Threats Tagged 'javascript loader'

A long-running campaign compromised the QuickFox VPN application, primarily used by Chinese users to access Chinese resources and improve gaming experiences. Active since August 2025, the attack involved trojanized Windows installers (versions 3.0.51.0 through 3.59.5) that deployed malicious JavaScript through modified Electron renderer HTML files. The JavaScript loader fingerprinted victim endpoints using process-based guardrails, checking for specific applications including administrative tools, cryptocurrency wallets, and Chinese translation software while avoiding Steam users. Successfully profiled targets received an FDMTP implant through DLL sideloading techniques using legitimate Microsoft Azure binaries. The infrastructure demonstrates active development with multiple staging domains masquerading as legitimate services. QuickFox removed malicious components from version 3.59.6 following responsible disclosure. Technical overlaps suggest possible connections to Twill Typhoon, though attribution remain

A new variant of the LOTUSLITE backdoor, version 1.1, has been identified targeting India's banking sector and South Korean diplomatic circles. The backdoor is delivered via DLL sideloading using legitimate Microsoft-signed executables and initially through CHM files containing malicious JavaScript. It communicates with dynamic DNS-based command-and-control servers over HTTPS, supporting remote shell access, file operations and session management. Code-level analysis reveals direct lineage to LOTUSLITE v1.0, including identical command structures, shared persistence mechanisms, and residual exports from the original codebase. The campaign demonstrates incremental improvements including updated magic values, API resolution techniques, and delivery mechanisms evolving from CHM-based to JavaScript loaders to DLL sideloading. Infrastructure hosted under Dynu Systems shows continuity with previous operations.

MediumMalwareUnited StatesBritish Indian Ocean TerritoryIndia#espionage#chm files#backdoor