Malware Analysis Report - LockBit Ransomware v4.0

In this blog post, I’m going over my analysis for the latest variant of LockBit ransomware - version 4.0. Throughout this blog, I’ll walk through all the malicious functionalities discovered, complete with explanations and IDA screenshots to show my reverse engineering process step by step. This new version of LockBit 4.0 implements a hybrid-cryptography approach, combining Curve25519 with XChaCha20 for its file encryption scheme.

This version shares similarities with the older LockBit Green variant that is derived from Conti ransomware. While the multi-threading architecture seems more streamlined than previous versions, it still delivers an encryption speed that outpaces most other ransomware families.

As always, LockBit is still my most favorite malware to look at, and I certainly enjoyed doing a deep dive to understand how this version works.