NailaoLocker ransomware is a new threat that targeted European healthcare organizations from June to October 2024. Orange Cyberdefense CERT uncovered a malware campaign, tracked as The Green Nailao campaign, that targeted European organizations, including healthcare, in late 2024, using ShadowPad, PlugX, and the previously undocumented NailaoLocker ransomware. The Orange Cyberdefense CERT investigated four attackers with […] Execution flow of NailaoLoader and NailaoLocker – Source Orange CERT The locker checks if sensapi.dll is loaded before removing it from memory and deleting it from disk. The malicious code creates the mutex “Global\lockv7”. NailaoLocker ransomware is written in C++, the researchers said that the malware is not sophisticated and is poorly designed. The NailaoLocker ransomware does not scan network shares, cannot stop services or processes that could prevent the encryption of certain important files, and does not control if it is being debugged. The ransomware appends the “.locked” extension to the filenames of encrypted files. The malware uses asymmetric encryption algorithm AES-256-CTR. It drops a ransom note in: “%ALLUSERPROFILE%unlock_please_view_this_file_unlock_please_view_this_file_unlock_please_view_this_file_unlock_please_view_this_file_unlock_please_view_this_file_unlock_please_view_this_file_unlock_please.html” The ransom note directs victims to a ProtonMail address but does not mention data theft, which is unusual for modern ransomware attacks. Operators accept ransom payments in Bitcoin. Orange Cyberdefense CERT linked the attacks to China-linked APTs, but pointed out that there’s not enough evidence to attribute them to specific groups. Green Nailao aligns with Chinese intrusion tactics, using ShadowPad and DLL side-loading. Though similar to past espionage campaigns, its ransomware use is unusual. Possible motives include a false-flag distraction, dual-purpose financial and espionage attacks, or an independent actor leveraging state tools for profit. Despite overlaps with known groups, Green Nailao remains unattributed. “The targeting of healthcare-related entities by state-aligned groups, including from China, is not new. As recalled in the French national cybersecurity agency’s (ANSSI) Threat landscape for the healthcare sector, while such campaigns can sometimes be conducted opportunistically, they often allow threat groups to gain access to information systems that can be used later to conduct other offensive operations.” concludes the report. “Researchers from Mandiant for instance observed APT41 targeting US pharmaceutical entities in early 2020, meanwhile APT18 or APT10 have been historically tied to even older breaches affecting this vertical.” Follow me on Twitter: @securityaffairs and Facebook and Mastodon Pierluigi Paganini (SecurityAffairs hacking, ransomware)
Published: 2025-02-20T15:47:59