GuLoader is an advanced downloader written in shellcode. It’s used by criminals to distribute other malware, notably trojans, on a large scale. It’s infamous for using anti-detection and anti-analysis capabilities.

A loader is malicious software that infiltrates devices to deliver malicious payloads. This malware is capable of infecting victims’ computers, analyzing their system information, and installing other types of threats, such as trojans or stealers. Criminals usually deliver loaders through phishing emails and links by relying on social engineering to trick users into downloading and running their executables. Loaders employ advanced evasion and persistence tactics to avoid detection.

Trojans are a group of malicious programs distinguished by their ability to masquerade as benign software. Depending on their type, trojans possess a variety of capabilities, ranging from maintaining full remote control over the victim’s machine to stealing data and files, as well as dropping other malware. At the same time, the main functionality of each trojan family can differ significantly depending on its type. The most common trojan infection chain starts with a phishing email.