Posts Written ByJason Reaves

Jason Reaves

Jason Reaves is a Principal Threat Researcher at SentinelLabs who specializes in malware reverse-engineering. He has spent the majority of his career tracking threats in the Crimeware domain, including reverse-engineering data structures and algorithms found in malware in order to create automated frameworks for harvesting configuration and botnet data. Previously, he worked as a software developer and unix administrator in the financial industry and also spent six years in the U.S. Army. Jason holds multiple certifications related to reverse-engineering and application exploitation and has published numerous papers on topics such as writing malware scripts pretending to be a bot, unpackers, configuration data harvesters and covert channel utilities. He enjoys long walks in IDA and staring at RFCs for hours.

Enter the Maze: Demystifying an Affiliate Involved in Maze (SNOW)

SentinelLabs profiles an affiliate involved with Maze ransomware and details the actor’s involvement with other crimeware families, including TrickBot.

Security Research

Breaking EvilQuest | Reversing A Custom macOS Ransomware File Encryption Routine

A new macOS ransomware threat uses a custom file encryption routine not based on public key encryption. Jason Reaves shows how we broke it.

Valak Malware and the Connection to Gozi Loader ConfCrew

Valak uses a multi-stage, script-based malware that hijacks email replies and embeds malicious URLs or attachments to infect devices with fileless scripts.

Security Research

Sarwent Malware Continues to Evolve With Updated Command Functions

Sarwent has received little attention from researchers, but this backdoor malware is still being actively developed, with new commands and a focus on RDP.

Deep Dive Into TrickBot Executor Module “mexec”: Reversing the Dropper Variant

Continuing our earlier analysis of the TrickBot Executor Module “mexec”, we take a look at the dropper variant and reveal how it carries its payload onboard.

Deep Dive Into TrickBot Executor Module “mexec”: Hidden “Anchor” Bot Nexus Operations

New “mexec” module delivers tertiary malware and allows TrickBot to pivot within a network, deploy a variety of payloads and evade common detection methods.

Advanced Persistent Threat

Breaking TA505’s Crypter with an SMT Solver

TA505 threat group use a crypter common to Clop/CryptoMix ransomware and others. We tear it down with a new unpacker utilizing SMT.

Revealing the Trick | A Deep Dive into TrickLoader Obfuscation

TrickBot’s loader has received much less attention than other components of the malware. Jason Reaves shows how to reverse engineer the TrickLoader function.

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