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Notepad++ Update Mechanism Exploited to Deliver Malicious Payloads

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3 unique sources, 5 articles

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Notepad++ version 8.8.9 was released to address a security flaw in its WinGUp update tool that allowed attackers to push malicious executables instead of legitimate updates. Users reported incidents where the updater spawned a malicious AutoUpdater.exe that collected device information and exfiltrated it to a remote site. The flaw was mitigated by enforcing updates only from GitHub and later by requiring signature verification for all updates. Security researchers noted targeted attacks against organizations with interests in East Asia, where Notepad++ processes were used to gain initial access. The attack involved an infrastructure-level compromise at the hosting provider level, allowing malicious actors to intercept and redirect update traffic. The incident commenced in June 2025 and continued until December 2025, with the Notepad++ website later migrated to a new hosting provider. The attackers were likely Chinese state-sponsored threat actors, selectively redirecting update requests from certain users to malicious servers. The hosting provider for the update feature was compromised, enabling targeted traffic redirections. The attackers regained access using previously obtained internal service credentials. Notepad++ has since migrated all clients to a new hosting provider with stronger security and plans to enforce mandatory certificate signature verification in version 8.9.2. The compromise involved shared hosting infrastructure rather than a flaw in the software's code, with attackers gaining access at the hosting provider level to intercept and manipulate traffic bound for the Notepad++ update endpoint. Direct server access by the attackers ended on September 2, 2025, but credentials associated with internal services remained exposed until December 2, 2025, allowing continued traffic redirection. The hosting provider confirmed no additional customers were affected. Notepad++ version 8.9.2 introduced a 'double-lock' design for its update mechanism, including verifying the signed installer from GitHub and checking the signed XML from the notepad-plus-plus.org domain. The auto-updater now removes libcurl.dll to eliminate DLL side-loading risk, removes unsecured cURL SSL options, and restricts plugin management execution to programs signed with the same certificate as WinGUp. Users can exclude the auto-updater during UI installation or deploy the MSI package with the NOUPDATER=1 flag. The threat group Lotus Blossom, linked to China, was involved in the compromise, using a custom backdoor called 'Chrysalis' as part of the attack chain.

Timeline

  1. 17.02.2026 20:29 1 articles · 4h ago

    Notepad++ version 8.9.2 introduces double-lock update mechanism

    Notepad++ version 8.9.2 introduces a 'double-lock' design for its update mechanism, including verifying the signed installer from GitHub and checking the signed XML from the notepad-plus-plus.org domain. The auto-updater now removes libcurl.dll to eliminate DLL side-loading risk, removes unsecured cURL SSL options, and restricts plugin management execution to programs signed with the same certificate as WinGUp. Users can exclude the auto-updater during UI installation or deploy the MSI package with the NOUPDATER=1 flag.

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  2. 11.12.2025 23:04 5 articles · 2mo ago

    Notepad++ Update Mechanism Exploited to Deliver Malicious Payloads

    The compromise involved shared hosting infrastructure rather than a flaw in the software's code. Attackers gained access at the hosting provider level, enabling them to intercept and manipulate traffic bound for the Notepad++ update endpoint. The compromise began in June 2025, with direct server access ending on September 2, 2025, but internal service credentials remained exposed until December 2, 2025. The hosting provider confirmed no additional customers were affected. The threat group Lotus Blossom, linked to China, was involved in the compromise, using a custom backdoor called 'Chrysalis' as part of the attack chain.

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Information Snippets

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Critical Pre-Auth RCE Vulnerability in BeyondTrust Remote Support and PRA

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Lotus Blossom Hacking Group Exploits Notepad++ Hosting Breach to Deploy Chrysalis Backdoor

The China-linked Lotus Blossom hacking group exploited a hosting provider breach to deliver a previously undocumented backdoor, Chrysalis, to Notepad++ users. The attack, which occurred between June and December 2025, involved hijacking update traffic and exploiting insufficient update verification controls in older versions of the software. The group used a multi-layered shellcode loader and integrated undocumented system calls to enhance stealth and resilience. The breach was discovered and mitigated in December 2025, with Notepad++ migrating to a new hosting provider and rotating all credentials. The Chrysalis backdoor is a feature-rich implant capable of gathering system information, executing commands, and maintaining persistence. It communicates with a command-and-control (C2) server to receive additional instructions. The C2 server is currently offline, but the malware's capabilities suggest ongoing development and adaptation by the threat actor.

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Active Exploitation of Unpatched Cisco AsyncOS Zero-Day in SEG and SEWM Appliances

Cisco has identified an unpatched, critical zero-day vulnerability (CVE-2025-20393) in AsyncOS, affecting Secure Email Gateway (SEG) and Secure Email and Web Manager (SEWM) appliances. The flaw is actively exploited by a Chinese threat group, UAT-9686, to deploy backdoors and other malware. The attacks have been ongoing since at least late November 2025. Cisco has released security updates for the vulnerability and recommends securing and restricting access to vulnerable appliances. The vulnerability allows threat actors to execute arbitrary commands with root privileges and deploy tools like AquaShell, AquaTunnel, Chisel, and AquaPurge. CISA has added CVE-2025-20393 to its Known Exploited Vulnerabilities (KEV) catalog, requiring FCEB agencies to apply mitigations by December 24, 2025. Additionally, GreyNoise detected a coordinated campaign targeting enterprise VPN infrastructure, including Cisco SSL VPN and Palo Alto Networks GlobalProtect portals.

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Sneeit WordPress RCE Exploited in Active Attacks

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Critical React Server Components (RSC) Bugs Enable Unauthenticated Remote Code Execution

A critical security vulnerability (CVE-2025-55182, CVSS 10.0) in React Server Components (RSC) allows unauthenticated remote code execution due to unsafe deserialization of payloads. The flaw affects multiple versions of React and Next.js, potentially impacting any application using RSC. The issue has been patched, but 39% of cloud environments remain vulnerable. Cloudflare experienced a widespread outage due to an emergency patch for this vulnerability, and multiple China-linked hacking groups have begun exploiting it. NHS England National CSOC has warned of the likelihood of continued exploitation in the wild. Major companies such as Google Cloud, AWS, and Cloudflare immediately responded to the vulnerability. The security researcher Lachlan Davidson disclosed the vulnerability on November 29, 2025, to the Meta team. The flaw has been dubbed React2Shell, a nod to the Log4Shell vulnerability discovered in 2021. 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Cloudflare started investigating issues on December 5 at 08:56 UTC, and a fix was rolled out within half an hour, but by that time outages had been reported by several major internet services, including Zoom, LinkedIn, Coinbase, DoorDash, and Canva. The U.S. Cybersecurity and Infrastructure Security Agency (CISA) added the vulnerability to its Known Exploited Vulnerabilities (KEV) catalog on December 6, 2025, following confirmed active exploitation. The vulnerability is tracked as React2Shell and is related to a remote code execution flaw in React Server Components (RSC). The flaw is due to insecure deserialization in the Flight protocol used by React to communicate between a server and client. The vulnerability affects versions 19.0, 19.1.0, 19.1.1, and 19.2.0 of react-server-dom-webpack, react-server-dom-parcel, and react-server-dom-turbopack. Patched versions of React are 19.0.1, 19.1.2, and 19.2.1. Downstream frameworks impacted include Next.js, React Router, Waku, Parcel, Vite, and RedwoodSDK. Amazon reported attack attempts from Chinese hacking groups like Earth Lamia and Jackpot Panda within hours of public disclosure. Coalition, Fastly, GreyNoise, VulnCheck, and Wiz reported seeing exploitation efforts targeting the flaw. Some attacks involved the deployment of cryptocurrency miners and the execution of "cheap math" PowerShell commands. Censys identified about 2.15 million instances of internet-facing services potentially affected by the vulnerability. Palo Alto Networks Unit 42 confirmed over 30 affected organizations across numerous sectors, with activity consistent with Chinese hacking group UNC5174. Security researcher Lachlan Davidson released multiple proof-of-concept (PoC) exploits for the vulnerability. Another working PoC was published by a Taiwanese researcher with the GitHub handle maple3142. Federal Civilian Executive Branch (FCEB) agencies have until December 26, 2025, to apply the necessary updates to secure their networks. Over 77,000 Internet-exposed IP addresses are vulnerable to the critical React2Shell remote code execution flaw (CVE-2025-55182). Researchers have confirmed that attackers have already compromised over 30 organizations across multiple sectors using the React2Shell flaw. Shadowserver detected 77,664 IP addresses vulnerable to the React2Shell flaw, with approximately 23,700 in the United States. GreyNoise recorded 181 distinct IP addresses attempting to exploit the flaw over the past 24 hours, with most of the traffic appearing automated. Attackers frequently begin with PowerShell commands that perform a basic math function to confirm the device is vulnerable to the remote code execution flaw. Once remote code execution was confirmed, attackers were seen executing base64-encoded PowerShell commands that download additional scripts directly into memory. One observed command executes a second-stage PowerShell script from the external site (23[.]235[.]188[.]3), which is used to disable AMSI to bypass endpoint security and deploy additional payloads. The PowerShell script observed by GreyNoise installs a Cobalt Strike beacon on the targeted device, giving threat actors a foothold on the network. Amazon AWS threat intelligence teams saw rapid exploitation hours after the disclosure of the React CVE-2025-55182 flaw, with infrastructure associated with China-linked APT hacking groups known as Earth Lamia and Jackpot Panda. Palo Alto Networks observed similar exploitation, attributing some of it to UNC5174, a Chinese state-sponsored threat actor believed to be tied to the Chinese Ministry of State Security. The deployed malware in these attacks includes Snowlight and Vshell, both commonly used by Chinese hacking groups for remote access, post-exploitation activity, and to move laterally through a compromised network. Earth Lamia is known for exploiting web application vulnerabilities to target organizations across Latin America, the Middle East, and Southeast Asia. Earth Lamia has historically targeted sectors across financial services, logistics, retail, IT companies, universities, and government organizations. Jackpot Panda primarily targets entities in East and Southeast Asia. The Shadowserver Foundation has identified over 77,000 vulnerable IPs following a scan of exposed HTTP services across a wide variety of exposed edge devices and other applications. Censys observed just over 2.15 million instances of internet-facing services that may be affected by this vulnerability, including exposed web services using React Server Components and exposed instances of frameworks such as Next.js, Waku, React Router, and RedwoodSDK. The bug is a pre-authentication remote code execution (RCE) vulnerability which exists in React Server Components versions 19.0.0, 19.1.0, 19.1.1, and 19.2.0. React issued a security advisory with the relevant patches and updates on December 3. Any internet-accessible server running the affected React Server Components code should be assumed vulnerable until updated as a precaution. AWS observed that many threat actors are attempting to use public PoCs that don’t work in real-world scenarios. AWS noted that the use of these PoCs shows that threat actors prioritize rapid operationalization over thorough testing, attempting to exploit targets with any available tool. Using multiple PoCs to scan for vulnerable environments also gives threat actors a higher chance of identifying vulnerable configurations, even if the PoCs are non-functional. The availability of the PoCs also allows less sophisticated actors to participate in exploitation campaigns. Finally, AWS noted that even failed exploitation attempts create significant noise in logs, potentially masking more sophisticated attacks. The invalid PoCs can give developers a false sense of security when testing for React2Shell. The Shadowserver Foundation detected 28,964 IP addresses vulnerable to the React2Shell flaw as of December 7, 2025, down from 77,664 on December 5, with approximately 10,100 located in the U.S., 3,200 in Germany, and 1,690 in China. Huntress observed attackers targeting numerous organizations via CVE-2025-55182, with a focus on the construction and entertainment industries. The first recorded exploitation attempt on a Windows endpoint by Huntress dates back to December 4, 2025, when an unknown threat actor exploited a vulnerable instance of Next.js to drop a shell script, followed by commands to drop a cryptocurrency miner and a Linux backdoor. Attackers were observed launching discovery commands and attempting to download several payloads from a command-and-control (C2) server. Huntress identified a Linux backdoor called PeerBlight, a reverse proxy tunnel named CowTunnel, and a Go-based post-exploitation implant referred to as ZinFoq. PeerBlight shares code overlaps with two malware families RotaJakiro and Pink that came to light in 2021, installs a systemd service to ensure persistence, and masquerades as a "ksoftirqd" daemon process to evade detection. CowTunnel initiates an outbound connection to attacker-controlled Fast Reverse Proxy (FRP) servers, effectively bypassing firewalls that are configured to only monitor inbound connections. ZinFoq implements a post-exploitation framework with interactive shell, file operations, network pivoting, and timestomping capabilities. Huntress assessed that the threat actor is likely leveraging automated exploitation tooling, supported by the attempts to deploy Linux-specific payloads on Windows endpoints, indicating the automation does not differentiate between target operating systems. PeerBlight supports capabilities to establish communications with a hard-coded C2 server ("185.247.224[.]41:8443"), allowing it to upload/download/delete files, spawn a reverse shell, modify file permissions, run arbitrary binaries, and update itself. ZinFoq beacons out to its C2 server and is equipped to parse incoming instructions to run commands using "/bin/bash," enumerate directories, read or delete files, download more payloads from a specified URL, exfiltrate files and system information, start/stop SOCKS5 proxy, enable/disable TCP port forwarding, alter file access and modification times, and establish a reverse pseudo terminal (PTY) shell connection. ZinFoq takes steps to clear bash history and disguises itself as one of 44 legitimate Linux system services to conceal its presence. CISA has urged federal agencies to patch the React2Shell vulnerability by December 12, 2025, amid reports of widespread exploitation. The vulnerability has been exploited by multiple threat actors in various campaigns to engage in reconnaissance efforts and deliver a wide range of malware families. Wiz observed a "rapid wave of opportunistic exploitation" of the flaw, with a vast majority of the attacks targeting internet-facing Next.js applications and other containerized workloads running in Kubernetes and managed cloud services. Cloudflare reported that threat actors have conducted searches using internet-wide scanning and asset discovery platforms to find exposed systems running React and Next.js applications. Some of the reconnaissance efforts have excluded Chinese IP address spaces from their searches. The observed activity targeted government (.gov) websites, academic research institutions, and critical-infrastructure operators. Early scanning and exploitation attempts originated from IP addresses previously associated with Asia-affiliated threat clusters. Kaspersky recorded over 35,000 exploitation attempts on a single day on December 10, 2025, with the attackers first probing the system by running commands like whoami, before dropping cryptocurrency miners or botnet malware families like Mirai/Gafgyt variants and RondoDox. Security researcher Rakesh Krishnan discovered an open directory hosted on "154.61.77[.]105:8082" that includes a proof-of-concept (PoC) exploit script for CVE-2025–55182 along with two other files: "domains.txt," which contains a list of 35,423 domains, and "next_target.txt," which contains a list of 596 URLs, including companies like Dia Browser, Starbucks, Porsche, and Lululemon. The Shadowserver Foundation reported more than 137,200 internet-exposed IP addresses running vulnerable code as of December 11, 2025, with over 88,900 instances located in the U.S., followed by Germany (10,900), France (5,500), and India (3,600). Google's threat intelligence team linked five more Chinese hacking groups to attacks exploiting the React2Shell vulnerability. The list of state-linked threat groups exploiting the flaw now also includes UNC6600, UNC6586, UNC6588, UNC6603, and UNC6595. GTIG researchers observed numerous discussions regarding CVE-2025-55182 in underground forums, including threads where threat actors shared links to scanning tools, proof-of-concept (PoC) code, and their experiences using these tools. GTIG also spotted Iranian threat actors targeting the flaw and financially motivated attackers deploying XMRig cryptocurrency mining software on unpatched systems. Shadowserver Internet watchdog group is currently tracking over 116,000 IP addresses vulnerable to React2Shell attacks, with over 80,000 in the United States. GreyNoise has observed over 670 IP addresses attempting to exploit the React2Shell remote code execution flaw over the past 24 hours, primarily originating from the United States, India, France, Germany, the Netherlands, Singapore, Russia, Australia, the United Kingdom, and China. Threat actors are exploiting the React2Shell vulnerability to deliver malware families like KSwapDoor and ZnDoor. KSwapDoor is a professionally engineered remote access tool designed with stealth in mind, building an internal mesh network and using military-grade encryption. KSwapDoor impersonates a legitimate Linux kernel swap daemon to evade detection. ZnDoor is a remote access trojan that contacts threat actor-controlled infrastructure to receive and execute commands. ZnDoor supports commands such as shell, interactive_shell, explorer, explorer_cat, explorer_delete, explorer_upload, explorer_download, system, change_timefile, socket_quick_startstreams, start_in_port_forward, and stop_in_port. Google identified five China-nexus groups exploiting React2Shell to deliver various payloads, including MINOCAT, SNOWLIGHT, COMPOOD, HISONIC, and ANGRYREBEL. Microsoft reported that threat actors have used the flaw to run arbitrary commands, set up reverse shells, drop RMM tools, and modify authorized_keys files. Payloads delivered in these attacks include VShell, EtherRAT, SNOWLIGHT, ShadowPad, and XMRig. Threat actors used Cloudflare Tunnel endpoints to evade security defenses and conducted reconnaissance for lateral movement and credential theft. Credential harvesting targeted Azure Instance Metadata Service (IMDS) endpoints for Azure, AWS, GCP, and Tencent Cloud. Threat actors deployed secret discovery tools such as TruffleHog and Gitleaks, along with custom scripts to extract various secrets. Beelzebub detailed a campaign exploiting Next.js flaws to extract credentials and sensitive data, including environment files, SSH keys, cloud credentials, and system files. The malware creates persistence, installs a SOCKS5 proxy, establishes a reverse shell, and installs a React scanner for further propagation. Operation PCPcat has breached an estimated 59,128 servers. The Shadowserver Foundation is tracking over 111,000 IP addresses vulnerable to React2Shell attacks, with over 77,800 instances in the U.S. GreyNoise observed 547 malicious IP addresses from the U.S., India, the U.K., Singapore, and the Netherlands partaking in exploitation efforts over the past 24 hours. The RondoDox botnet has been observed exploiting the critical React2Shell flaw (CVE-2025-55182) to infect vulnerable Next.js servers with malware and cryptominers. First documented by Fortinet in July 2025, RondoDox is a large-scale botnet that targets multiple n-day flaws in global attacks. In November, VulnCheck spotted new RondoDox variants that featured exploits for CVE-2025-24893, a critical remote code execution (RCE) vulnerability in the XWiki Platform. A new report from cybersecurity company CloudSEK notes that RondoDox started scanning for vulnerable Next.js servers on December 8 and began deploying botnet clients three days later. React2Shell is an unauthenticated remote code execution vulnerability that can be exploited via a single HTTP request and affects all frameworks that implement the React Server Components (RSC) 'Flight' protocol, including Next.js. The flaw has been leveraged by several threat actors to breach multiple organizations. North Korean hackers exploited React2Shell to deploy a new malware family named EtherRAT. As of December 30, the Shadowserver Foundation reports detecting over 94,000 internet-exposed assets vulnerable to React2Shell. CloudSEK says that RondoDox has passed through three distinct operational phases this year: Reconnaissance and vulnerability testing from March to April 2025, Automated web app exploitation from April to June 2025, Large-scale IoT botnet deployment from July to today. Regarding React2Shell, the researchers report that RondoDox has focused its exploitation around the flaw significantly lately, launching over 40 exploit attempts within six days in December. During this operational phase, the botnet conducts hourly IoT exploitation waves targeting Linksys, Wavlink, and other consumer and enterprise routers to enroll new bots. After probing potentially vulnerable servers, CloudSEK says that RoundDox started to deploy payloads that included a coinminer (/nuts/poop), a botnet loader and health checker (/nuts/bolts), and a variant of Mirai (/nuts/x86). The 'bolts' component removes competing botnet malware from the host, enforces persistence via /etc/crontab, and kills non-whitelisted processes every 45 seconds, the researchers say. CloudSEK provides a set of recommendations for companies to protect against this RondoDox activity, among them auditing and patching Next.js Server Actions, isolating IoT devices into dedicated virtual LANs, and monitoring for suspicious processes being executed.

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