linux | Breaking Cybersecurity News | The Hacker News

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...

The Apache Software Foundation (ASF) has released security updates to address several security vulnerabilities in the HTTP Server, including a severe vulnerability that could potentially lead to remote code execution (RCE). The vulnerability, tracked as CVE-2026-23918 (CVSS score: 8.8), has been described as a case of "double free and possible RCE" in the HTTP/2 protocol handling. This issue affects Apache HTTP Server 2.4.66 and has been addressed in version 2.4.67. Striga.ai co-founder Bartlomiej Dmitruk and ISEC.pl researcher Stanislaw Strzalkowski have been credited with discovering and reporting the vulnerability. When reached for comment, Dmitruk told The Hacker News via email that the severity of CVE-2026-23918 is critical, as it can be exploited to achieve denial-of-service (DoS) and RCE. Additional details of the vulnerability are below - CVE-2026-23918 is a double-free in Apache httpd 2.4.66 mod_http2 , specifically in the stream cleanup path of h2_mplx.c. T...

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) on Friday added a recently disclosed security flaw impacting various Linux distributions to its Known Exploited Vulnerabilities ( KEV ) catalog, citing evidence of active exploitation in the wild. The vulnerability, tracked as CVE-2026-31431 (CVSS score: 7.8), is a case of local privilege escalation (LPE) flaw that could allow an unprivileged local user to obtain root. The nine-year-old flaw is also tracked as Copy Fail by Theori and Xint. Fixes have been made available in Linux kernel versions 6.18.22, 6.19.12, and 7.0. "Linux Kernel contains an incorrect resource transfer between spheres vulnerability that could allow for privilege escalation," CISA said in an advisory. In a write-up published earlier this week, the researchers said Copy Fail is the result of a logic bug in the Linux kernel's authentication cryptographic template that allows an attacker to reliably trigger privilege escalation tri...

Cybersecurity researchers have disclosed details of a Linux local privilege escalation (LPE) flaw that could allow an unprivileged local user to obtain root. The high-severity vulnerability tracked as CVE-2026-31431 (CVSS score: 7.8) has been codenamed Copy Fail by Xint.io and Theori. "An unprivileged local user can write four controlled bytes into the page cache of any readable file on a Linux system, and use that to gain root," the vulnerability research team at Xint.io and Theori said . At its core, the vulnerability stems from a logic flaw in the Linux kernel's cryptographic subsystem, specifically within the algif_aead module. The issue was introduced in a source code commit made in August 2017. Successful exploitation of the shortcoming could allow a simple 732-byte Python script to edit a setuid binary and obtain root on essentially all Linux distributions shipped since 2017, including Amazon Linux, RHEL, SUSE, and Ubuntu. The Python exploit involves four ...

The threat actor known as Harvester has been attributed to a new Linux version of its GoGra backdoor deployed as part of attacks likely targeting entities in South Asia. "The malware uses the legitimate Microsoft Graph API and Outlook mailboxes as a covert command-and-control (C2) channel, allowing it to bypass traditional perimeter network defenses," the Symantec and Carbon Black Threat Hunter Team said in a report shared with The Hacker News. The cybersecurity company said it identified artifacts uploaded to the VirusTotal platform from India and Afghanistan, suggesting that the two countries may be the target of the espionage activity. Harvester was first publicly documented by Symantec in late 2021, linking it to an information-stealing campaign aimed at telecommunications, government, and information technology sectors in South Asia since June 2021, using a bespoke implant called Graphon that used the Microsoft Graph API for C2. Subsequent activity flagged in Au...

Microsoft has released out-of-band updates to address a security vulnerability in ASP.NET Core that could allow an attacker to escalate privileges. The vulnerability, tracked as CVE-2026-40372 , carries a CVSS score of 9.1 out of 10.0. It's rated Important in severity. An anonymous researcher has been credited with discovering and reporting the flaw. "Improper verification of cryptographic signature in ASP.NET Core allows an unauthorized attacker to elevate privileges over a network," Microsoft said in a Tuesday advisory. "An attacker who successfully exploited this vulnerability could gain SYSTEM privileges." The tech giant said an attacker could abuse the vulnerability to disclose files and modify data, but emphasized that successful exploitation hinges on three prerequisites - The application uses Microsoft.AspNetCore.DataProtection 10.0.6 from NuGet (either directly or through a package that depends on it, such as Microsoft.AspNetCore.DataProtection.S...

Your attack surface no longer lives on one operating system, and neither do the campaigns targeting it. In enterprise environments, attackers move across Windows endpoints, executive MacBooks, Linux infrastructure, and mobile devices, taking advantage of the fact that many SOC workflows are still fragmented by platform.  For security leaders, this creates a costly operational gap : slower validation, limited early-stage visibility, more escalations, and more time for attackers to steal credentials, establish persistence, or move deeper before the response fully begins. The Multi-OS Attack Problem SOCs Aren’t Ready For A multi-OS attack can turn one threat into several different investigations at once. The campaign may follow a different path depending on the system it reaches, which breaks the speed and consistency SOC teams rely on during early triage. Instead of moving through one clear validation pro...

Threat actors are increasingly using HTTP cookies as a control channel for PHP-based web shells on Linux servers and to achieve remote code execution, according to findings from the Microsoft Defender Security Research Team. "Instead of exposing command execution through URL parameters or request bodies, these web shells rely on threat actor-supplied cookie values to gate execution, pass instructions, and activate malicious functionality," the tech giant said . The approach offers added stealth as it allows malicious code to stay dormant during normal application execution and activate the web shell logic only when specific cookie values are present. This behavior, Microsoft noted, extends to web requests, scheduled tasks, and trusted background workers. The malicious activity takes advantage of the fact that cookie values are available at runtime through the $_COOKIE superglobal variable, allowing attacker-supplied inputs to be consumed with...

A long-term and ongoing campaign attributed to a China-nexus threat actor has embedded itself in telecom networks to conduct espionage against government networks. The strategic positioning activity, which involves implanting and maintaining stealthy access mechanisms within critical environments, has been attributed to Red Menshen , a threat cluster that's also tracked as Earth Bluecrow, DecisiveArchitect, and Red Dev 18. The group has a track record of striking telecom providers across the Middle East and Asia since at least 2021. Rapid7 described the covert access mechanisms as "some of the stealthiest digital sleeper cells" ever encountered in telecommunications networks. The campaign is characterized by the use of kernel-level implants, passive backdoors, credential-harvesting utilities, and cross-platform command frameworks, giving the threat actor the ability to persistently inhabit networks of interest. One of the most recognized tools in its malware arsenal i...

Cybersecurity researchers have disclosed a critical security flaw impacting the GNU InetUtils telnet daemon (telnetd) that could be exploited by an unauthenticated remote attacker to execute arbitrary code with elevated privileges. The vulnerability, tracked as CVE-2026-32746 , carries a CVSS score of 9.8 out of 10.0. It has been described as a case of out-of-bounds write in the LINEMODE Set Local Characters (SLC) suboption handler that results in a buffer overflow, ultimately paving the way for code execution. Israeli cybersecurity company Dream, which discovered and reported the flaw on March 11, 2026, said it affects all versions of the Telnet service implementation through 2.7. A fix for the vulnerability is expected to be available no later than April 1, 2026. "An unauthenticated remote attacker can exploit this by sending a specially crafted message during the initial connection handshake — before any login prompt appears," Dream said in an alert. "Successful...

A high-severity security flaw affecting default installations of Ubuntu Desktop versions 24.04 and later could be exploited to escalate privileges to the root level. Tracked as CVE-2026-3888 (CVSS score: 7.8), the issue could allow an attacker to seize control of a susceptible system. "This flaw (CVE-2026-3888) allows an unprivileged local attacker to escalate privileges to full root access through the interaction of two standard system components: snap-confine and systemd-tmpfiles," the Qualys Threat Research Unit (TRU) said . "While the exploit requires a specific time-based window (10–30 days), the resulting impact is a complete compromise of the host system."  The problem, Qualys noted, stems from the unintended interaction of snap-confine, which manages execution environments for snap applications by creating a sandbox, and systemd-tmpfiles, which automatically cleans up temporary files and directories (e.g.,/tmp, /run, and /var/tmp) older than a defined ...

Cybersecurity researchers have disclosed multiple security vulnerabilities within the Linux kernel's AppArmor module that could be exploited by unprivileged users to circumvent kernel protections, escalate to root, and undermine container isolation guarantees. The nine confused deputy vulnerabilities have been collectively codenamed CrackArmor by the Qualys Threat Research Unit (TRU). The cybersecurity company said the issue has existed since 2017. No CVE identifiers have been assigned to the shortcomings. AppArmor is a Linux security module that provides mandatory access control (MAC) and secures the operating system against external or internal threats by preventing known and unknown application flaws from being exploited. It has been included in the mainline Linux kernel since version 2.6.36. "This 'CrackArmor' advisory exposes a confused deputy flaw allowing unprivileged users to manipulate security profiles via pseudo-files, bypass user-namespace restricti...

Cybersecurity researchers have discovered a new malware called KadNap that's primarily targeting Asus routers to enlist them into a botnet for proxying malicious traffic. The malware, first detected in the wild in August 2025, has expanded to over 14,000 infected devices, with more than 60% of victims located in the U.S., according to the Black Lotus Labs team at Lumen. A lesser number of infections have been detected in Taiwan, Hong Kong, Russia, the U.K., Australia, Brazil, France, Italy, and Spain. "KadNap employs a custom version of the Kademlia Distributed Hash Table ( DHT ) protocol, which is used to conceal the IP address of their infrastructure within a peer-to-peer system to evade traditional network monitoring," the cybersecurity company said in a report shared with The Hacker News. Compromised nodes in the network leverage the DHT protocol to locate and connect with a command-and-control (C2) server, thereby making it resilient to detection and disrupt...

A previously unknown threat actor tracked as UAT-9921 has been observed leveraging a new modular framework called VoidLink in its campaigns targeting the technology and financial services sectors, according to findings from Cisco Talos. "This threat actor seems to have been active since 2019, although they have not necessarily used VoidLink over the duration of their activity," researchers Nick Biasini, Aaron Boyd, Asheer Malhotra, and Vitor Ventura said . "UAT-9921 uses compromised hosts to install VoidLink command-and-control (C2), which are then used to launch scanning activities both internal and external to the network." VoidLink was first documented by Check Point last month, describing it as a feature-rich malware framework written in Zig designed for long-term, stealthy access to Linux-based cloud environments. It's assessed to be the work of a single developer with assistance from a large language model (LLM) to flesh out its internals based on a p...

Cybersecurity researchers have disclosed details of a new botnet operation called SSHStalker that relies on the Internet Relay Chat ( IRC ) communication protocol for command-and-control (C2) purposes. "The toolset blends stealth helpers with legacy-era Linux exploitation: Alongside log cleaners (utmp/wtmp/lastlog tampering) and rootkit-class artifacts, the actor keeps a large back-catalog of Linux 2.6.x-era exploits (2009–2010 CVEs)," cybersecurity company Flare said . "These are low value against modern stacks, but remain effective against 'forgotten' infrastructure and long-tail legacy environments." SSHStalker combines IRC botnet mechanics with an automated mass-compromise operation that uses an SSH scanner and other readily available scanners to co-opt susceptible systems into a network and enroll them in IRC channels.

Cybersecurity researchers have taken the wraps off a gateway-monitoring and adversary-in-the-middle (AitM) framework dubbed DKnife that's operated by China-nexus threat actors since at least 2019. The framework comprises seven Linux-based implants that are designed to perform deep packet inspection, manipulate traffic, and deliver malware via routers and edge devices. Its primary targets seem to be Chinese-speaking users, an assessment based on the presence of credential harvesting phishing pages for Chinese email services, exfiltration modules for popular Chinese mobile applications like WeChat, and code references to Chinese media domains. "DKnife's attacks target a wide range of devices, including PCs, mobile devices, and Internet of Things (IoT) devices," Cisco Talos researcher Ashley Shen noted in a Thursday report. "It delivers and interacts with the ShadowPad and DarkNimbus backdoors by hijacking binary downloads and Android application updates....

A critical security flaw has been disclosed in the GNU InetUtils telnet daemon ( telnetd ) that went unnoticed for nearly 11 years. The vulnerability, tracked as CVE-2026-24061 , is rated 9.8 out of 10.0 on the CVSS scoring system. It affects all versions of GNU InetUtils from version 1.9.3 up to and including version 2.7. "Telnetd in GNU Inetutils through 2.7 allows remote authentication bypass via a '-f root' value for the USER environment variable," according to a description of the flaw in the NIST National Vulnerability Database (NVD). In a post on the oss-security mailing list, GNU contributor Simon Josefsson said the vulnerability can be exploited to gain root access to a target system - The telnetd server invokes /usr/bin/login (normally running as root) passing the value of the USER environment variable received from the client as the last parameter. If the client supply [sic] a carefully crafted USER environment value being the string "-f root...