China-Linked Amaranth-Dragon APT Unleashes Zero-Day WinRAR Exploit in Southeast Asia Cyber Blitz

In a high-stakes cyber espionage campaign that has sent shockwaves through Southeast Asia’s political and security landscape, Check Point Research has uncovered a sophisticated Chinese-linked APT group dubbed Amaranth-Dragon orchestrating a relentless assault on government and law enforcement agencies across the region.

The operation, which Check Point Research is tracking as Amaranth-Dragon, represents a quantum leap in cyber warfare sophistication, leveraging the recently disclosed CVE-2025-8088 WinRAR vulnerability just eight days after its public announcement in August 2025. This lightning-fast weaponization demonstrates the group’s exceptional technical maturity and preparedness for large-scale espionage operations.

Geopolitical Chessboard: Timing Attacks with Political Sensitivities

The campaign’s architecture reveals a chilling level of strategic planning, with attacks meticulously synchronized to coincide with sensitive local political developments, official government decisions, and regional security events. Countries in the crosshairs include Cambodia, Thailand, Laos, Indonesia, Singapore, and the Philippines—nations whose geopolitical positioning makes them prime targets for Chinese intelligence collection.

Check Point researchers emphasize that these campaigns were “narrowly focused” and “tightly scoped,” indicating sophisticated efforts to establish long-term persistence for geopolitical intelligence collection. The attackers have configured their infrastructure to interact only with victims in specific target countries, dramatically minimizing exposure while maximizing intelligence yield.

Technical Masterpiece: The WinRAR Zero-Day Weaponization

The exploitation of CVE-2025-8088 represents a significant escalation in cyber warfare tactics. This now-patched security flaw in RARLAB WinRAR allows arbitrary code execution when specially crafted archives are opened by targets. The speed at which Amaranth-Dragon operationalized this vulnerability—just eight days post-disclosure—underscores their technical sophistication and readiness.

The attack methodology employs a multi-layered approach that begins with spear-phishing emails containing archive files hosted on trusted cloud platforms like Dropbox. This tactic effectively lowers suspicion and bypasses traditional perimeter defenses, making the initial compromise exceptionally difficult to detect.

The Amaranth Loader: A Sophisticated Malware Architecture

At the heart of the operation lies the Amaranth Loader, a malicious DLL that’s launched through DLL side-loading—a long-preferred tactic among Chinese threat actors. This loader shares striking similarities with tools such as DodgeBox, DUSTPAN (aka StealthVector), and DUSTTRAP, previously identified as used by the APT41 hacking crew.

The loader’s architecture is particularly sophisticated, designed to contact external servers to retrieve encryption keys, which are then used to decrypt encrypted payloads from different URLs and execute them directly in memory. This multi-stage approach significantly complicates detection and analysis efforts.

Havoc Framework: The Ultimate C2 Weapon

The final payload deployed in these attacks is the open-source command-and-control framework known as Havoc. This choice demonstrates the group’s preference for legitimate, trusted infrastructure to execute targeted attacks while maintaining operational clandestinity. Havoc provides the attackers with extensive capabilities for data exfiltration, command execution, and persistent access.

Adaptive Tactics: From WinRAR to Telegram RAT

The campaign demonstrates remarkable adaptability. While early iterations in March 2025 utilized ZIP files containing Windows shortcuts (LNK) and batch (BAT) files to decrypt and execute the Amaranth Loader, later campaigns showed significant evolution in tactics.

In a September 2025 campaign targeting Indonesia, threat actors distributed password-protected RAR archives from Dropbox containing a fully functional remote access trojan (RAT) codenamed TGAmaranth RAT. This variant leverages a hard-coded Telegram bot for command and control, showcasing the group’s ability to pivot between different communication channels based on operational requirements.

Technical Sophistication: Anti-Analysis and Anti-Detection Measures

The malware implements comprehensive anti-debugging and anti-antivirus techniques to resist analysis and detection. The RAT supports an extensive command set including process enumeration, screenshot capture, shell command execution, file download, and file upload capabilities.

APT41 Connections: Shared Resources and Techniques

Amaranth-Dragon’s links to APT41 stem from significant overlaps in malware arsenal, suggesting possible connections or shared resources between the two clusters. Chinese threat actors are known for sharing tools, techniques, and infrastructure, making such connections unsurprising but nonetheless concerning.

Check Point researchers note that the development style, including creating new threads within export functions to execute malicious code, closely mirrors established APT41 practices. Compilation timestamps, campaign timing, and infrastructure management all point to a disciplined, well-resourced team operating in the UTC+8 (China Standard Time) zone.

Mustang Panda’s Parallel Campaign: PlugX Diplomacy

Simultaneously, another Chinese nation-state group tracked as Mustang Panda has been orchestrating its own sophisticated campaign dubbed PlugX Diplomacy. This operation has targeted officials involved in diplomacy, elections, and international coordination across multiple regions between December 2025 and mid-January 2026.

Rather than exploiting software vulnerabilities, Mustang Panda relied on impersonation and trust, luring victims into opening files that appeared to be U.S.-linked diplomatic summaries or policy documents. The operation deployed a customized variant of PlugX called DOPLUGS, which has been detected in the wild since late December 2022.

The Future of Cyber Espionage: Living-Off-The-Land Tactics

Both campaigns demonstrate the evolving nature of cyber espionage, with threat actors increasingly relying on legitimate executables, trusted cloud platforms, and living-off-the-land binaries (LOLBins) to maintain stealth and persistence. The correlation between actual diplomatic events and the timing of detected lures suggests that analogous campaigns are likely to persist as geopolitical developments unfold.

Conclusion: An Escalating Cyber Cold War

The emergence of Amaranth-Dragon and Mustang Panda’s parallel operations represents a significant escalation in the cyber cold war between China and its regional rivals. These campaigns demonstrate not only technical sophistication but also strategic patience and geopolitical awareness that make them particularly dangerous.

Entities operating in diplomatic, governmental, and policy-oriented sectors must now regard malicious LNK distribution methods and DLL search-order hijacking via legitimate executables as persistent, high-priority threats rather than isolated or fleeting tactics. The cyber battlefield has expanded, and Southeast Asia finds itself at the center of a new era of digital espionage warfare.

tags

ChineseAPT #CyberEspionage #WinRARExploit #SoutheastAsia #ZeroDay #APT41 #AmaranthDragon #MustangPanda #PlugXDiplomacy #CyberWarfare #GeopoliticalHacking #StateSponsoredCybercrime #DigitalEspionage #CyberColdWar #AdvancedPersistentThreat

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