credentials, .kube/config, .docker/config.json, .vault-token, Terraform credentials, GitHub CLI tokens, and .env files. The compromise of these assets could allow the operator to push malicious packages to NPM or PyPI registries, access cloud infrastructure, or pivot through CI/CD pipelines." The malware's ab...

Cybersecurity researchers have disclosed details of a new Linux backdoor named PamDOORa that's being advertised on the Rehub Russian cybercrime forum for $1,600 by a threat actor called "darkworm." The backdoor is designed as a Pluggable Authentication Module ( PAM )-based post-exploitation toolkit that enables persistent SSH access by means of a magic password and specific TCP port combination. It's also capable of harvesting credentials from all legitimate users who authenticate through the compromised system. "The tool, called PamDOORa, is a new PAM-based backdoor, designed to serve as a post-exploitation backdoor, enabling authentication to servers via OpenSSH," Flare.io researcher Assaf Morag said in a technical report. "Allegedly this would remain persistent on Linux systems (x86_64)." PamDOORa is the second Linux backdoor after Plague to be discovered targeting the PAM stack over the past year. PAM is a security framework in Unix/Linu...

Details have emerged about a new, unpatched local privilege escalation (LPE) vulnerability impacting the Linux kernel. Dubbed Dirty Frag , it has been described as a successor to Copy Fail (CVE-2026-31431, CVSS score: 7.8), a recently disclosed LPE flaw impacting the Linux kernel that has since come under active exploitation in the wild. The vulnerability was reported to Linux kernel maintainers on April 30, 2026. "Dirty Frag is a vulnerability (class) that achieves root privileges on most Linux distributions by chaining the xfrm-ESP Page-Cache Write vulnerability and the RxRPC Page-Cache Write vulnerability," security researcher Hyunwoo Kim (@v4bel) said in a write-up. "Dirty Frag is a case that extends the bug class to which Dirty Pipe and Copy Fail belong. Because it is a deterministic logic bug that does not depend on a timing window, no race condition is required, the kernel does not panic when the exploit fails, and the success rate is very high." T...

Cybersecurity researchers have discovered three packages on the Python Package Index (PyPI) repository that are designed to stealthily deliver a previously unknown malware family called  ZiChatBot on Windows and Linux systems. "While these wheel packages do implement the features described on their PyPI web pages, their true purpose is to covertly deliver malicious files," Kaspersky  said . "Unlike traditional malware, ZiChatBot does not communicate with a dedicated command-and-control (C2) server, but instead uses a series of REST APIs from the public team chat app Zulip as its C2 infrastructure." The activity has been described as a "carefully planned and executed PyPI supply chain attack" by the Russian cybersecurity company. The names of the packages, which have since been taken down, are listed below - uuid32-utils (1,479 downloads) colorinal (614 downloads) termncolor (387 downloads) All three packages were uploaded to PyPI during a short wi...