network security | Breaking Cybersecurity News | The Hacker News

A critical security vulnerability impacting ShowDoc , a document management and collaboration service popular in China, has come under active exploitation in the wild. The vulnerability in question is CVE-2025-0520 (aka CNVD-2020-26585), which carries a CVSS score of 9.4 out of 10.0. It relates to a case of unrestricted file upload that stems from improper validation of file extension, allowing an attacker to upload arbitrary PHP files and achieve remote code execution. "[In] ShowDoc version before 2.8.7, an unrestricted and unauthenticated file upload issue is found and [an] attacker is able to upload a web shell and execute arbitrary code on server," according to an advisory released by Vulhub.  The vulnerability was addressed in ShowDoc version 2.8.7 , which was shipped in October 2020. The current version of the software is 3.8.1 . According to new details shared by Caitlin Cond...

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) on Monday added half a dozen security flaws to its Known Exploited Vulnerabilities ( KEV ) catalog, citing evidence of active exploitation. The list of vulnerabilities is as follows - CVE-2026-21643 (CVSS score: 9.1) -  An SQL injection vulnerability in  Fortinet FortiClient EMS that could allow an unauthenticated attacker to execute unauthorized code or commands via specifically crafted HTTP requests. CVE-2020-9715 (CVSS score: 7.8) - A use-after-free vulnerability in Adobe Acrobat Reader that could result in remote code execution. CVE-2023-36424 (CVSS score: 7.8) - An out-of-bounds read vulnerability in Microsoft Windows Common Log File System Driver that could result in privilege escalation. CVE-2023-21529 (CVSS score: 8.8) - A deserialization of untrusted data in Microsoft Exchange Server that could allow an authenticated attacker to achieve remote code execution.  CVE-2025-60710 (CVSS score: 7.8) - An i...

Monday is back, and the weekend’s backlog of chaos is officially hitting the fan. We are tracking a critical zero-day that has been quietly living in your PDFs for months, plus some aggressive state-sponsored meddling in infrastructure that is finally coming to light. It is one of those mornings where the gap between a quiet shift and a full-blown incident response is basically non-existent. The variety this week is particularly nasty. We have AI models being turned into autonomous exploit engines, North Korean groups playing the long game with social engineering, and fileless malware hitting enterprise workflows. There is also a major botnet takedown and new research proving that even fiber optic cables can be used to eavesdrop on your private conversations. Skim this before your next meeting. Let’s get into it. ⚡ Threat of the Week Adobe Acrobat Reader 0-Day Under Attack   — Adobe released emergency updates to fix a critical...

Cybersecurity researchers have flagged a new variant ofmalware called Chaos that'scapable of hitting misconfigured cloud deployments, marking an expansion of the botnet's targeting infrastructure. "Chaos malware is increasingly targeting misconfigured cloud deployments, expanding beyond its traditional focus on routers and edge devices," Darktrace said in a new report. Chaos was first documented by Lumen Black Lotus Labs in September 2022, describing it as a cross-platform malware capable of targeting Windows and Linux environments to run remote shell commands, drop additional modules, propagate to other hosts by brute-forcing SSH keys, mine cryptocurrency, and launch distributed denial-of-service (DDoS) attacks via HTTP, TLS, TCP, UDP, and WebSocket. The malware is assessed to be an evolution of another DDoS malware known as Kaiji  that has singled out misconfigured Docker instances.It's currently not known wh...

Cybersecurity researchers have lifted the curtain on a stealthy botnet that's designed for distributed denial-of-service (DDoS) attacks. Called Masjesu , the botnet has been advertised via Telegram as a DDoS-for-hire service since it first surfaced in 2023. It's capable of targeting a wide range of IoT devices, such as routers and gateways, spanning multiple architectures. "Built for persistence and low visibility, Masjesu favors careful, low-key execution over widespread infection, deliberately avoiding blocklisted IP ranges such as those belonging to the Department of Defense (DoD) to ensure long-term survival," Trellix security researcher Mohideen Abdul Khader F said in a Tuesday report. It's worth noting that the commercial offering also goes by the moniker XorBot owing to its use of XOR-based encryption to conceal strings, configurations, and payload data. It was first documented by Chinese security vendor NSFOCUS in December 2023, linking it to an ope...

The Russia-linked threat actor known as APT28 (aka Forest Blizzard) has been linked to a new campaign that has compromised insecure MikroTik and TP-Link routers and modified their settings to turn them into malicious infrastructure under their control as part of a cyber espionage campaign since at least May 2025. The large-scale exploitation campaign has been codenamed   FrostArmada by Lumen's Black Lotus Labs, with Microsoft describing it as an effort to exploit vulnerable home and small office (SOHO) internet devices to hijack DNS traffic and enable passive collection of network data. "Their technique modified DNS settings on compromised routers to hijack local network traffic to capture and exfiltrate authentication credentials," Black Lotus Labs said in a report shared with The Hacker News. "When targeted domains were requested by a user, the actor redirected traffic to an attacker-in-the-middle (AitM) node, where those credentials were harv...

This week had real hits. The key software got tampered with. Active bugs showed up in the tools people use every day. Some attacks didn’t even need much effort because the path was already there. One weak spot now spreads wider than before. What starts small can reach a lot of systems fast. New bugs, faster use, less time to react. That’s this week. Read through it. ⚡ Threat of the Week Axios npm Package Compromised by N. Korean Hackers —Threat actors with ties to North Korea seized control of the npm account belonging to the lead maintainer of Axios, a popular npm package with nearly 100 million weekly downloads, to push malicious versions containing a cross-platform malware dubbed WAVESHAPER.V2. The activity has been attributed to a financially motivated threat actor known as UNC1069. The incident demonstrates how quickly the compromise of a popular npm package can have ripple effects through the ecosystem. T...

Cisco has released updates to address a critical security flaw in the Integrated Management Controller (IMC) that, if successfully exploited, could allow an unauthenticated, remote attacker to bypass authentication and gain access to the system with elevated privileges. The vulnerability, tracked as CVE-2026-20093, carries a CVSS score of 9.8 out of a maximum of 10.0. "This vulnerability is due to incorrect handling of password change requests," Cisco said in an advisory released Wednesday. "An attacker could exploit this vulnerability by sending a crafted HTTP request to an affected device." "A successful exploit could allow the attacker to bypass authentication, alter the passwords of any user on the system, including an Admin user, and gain access to the system as that user." Security researcher "jyh" has been credited with discovering and reporting the vulnerability. The shortcoming affects the following products regardless of the dev...

Some weeks are loud. This one was quieter but not in a good way. Long-running operations are finally hitting courtrooms, old attack methods are showing up in new places, and research that stopped being theoretical right around the time defenders stopped paying attention. There's a bit of everything this week. Persistence plays, legal wins, influence ops, and at least one thing that looks boring until you see what it connects to. All of it below. Let's go. ⚡ Threat of the Week Citrix Flaw Comes Under Active Exploitation — A critical security flaw in Citrix NetScaler ADC and NetScaler Gateway (CVE-2026-3055, CVSS score: 9.3) has come under active exploitation as of March 27, 2026. The vulnerability refers to a case of insufficient input validation leading to memory overread, which an attacker could exploit to leak potentially sensitive information. Per Citrix, successful exploitation of the flaw hinges on the appliance being configured as a SAML Identity Provider (SAML IDP)...

Cybersecurity researchers have discovered a remote access toolkit of Russian-origin that's distributed via malicious Windows shortcut (LNK) files that are disguised as private key folders. The CTRL toolkit, according to Censys, is custom-built using .NET and includes various executables" to facilitate credential phishing, keylogging, Remote Desktop Protocol (RDP) hijacking, and reverse tunneling via Fast Reverse Proxy (FRP). "The executables provide encrypted payload loading, credential harvesting via a polished Windows Hello phishing UI, keylogging, RDP session hijacking, and reverse proxy tunneling through FRP," Censys security researcher Andrew Northern said . The attack surface management platform said it recovered CTRL from an open directory at 146.19.213[.]155 in February 2026. Attack chains distributing the toolkit rely on a weaponized LNK file ("Private Key #kfxm7p9q_yek.lnk") with a folder icon to trick users into double-clicking it. This tri...

A recently disclosed critical security flaw impacting Citrix NetScaler ADC and NetScaler Gateway is witnessing active reconnaissance activity, according to Defused Cyber and watchTowr . The vulnerability, CVE-2026-3055 (CVSS score: 9.3), refers to a case of insufficient input validation leading to memory overread, which an attacker could exploit to leak potentially sensitive information. Per Citrix, successful exploitation of the flaw hinges on the appliance being configured as a SAML Identity Provider (SAML IDP). "We are now observing auth method fingerprinting activity against NetScaler ADC/Gateway in the wild," Defused Cyber said in a post on X. "Attackers are probing /cgi/GetAuthMethods to enumerate enabled authentication flows in our Citrix honeypots." This is likely an attempt on the part of threat actors to determine if NetScaler ADC and NetScaler Gateway are indeed configured as a SAML IDP. In a similar warning, watchTowr said it has detected active...

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) on Friday added a critical security flaw impacting F5 BIG-IP Access Policy Manager (APM) to its Known Exploited Vulnerabilities ( KEV ) catalog, citing evidence of active exploitation. The vulnerability in question is CVE-2025-53521 (CVSS v4 score: 9.3), which could allow a threat actor to achieve remote code execution. "When a BIG-IP APM access policy is configured on a virtual server, specific malicious traffic can lead to Remote Code Execution (RCE)," according to a description of the flaw in CVE.org. While the shortcoming was initially categorized and remediated as a denial-of-service (DoS) vulnerability with a CVSS v4 score of 8.7, F5 said it has been reclassified as a case of RCE in light of "new information obtained in March 2026." The company has since updated its advisory to confirm that the vulnerability "has been exploited in the vulnerable BIG-IP versions." It did not shar...

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...

Most teams have security tools in place. Alerts are firing, dashboards look clean, threat intel is flowing in. On the surface, everything feels under control. But one question usually stays unanswered: Would your defenses actually stop a real attack? That’s where things get shaky. A control exists, so it’s assumed to work. A detection rule is active, so it’s expected to catch something. But very few teams are consistently testing how all of this holds up when someone is actively trying to break through, step by step. This is exactly the gap this webinar focuses on. Exposure-Driven Resilience: Automate Testing to Validate & Improve Your Security Posture is a practical session built around one idea: stop guessing, start proving. Instead of relying on occasional testing or assumptions, it shows how to validate your security posture continuously using real attacker behavior. The session walks through how to pressure-test both your controls and your processes, how to use threa...

Unmasking impostors is something the art world has faced for decades, and there are valuable lessons from the works of Elmyr de Hory that can apply to the world of defensive cybersecurity. During the 1960s, de Hory gained infamy as a premier forger, passing off counterfeit masterworks of Picasso, Matisse, and Renoir to unsuspecting collectors and renowned museums. Over the next several decades, more than a thousand of his works slipped past experts who relied on trusted signatures, familiar patterns, and reputable provenance. It’s not unlike the challenges SOCs are facing now. We’re firmly in the Age of Imitation. Cyberattackers, equipped with AI, are mastering the art of imitating the familiar, posing as trusted users and masking their activity within legitimate processes and ordinary network traffic. As history shows, it’s often easier to identify impostors when you know what to look for. Key takeaways for defenders: Mimicry is the new normal: 81% of attacks are malware-free Ag...

The U.S. Federal Communications Commission (FCC) said on Monday that it was banning the import of new, foreign-made consumer routers, citing "unacceptable" risks to cyber and national security. The action was designed to safeguard Americans and the underlying communications networks the country relies on, FCC Chairman Brendan Carr said in a post on X. The development means that new models of foreign-produced routers will no longer be eligible for marketing or sale in the U.S. The move comes in the wake of a national security determination provided by Executive Branch Agencies, Carr added. To that end, all consumer-grade routers manufactured in foreign countries have been added to the Covered List , unless they have been granted a Conditional Approval by the Department of War (DoW) or the Department of Homeland Security (DHS) after determining that they do not pose any risks. As of writing, the approved list only includes drone systems and software-defined radios (SDRs) ...

A large-scale malvertising campaign active since January 2026 has been observed targeting U.S.-based individuals searching for tax-related documents to serve rogue installers for ConnectWise ScreenConnect that drop a tool named HwAudKiller to blind security programs using the bring your own vulnerable driver ( BYOVD ) technique. "The campaign abuses Google Ads to serve rogue ScreenConnect (ConnectWise Control) installers, ultimately delivering a BYOVD EDR killer that drops a kernel driver to blind security tools before further compromise," Huntress researcher Anna Pham said in a report published last week. The cybersecurity vendor said it identified over 60 instances of malicious ScreenConnect sessions tied to the campaign. The attack chain stands out for a couple of reasons. Unlike recent campaigns highlighted by Microsoft that leverage tax-themed lures, the newly flagged activity employs commercial cloaking services to avoid detection by security scanners and abuses a ...

Cybersecurity has changed fast. Roles are more specialized, and tooling is more advanced. On paper, this should make organizations more secure. But in practice, many teams struggle with the same basic problems they faced years ago: unclear risk priorities, misaligned tooling decisions, and difficulty explaining security issues in terms the business understands. These challenges do not usually come from a lack of effort. They emerge from something more subtle, a gradual loss of foundational understanding as specialization accelerates. Specialization itself is not the problem. A lack of context is. When security teams do not have a shared understanding of how the business, systems, and risks fit together, even strong technical execution starts to break down. Over time, that gap shows up in the way programs are designed, tools are chosen, and incidents are handled. Unfortunately, I’ve seen this pattern repeatedly when assisting with ...

A 26-year-old Russian citizen has been sentenced in the U.S. to 6.75 years (81 months) in prison for his role in assisting major cybercrime groups, including the Yanluowang ransomware crew, in conducting numerous attacks against U.S. companies and other organizations. According to the U.S. Department of Justice (DoJ), Aleksei Olegovich Volkov facilitated dozens of ransomware attacks across the U.S., causing more than $9 million in actual losses and over $24 million in intended losses. Volkov was arrested on January 18, 2024, in Italy and extradited to the U.S. to face charges. He pleaded guilty to the crimes in November 2025. Volkov is said to have served as an initial access broker responsible for obtaining unauthorized access to computer networks and systems belonging to various organizations and selling that access to other criminal groups, including ransomware actors. This was accomplished by exploiting vulnerabilities or finding ways to access the networks without authorizati...

Citrix has released security updates to address two vulnerabilities in NetScaler ADC and NetScaler Gateway, including a critical flaw that could be exploited to leak sensitive data from the application. The vulnerabilities are listed below - CVE-2026-3055 (CVSS score: 9.3) - Insufficient input validation leading to memory overread CVE-2026-4368 (CVSS score: 7.7) - Race condition leading to user session mixup Cybersecurity company Rapid7 said that CVE-2026-3055 refers to an out-of-bounds read that could be exploited by unauthenticated remote attackers to leak potentially sensitive information from the appliance's memory. However, for exploitation to be successful, the Citrix ADC or Citrix Gateway appliance must be configured as a SAML Identity Provider (SAML IDP), which means default configurations are unaffected. To determine if the device has been configured as a SAML IDP Profile, Citrix is urging customers to inspect their NetScaler Configuration for the specified st...