Tech Optimizer
February 10, 2026
GuLoader, also known as CloudEye, is a downloader malware that has been active since late 2019, primarily used to fetch and install secondary malware like Remote Access Trojans (RATs) and information stealers. It employs legitimate cloud services such as Google Drive and Microsoft OneDrive to host its malicious payloads, allowing it to evade detection by security tools. GuLoader utilizes advanced techniques including polymorphic code, which alters its appearance to avoid static detection signatures, and exception-based control flow to confuse analysis tools. Over the years, GuLoader has refined its tactics, including the use of software breakpoints and various exception types to redirect its operations. It also employs dynamic XOR encryption to obfuscate internal data, making it difficult for analysts to extract URLs. The malware's continuous evolution poses ongoing challenges for security researchers.
Indicators of Compromise (IOCs) include specific hash values for different versions of GuLoader from 2022 to 2024.
