A sophisticated malware campaign has been uncovered, attributed to the Russian threat actor COLDRIVER, also known as Star Blizzard or Callisto. The malware, named LOSTKEYS, has been observed targeting diplomatic institutions, defense contractors, and critical infrastructure across Europe and North America. This campaign, which began in early 2025, is specifically designed for data exfiltration, with a primary focus on stealing credentials, sensitive documents, and communications. The attackers employ spear-phishing emails with malicious document attachments, exploiting previously undisclosed vulnerabilities in widely-used office productivity software.
Upon opening the malicious attachments, a multi-stage infection process begins, allowing the malware to establish persistence on the victim’s system while evading conventional security measures. The emails, which appear legitimate and often masquerade as trusted communications from government agencies or partners, serve as the initial vector for the attack. The malware’s complex obfuscation techniques and sophisticated command-and-control infrastructure complicate detection and attribution efforts. Google Threat Intelligence researchers uncovered unusual data transfer patterns that led to the identification of this campaign.
Once the malware infiltrates the system, it deploys a PowerShell downloader that retrieves the main LOSTKEYS payload.
The infection process uses obfuscated VBA macros to launch the attack, which ultimately enables the malware to maintain persistence by making registry modifications and scheduling tasks on the infected machine. To avoid detection, LOSTKEYS conducts environment checks to identify security tools and evade detection where necessary. It also uses encrypted communication channels that mimic legitimate HTTPS traffic, making network monitoring and detection extremely difficult.
The LOSTKEYS malware campaign has had a significant impact, with affected organizations reporting theft of intellectual property and unauthorized access to sensitive communications.
The malware’s stealthy operation means many victims remain unaware of its presence for long periods, allowing continuous data harvesting. Security agencies worldwide have issued warnings about this evolving threat, which represents a significant escalation in COLDRIVER’s tactics and capabilities.
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