Fake Microsoft Alerts Used to Deploy North Korean NarwhalRAT Malware

Summary

North Korean state-sponsored group ScarCruft (APT37) is deploying a new Python-based remote access trojan called NarwhalRAT via spear-phishing emails impersonating Microsoft Account security alerts. The attack uses a multi-stage infection chain starting with LNK files in ZIP archives that download batch scripts, which then retrieve the malware payload and establish persistence through scheduled tasks. The malware communicates with C2 servers using Korean websites and pCloud cloud storage as a dead drop resolver.

Full text

Fake Microsoft Alerts Used to Deploy North Korean NarwhalRAT Malware Ravie LakshmananJun 16, 2026Malware / Cyber Attack The North Korean state-sponsored hacking group known as ScarCruft (aka APT37) has been observed using spear-phishing messages impersonating Microsoft Account security notifications to deliver malware called NarwhalRAT. "The attack email contained a message impersonating an MS account security alert," the Genians Security Center (GSC) said. "It was designed to create concern over possible account compromise and OTP abuse, thereby inducing the recipient to execute the attachment." "The email body instructed the recipient to refer to the attached advisory. However, the actual attachment was not an HWP [Hangul Word Processor] document, but a ZIP archive that contained a malicious LNK file." The email message claims "abnormal activity" related to repeated generation of one-time passwords, passing it off as a phishing attempt aimed at the target's Microsoft Account by a third-party, and urging them to change their password. The end goal of the phishing message is to induce a false sense of urgency and deceive the victim into interpreting the email as a legitimate security alert. The LNK file, once launched, initiates a multi-stage infection chain that employs intermediary batch scripts to download and install NarwhalRAT, along with retrieving the legitimate Python executable from the official website and a Windows security catalog (CAT) file. Persistence is achieved via a scheduled task, which is configured to launch the CAT file responsible for fetching and running the main payload in memory without leaving any artifacts on disk. The Python-based malware is equipped to log keystrokes, capture screenshots (with support for high-resolution images), record ambient audio, upload directory contents, collect active window details, gather data from USB media, execute instructions issued by a command-and-control (C2) server, and switch C2 servers. The moniker NarwhalRAT is a reference to the malware's use of "%APPDATA%\naverwhale" to stage the harvested information on the compromised host. The hidden directory's name is an attempt to evade detection by masquerading as Naver Whale, a web browser developed by South Korean tech company Naver Corporation. APT37's deployment of NarwhalRAT is noteworthy as it marks a departure from RokRAT, a malware family exclusively attributed to the hacking group. "From a C2 infrastructure perspective, the malware uses Korean websites, including 'daehoat[.]com' and 'novel21[.]co.kr,' as primary communication relays, while also implementing communication functionality based on the pCloud cloud storage API," the South Korean cybersecurity company said. "In particular, pCloud-specific routines that process the 'folderid' and 'auth' parameters were identified within the code. This indicates that the malware was designed to use a legitimate cloud service as a secondary C2 channel in the form of a dead drop resolver." Genians said the activity shares "multiple similarities" with prior Python-based attacks orchestrated by ScarCruft, including a spear-phishing campaign that has used ticket confirmation and event invites lures to trick potential targets into opening ZIP archives containing LNK files. The attack chain plays out in a similar fashion in that the LNK file acts as a conduit for an obfuscated batch script downloaded from a remote C2 server, which then downloads the Python binary and a CAT file, ultimately resulting in the deployment of a compiled Python script capable of remote command execution and sending the results back to the C2 server. Interestingly, the scheduled task names used to set up persistence follow a similar naming convention. While the NarwhalRAT infection creates a scheduled task called "MicrosoftUserInterfacePicturesUpdateTackMachine," the second chain uses the name "MicrosoftMusicLibrariesPackageTaskMachine." "Overall, NarwhalRAT is assessed to be an advanced RAT malware that integrates a Python-based multi-stage loader, an in-memory execution structure, a multi-C2 operational framework, and selective information collection functions," Genians said. Found this article interesting? Follow us on Google News, Twitter and LinkedIn to read more exclusive content we post. SHARE     Tweet Share Share Share SHARE  APT37, cybersecurity, Malware, Microsoft, North Korea, Phishing, Remote Access Trojan, ScarCruft, Spear Phishing ⚡ Top Stories This Week Chrome V8 Zero-Day CVE-2026-11645 Exploited in the Wild - Patch Now Researchers Build Self-Replicating AI Worm That Operates Entirely on Local, Open-Weight Models Microsoft Defender RoguePlanet Zero-Day Grants SYSTEM Access on Updated Windows Anthropic Releases Claude Fable 5, Its Most Powerful AI Yet, With Cyber Safeguards Microsoft Patches Record 206 Flaws, Including Three Zero-Days and Critical RCE Bugs Ivanti, Fortinet, and SAP Release Patches for Multiple Critical Vulnerabilities Cybersecurity Stars Awards 2026: Winners Announced Across 95 Categories ThreatsDay Bulletin: Worm Code Leaked, AI Agent Phished, Claude Code Patch + 28 New Stories New GreatXML Exploit Bypasses Windows BitLocker via Recovery Partition XML Files Agentjacking Attack Tricks AI Coding Agents Into Running Malicious Code China-Linked Hackers Backdoored Linux Login Software to Hide for Nearly a Decade Critical Splunk Enterprise Flaw Lets Attackers Run Code Without Authentication U.S. Orders Anthropic to Suspend Fable 5 and Mythos 5 Access for Foreign Nationals Over 400 Arch Linux AUR Packages Hijacked to Deploy Infostealer and eBPF Rootkit ⭐ Featured Resources Get the 2026 Guide to Govern and Secure Enterprise AI Agents at Scale [Watch Demo] See Which Security Gaps Attackers Could Exploit First AI Can’t Stop Every Attack. Learn How Zero Trust Can Block What’s Unknown Have You Outgrown Your MDR? 7 Warning Signs Every CISO Should Check

Indicators of Compromise

• domain — daehoat.com
• domain — novel21.co.kr
• malware — NarwhalRAT

Entities