Threats Tagged 'guloader'

This analysis examines new obfuscation techniques employed by Gremlin stealer malware to conceal malicious payloads within embedded resources. A variant protected by sophisticated commercial packing utility uses instruction virtualization, transforming code into custom bytecode executed by a private virtual machine. The malware siphons sensitive information including payment card details, browser cookies, session tokens, cryptocurrency wallet data, and FTP/VPN credentials from compromised systems. It exfiltrates data to attacker-controlled servers at hxxp[:]194.87.92[.]109 for potential publication or sale. Recent iterations incorporate expanded Discord token extraction, active financial fraud through crypto clipper functionality that replaces cryptocurrency wallet addresses in real-time, and WebSocket-based session hijacking to bypass modern cookie protections. The malware employs advanced anti-analysis techniques including XOR-encoded payloads in .NET resource sections, identifier renaming, string encryp...

GuLoader, a malware downloader active since 2019, primarily delivers RATs and information stealers. It employs sophisticated anti-analysis techniques, including polymorphic code for dynamic constant construction and complex exception-based control flow obfuscation. The malware has evolved to handle multiple exception types, making tracing its execution flow challenging. GuLoader uses dynamic hashing, encrypted strings, and stack-based string encryption to conceal critical information. It often hosts payloads on trusted cloud services to bypass reputation-based detection. The malware's consistent development and updating of anti-analysis techniques suggest it will remain a significant threat in the future.

MediumMalwareGermanyUnited KingdomFrance+4#anti-analysis#cloudeye#guloader

ASEC discovered Guloader malware being distributed through phishing emails masquerading as employee performance reports. The emails, claiming to be about October 2025 performance, contain a RAR file with an NSIS executable named 'staff record pdf.exe'. This file is actually Guloader malware, which downloads and executes shellcode from a Google Drive URL. The final payload is Remcos RAT, enabling threat actors to perform various malicious remote control activities, including keylogging, screenshot capture, webcam and microphone control, and browser data extraction. The attackers are increasingly using legitimate platforms as C2 servers, making detection more challenging. Users are advised to exercise caution when opening emails from unknown sources and to change passwords regularly to prevent secondary damage.

MediumMalwareGermanyFranceUnited Kingdom+4#remcos rat#infostealer#shellcode