Description

Modern threat actors are increasingly utilizing Fully Undetectable crypters in order to circumvent conventional anti-virus and endpoint detection programs. In essence, a crypter tool can be used by the attackers to cloak the malicious payload that can execute without being detected by any system during either delivery or execution. Moreover, the availability of the service within the underground world has made cyber attacks easier to launch. A FUD crypter refers to the tool created especially to obfuscate malware through encrypting, packing, and code mutation techniques. After encrypting malware with such a tool, it becomes unrecognizable to various security software since its signature changes once it is processed using such applications. These tools employ several encryption algorithms and methods, including multi-layered AES and XOR encryption coupled with in-memory execution. Typically, crypted files must pass multiple testing procedures against different antivirus programs in order to ensure that they are not detectable. Additionally, advanced versions have other features that make them anti-analysis. For example, some of the features include anti-debugging, anti-VM, and sandbox evasion techniques, among others. Moreover, they are capable of changing their structures through polymorphism. These crypters are widely distributed via dark web marketplaces and hacking forums, often offered as subscription-based services. Their accessibility enables even low-skilled attackers to execute sophisticated campaigns, contributing to the rapid expansion of the cybercrime ecosystem.