A phishing campaign distributes the AgentTesla infostealer via emails pretending to be business proposals. The attached ZIP file contains a malicious executable disguised as a café management program with Chinese-language UI. The malware uses multi-stage obfuscation and .NET payload loading to ultimately deploy AgentTesla, which steals credentials, cookies, and contact information from browsers, email clients, FTP, and VPN applications. Stolen data is exfiltrated through FTP to a compromised server. The attack targets business users using social engineering and sophisticated loading techniques.
The Larva-24009 threat actor, also known as HeptaX, has been conducting phishing email campaigns since 2023, targeting Korean and global users to install malware. Active through 2026, the actor uses LNK files disguised as documents with topics like hospital surveys, blockchain, project proposals, and resumes to target enterprises. Upon execution, obfuscated PowerShell commands deploy backdoors and download additional scripts from command-and-control servers. The attack chain includes persistence mechanisms via Task Scheduler, remote access through QuasarRAT and UltraVNC, and information theft using NirSoft tools, custom keyloggers, and screenshot capabilities. The actor also creates backdoor RDP accounts and exfiltrates credentials, browser data, and user files. Version 2.1 of their Notifier malware utilizes Telegram API for status reporting. The campaigns demonstrate consistent tactics and infrastructure across multiple years of operation.
In March 2026, trojans represented 21% of attachment-based threats, while phishing attacks using fake pages dropped from 42% to 15% month-over-month. Script-based malware increased significantly, with HTML at 14% and JavaScript at 11%. Compressed files including ZIP (14%), RAR (8%), and 7Z (5%) were common distribution methods. Document-based threats utilized PDF (13%), XLS (5%), and DOCX (2%) files. Attackers impersonated courier services like FedEx and DHL, as well as financial institutions including Hana Bank and Woori Bank. Distribution methods included HTML scripts and PDF hyperlinks leading to credential-stealing pages. Notable malware families included RemcosRAT and AgentTesla, with command-and-control infrastructure utilizing Telegram API tokens and external mail servers for data exfiltration.