messaging services

The REF6598 intrusion set has revealed a Remote Access Trojan (RAT) named PHANTOMPULSE, which is distributed via malicious Obsidian plugins. It uses advanced evasion techniques, including a blockchain-based command and control (C2) channel and a public User Account Control (UAC) bypass to infiltrate Windows systems. The malware disables security measures like the Antimalware Scan Interface (AMSI) and Windows Lockdown Policy (WLDP) through a hardware-breakpoint technique, allowing it to avoid detection by signature-based memory scanners. PHANTOMPULSE hides its core files in encrypted registry blobs and creates scheduled tasks that appear as .NET Framework updates. Its decentralized C2 framework queries public blockchains for operational data, but it lacks sender authentication, which can be exploited by defenders. The malware inventories the system for antivirus software and targets high-value applications. It employs a UAC bypass technique called “schuac” to gain elevated permissions. Analysts attribute this campaign to DPRK-aligned threat actors, particularly the BlueNoroff group, due to its focus on cryptocurrency wallets and blockchain exploitation. Defenders can identify new infrastructure by searching blockchain ledgers for a specific hex signature associated with the malware's C2 encryption routine.