GuLoader is a sophisticated malware loader first identified in 2019, primarily used by cybercriminals to deliver additional malicious payloads, such as remote access trojans (RATs), info-stealers, and ransomware, onto compromised systems. Typically distributed via phishing emails containing malicious attachments or links, GuLoader employs advanced evasion techniques like shellcode encryption and anti-analysis methods to bypass security defenses. Once executed, it connects to remote servers to download and execute further malware, making it a favored tool in multi-stage cyberattacks. Its modularity and persistent updates have enabled it to remain effective against modern security solutions.