GuLoader is a highly obfuscated malware-as-a-service downloader that has evolved since 2019 to deliver secondary payloads such as RATs and information stealers. It employs polymorphic code for dynamic constant construction, exception-based control flow obfuscation using five distinct CPU exception types, encrypted strings with stack-based decryption, and modified DJB2 API hashing. Payloads are hosted on trusted cloud platforms (Google Drive, OneDrive) to evade reputation-based detection, and the malware continues to receive updates increasing analysis complexity.
exception-based control flow
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GuLoader Malware Obfuscation Techniques Analyzed