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Jacob Santos

Jacob Santos

Threat Hunter, Researcher and Builder

Sr. Threat Researcher | Trend AI
17
Articles
14
Threads
10+
Tools
10+
Talks
Published Research

Published Research

Threat research articles and microstories on emerging campaigns.

Published threat research articles and X/Twitter microstories. Much of my work is internal threat intelligence under TLP:AMBER.

18 Blog Articles 14 Microstories 32 Total
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Web Shells, Tunnels, and Ransomware: Dissecting a Warlock Attack
New Mar 2026

Web Shells, Tunnels, and Ransomware: Dissecting a Warlock Attack

Deep-dive analysis of Warlock (Water Manaul) ransomware operations revealing new TTPs including persistent BYOVD techniques, TightVNC and Yuze remote access tools, and 15-day dwell time before LockBit-derived ransomware deployment.

RansomwareDefense EvasionAPT
Five New Rust-Based Ransomware Families Identified
New Thread Feb 2026

Five New Rust-Based Ransomware Families Identified

Thread analyzing five distinct ransomware groups written in Rust identified in early December 2025, signaling an accelerated shift in how threat actors build and scale attacks.

RansomwareRust
Agenda Ransomware: Continued Linux-on-Windows Campaign
New Thread Feb 2026

Agenda Ransomware: Continued Linux-on-Windows Campaign

Thread on a new Agenda ransomware campaign continuing the group's use of Linux binaries on Windows systems, with new techniques and tooling building on earlier 2025 attacks.

RansomwareCross-Platform
PureRAT Campaign Targets Job Seekers, Abuses Foxit PDF Reader for DLL Side-loading
Dec 2025

PureRAT Campaign Targets Job Seekers, Abuses Foxit PDF Reader for DLL Side-loading

Uncovered PureRAT targeting job seekers using renamed Foxit PDF Reader for DLL side-loading and Python-based shellcode loaders.

RATSocial EngineeringDLL Sideloading
Agenda Ransomware Deploys Linux Variant on Windows Systems Through Remote Management Tools and BYOVD Techniques
Oct 2025

Agenda Ransomware Deploys Linux Variant on Windows Systems Through Remote Management Tools and BYOVD Techniques

Discovered Agenda ransomware deploying Linux variants on Windows systems via remote management tools and BYOVD techniques for cross-platform evasion.

RansomwareCross-PlatformDefense Evasion
Self-Propagating Malware Spreading Via WhatsApp, Targets Brazilian Users
Oct 2025

Self-Propagating Malware Spreading Via WhatsApp, Targets Brazilian Users

Identified an active campaign spreading self-propagating malware via WhatsApp ZIP attachments, targeting Brazilian users with persistence and account hijacking.

RATSocial Engineering
Unmasking The Gentlemen Ransomware: Tactics, Techniques, and Procedures Revealed
Sep 2025

Unmasking The Gentlemen Ransomware: Tactics, Techniques, and Procedures Revealed

Analysis of a new ransomware group with adaptive defense evasion — custom-patching anti-AV tools mid-attack based on target recon.

RansomwareBYOVDDefense Evasion
New LockBit 5.0 Targets Windows, Linux, ESXi
Sep 2025

New LockBit 5.0 Targets Windows, Linux, ESXi

Technical analysis of LockBit 5.0 — cross-platform ransomware with heavy obfuscation, anti-analysis, and geopolitical safeguards.

RansomwareCross-PlatformLockBit
New Ransomware Charon Uses Earth Baxia APT Techniques to Target Enterprises
Aug 2025

New Ransomware Charon Uses Earth Baxia APT Techniques to Target Enterprises

Discovered Charon ransomware using APT-grade techniques — DLL sideloading via Edge.exe, hybrid Curve25519/ChaCha20 encryption.

RansomwareAPT CrossoverDLL Sideloading
Crypto24 Ransomware Group Blends Legitimate Tools with Custom Malware for Stealth Attacks
Aug 2025

Crypto24 Ransomware Group Blends Legitimate Tools with Custom Malware for Stealth Attacks

Analyzed Crypto24 ransomware group's technique of blending legitimate tools with custom malware to bypass EDR and security technologies.

RansomwareDefense Evasion
Chaos Ransomware Leverages Advanced Anti-EDR Techniques
Thread Sep 2025

Chaos Ransomware Leverages Advanced Anti-EDR Techniques

Thread analyzing the Chaos ransomware campaign leveraging malicious DLL sideloading and kernel-level driver deployment for broad defense evasion against EDR solutions.

RansomwareEDR EvasionDefense Evasion
Warlock: From SharePoint Vulnerability Exploit to Enterprise Ransomware
Aug 2025

Warlock: From SharePoint Vulnerability Exploit to Enterprise Ransomware

Traced the Warlock ransomware campaign from initial SharePoint vulnerability exploit through lateral movement to enterprise-wide encryption.

RansomwareDefense Evasion
Nitrogen Ransomware: Fake Updates and Malicious Browser Extensions
Thread Sep 2025

Nitrogen Ransomware: Fake Updates and Malicious Browser Extensions

Thread on the rapidly evolving Nitrogen ransomware group using social engineering via fake updates and malicious browser extensions for initial access.

RansomwareSocial Engineering
CVE-2025-53770 & CVE-2025-53771: SharePoint Zero-Days at Pwn2Own
Thread Jul 2025

CVE-2025-53770 & CVE-2025-53771: SharePoint Zero-Days at Pwn2Own

Thread on CVE-2025-53770 and CVE-2025-53771 — vulnerabilities in on-premise Microsoft SharePoint servers discovered at Pwn2Own Berlin, with TippingPoint customers protected since May.

VulnerabilitySharePointZero-Day
Charon Ransomware: Advanced Breach and Lateral Movement
Thread Aug 2025

Charon Ransomware: Advanced Breach and Lateral Movement

Thread exposing the newly identified Charon ransomware and its advanced methods for breaching and spreading within organizations.

RansomwareAPT Crossover
Proactive Security for CVE-2025-53770 and CVE-2025-53771 SharePoint Attacks
Jul 2025

Proactive Security for CVE-2025-53770 and CVE-2025-53771 SharePoint Attacks

Provided proactive security analysis of CVE-2025-53770 and CVE-2025-53771 — SharePoint vulnerabilities enabling unauthenticated remote code execution.

Defense EvasionRed Team Tools
Revisiting UNC3886 Tactics to Defend Against Present Risk
Jul 2025

Revisiting UNC3886 Tactics to Defend Against Present Risk

Revisiting the tactics of UNC3886, a China-nexus threat actor targeting network edge devices and virtualization infrastructure.

APTChina-NexusEspionage
Agenda Ransomware Exploits MeshAgent and WSL for Cross-Platform Attacks
Thread Jul 2025

Agenda Ransomware Exploits MeshAgent and WSL for Cross-Platform Attacks

Thread on Agenda ransomware exploiting MeshAgent and Windows Subsystem for Linux (WSL) to deploy Linux payloads on Windows systems, raising the bar for cross-platform sophistication.

RansomwareCross-PlatformDefense Evasion
Agenda Ransomware Group Adds SmokeLoader and NETXLOADER to Their Arsenal
May 2025

Agenda Ransomware Group Adds SmokeLoader and NETXLOADER to Their Arsenal

Uncovered Agenda ransomware group adopting SmokeLoader and a new loader named NETXLOADER for improved delivery and evasion.

RansomwareDefense EvasionCross-Platform
CrazyHunter Campaign Targets Taiwanese Critical Sectors
Apr 2025

CrazyHunter Campaign Targets Taiwanese Critical Sectors

Identified CrazyHunter targeting Taiwanese healthcare and education using 80% open-source tooling and BYOVD attacks.

RansomwareTaiwanBYOVD
AI-Assisted Fake GitHub Repositories Fuel SmartLoader and LummaStealer Distribution
Mar 2025

AI-Assisted Fake GitHub Repositories Fuel SmartLoader and LummaStealer Distribution

Uncovered AI-generated fake GitHub repositories distributing SmartLoader and LummaStealer through convincing but malicious code projects.

Social EngineeringRATDefense Evasion
Agenda Ransomware Adopts TrueSightKiller for EDR Evasion
Thread Mar 2025

Agenda Ransomware Adopts TrueSightKiller for EDR Evasion

Thread detailing how the Agenda ransomware group incorporated the open-source TrueSightKiller tool to disable antivirus and EDR systems via BYOVD techniques.

RansomwareBYOVDEDR Evasion
SmokeLoader Delivers W3CryptoLocker via Steganography
Thread Mar 2025

SmokeLoader Delivers W3CryptoLocker via Steganography

Thread analyzing SmokeLoader's use of steganography techniques to deliver W3CryptoLocker ransomware payloads while evading detection mechanisms.

RansomwareDefense EvasionSteganography
Morpheus Ransomware Emerges with New Data-Leak Site
Thread Jan 2025

Morpheus Ransomware Emerges with New Data-Leak Site

Thread on the emergence of the Morpheus ransomware group and its new data-leak site, with early victims including an Australian pharmaceutical firm and a German electronics company.

RansomwareData Exfiltration
Agenda Ransomware Variant Uses Obfuscated .NET Loader with Reflective Loading
Thread Nov 2024

Agenda Ransomware Variant Uses Obfuscated .NET Loader with Reflective Loading

Thread on an Agenda ransomware variant leveraging a highly obfuscated .NET loader using Reflective Loading and .NET Reactor for defense evasion.

RansomwareDefense Evasion.NET
Silent Threat: Red Team Tool EDRSilencer Disrupting Endpoint Security Solutions
Oct 2024

Silent Threat: Red Team Tool EDRSilencer Disrupting Endpoint Security Solutions

First to document EDRSilencer weaponized in the wild — a red team tool using Windows Filtering Platform to blind EDR solutions.

Red Team ToolsEDR EvasionWFP
MedusaLocker's Sophisticated Three-Pronged Attack Strategy
Thread Oct 2024

MedusaLocker's Sophisticated Three-Pronged Attack Strategy

Thread detailing a sophisticated new three-pronged attack strategy employed by MedusaLocker ransomware threat actors identified by the Threat Hunting team.

RansomwareDefense Evasion
Play Ransomware's First Linux Variant Targets ESXi
Thread Jun 2024

Play Ransomware's First Linux Variant Targets ESXi

Thread announcing the discovery of a new Linux variant of Play ransomware targeting ESXi environments, marking an expansion in the group's range and impact.

RansomwareCross-Platform
Play Ransomware Group's New Linux Variant Targets ESXi, Shows Ties With Prolific Puma
Jul 2024

Play Ransomware Group's New Linux Variant Targets ESXi, Shows Ties With Prolific Puma

First discovery of Play ransomware's Linux variant targeting ESXi, with infrastructure ties to Prolific Puma link-shortening service.

RansomwareCross-PlatformDefense Evasion
Multistage RA World Ransomware Uses Anti-AV Tactics, Exploits GPO
Mar 2024

Multistage RA World Ransomware Uses Anti-AV Tactics, Exploits GPO

Analyzed RA World using GPO-distributed payloads, Safe Mode abuse for defense evasion, and Babuk-derived encryption.

RansomwareGPO AbuseSafe Mode
Werewolves: Investigating a New Ransomware Player
Thread Jan 2024

Werewolves: Investigating a New Ransomware Player

Thread investigating the newly identified Werewolves ransomware group after an external researcher's blog post caught the Threat Hunting team's attention.

Ransomware
Cerber Ransomware Exploits Atlassian Confluence Vulnerability CVE-2023-22518
Nov 2023

Cerber Ransomware Exploits Atlassian Confluence Vulnerability CVE-2023-22518

Documented Cerber ransomware operators rapidly weaponizing CVE-2023-22518 in Atlassian Confluence for initial access and encryption deployment.

RansomwareDefense Evasion