Malicious Developer Extensions Power Sophisticated “Evelyn” Malware Campaign Stealing Credentials and Crypto Assets

In early December 2025, a highly targeted malware campaign was identified that focused on compromising software developers through malicious extensions distributed via trusted development tooling ecosystems. The operation, tracked internally as Evelyn Stealer, represents a mature, multi-stage credential theft campaign designed to exploit developer trust, evade modern detection mechanisms, and extract high-value data including credentials, cryptocurrency assets, and system intelligence.

Unlike opportunistic malware, this campaign demonstrates deliberate targeting, operational discipline, and a deep understanding of Windows internals, browser security architecture, and developer workflows. The attackers treated the developer environment itself as the delivery mechanism, turning trusted extensions into the initial infection vector.


Target Profile and Impacted Sectors

Primary Targets

  • Individual software developers
  • Open-source contributors
  • Freelance developers
  • Blockchain and Web3 developers
  • DevOps engineers
  • Developers with access to CI/CD pipelines and cloud infrastructure

Impacted Industries

  • Software development
  • Blockchain and cryptocurrency
  • FinTech
  • SaaS providers
  • Cloud service operators
  • Game development studios
  • AI and machine learning startups

Organizational Risk

A single compromised developer workstation can lead to:

  • Theft of source code and intellectual property
  • Compromise of private repositories
  • Abuse of cloud credentials and API tokens
  • Supply-chain attacks via poisoned commits or packages
  • Direct cryptocurrency theft

Attack Chain Overview

The Evelyn Stealer campaign uses a three-stage architecture:

  1. Initial access via malicious code editor extension
  2. Downloader masquerading as a legitimate DLL
  3. Process hollowing injector
  4. Final info-stealer payload

Each stage is purpose-built and minimizes exposure, ensuring stealth and persistence.


Image Source : trendmicro

Stage 1: Initial Access and Downloader Execution

Delivery Vector

The infection begins when a developer installs a weaponized extension disguised as a legitimate productivity or development aid. Once installed, the extension drops a malicious DLL into the environment.

Masquerading Technique

The DLL is named and structured to impersonate a legitimate Lightshot dependency. This allows it to be side-loaded when the legitimate executable launches.

File Details

File NameSHA-256Type
Lightshot.dll369479bd9a248c9448705c222d81ff1a0143343a138fc38fc0ea00f54fcc1598DLL

Execution Mechanics

  • Loaded automatically due to Windows DLL search order
  • Exposes legitimate-looking exported functions to avoid suspicion
  • Executes payload immediately upon load
  • Uses a singleton execution pattern
  • Creates a mutex to prevent multiple instances

Persistence and Control

  • Mutex ensures one active instance per system
  • Execution occurs within the trusted process context

Payload Delivery

The DLL launches a hidden PowerShell process that:

  • Downloads the second-stage payload
  • Writes it to %LOCALAPPDATA%\Temp
  • Renames it as runtime.exe
  • Executes it silently

Stage 2: Injector and Process Hollowing

File Details

File NameSHA-256Type
iknowyou.model92af258d13494f208ccf76f53a36f288060543f02ed438531e0675b85da00430EXE

Purpose

This stage acts as a process hollowing injector, responsible for decrypting and injecting the final payload into a legitimate Windows process.

Target Process

  • grpconv.exe (a trusted Windows utility)

Execution Flow

  1. Dynamically resolves Windows APIs
  2. Creates grpconv.exe in suspended mode
  3. Decrypts embedded payload using AES-256-CBC
  4. Injects decrypted payload into suspended process
  5. Resumes execution

Cryptographic Details

  • AES Key (32 bytes)
    2e649f6145f55988b920ff5a445e63aae29c80495b830e0d8bb4b3fff4b1f6f4
  • IV (16 bytes)
    5c507b22e9814428c5f2b1ef213c5c4a

This ensures that the final payload is never stored unencrypted on disk.


Stage 3: Final Payload – Evelyn Stealer

File Details

File NameSHA-256Type
EvelynStealer.exeaba7133f975a0788dd2728b4bbb1d7d948e50571a033a1e8f47a2691e98600c5EXE

Anti-Analysis and Evasion Techniques

Before activating malicious functionality, Evelyn Stealer performs extensive environment checks:

Virtual Machine Detection

  • GPU fingerprinting (VMware, VirtualBox, Hyper-V, QEMU, VirtIO)
  • Disk size checks (< 60 GB flagged)
  • Hostname analysis
  • VM-related process enumeration
  • Registry inspection for virtual hardware identifiers

Sandbox and Research Detection

  • Debugger detection
  • RDP session checks
  • Hyper-V artifacts
  • Timing anomalies

If analysis conditions are detected, execution is halted.


Data Collection and Theft Capabilities

Workspace Setup

  • Creates a dedicated directory under %APPDATA%
  • Organizes stolen data by category

Browser Credential Theft

  • Terminates active browser processes
  • Recovers existing browser data
  • Uses DLL injection to access decrypted credentials in memory

Browser Injection Component

  • abe_decrypt.dll

Acquisition Priority

  1. TEMP directory
  2. FTP server download
  3. Local directory fallback

DLL Hash

74e43a0175179a0a04361faaaaf05eb1e6b84adca69e4f446ef82c0a5d1923d5

Browser Launch Flags

The malware launches browsers with stealth-oriented flags:

  • --headless=new
  • --disable-gpu
  • --no-sandbox
  • --disable-extensions
  • --disable-logging
  • --silent-launch
  • --no-first-run
  • --disable-popup-blocking
  • --window-position=-10000,-10000
  • --window-size=1,1

This allows credential extraction without user awareness.


Additional Data Harvested

  • System details (OS, hardware, installed software)
  • Running processes
  • VPN configurations
  • Clipboard contents
  • Wi-Fi credentials
  • Sensitive files
  • Cryptocurrency wallets (MetaMask, Phantom, Trust Wallet, others)
  • Desktop screenshots

Data Packaging and Exfiltration

Archive Naming Convention

The stolen data is compressed into a ZIP file using a detailed identifier format:

COUNTRY-IP-USERNAME-OS-CRYPTO-PAYPAL-CRYPTO_SITES-RAM-GPU-METAMASK-PHANTOM-TRUSTWALLET-OTHER-TIMESTAMP.zip

Exfiltration Channel

  • FTP protocol
  • Custom authentication
  • Obfuscated transfer intervals

Command-and-Control Infrastructure

Known Network Indicators

IndicatorType
server09.mentality[.]cloudFTP Server
syn1112223334445556667778889990[.]orgHTTP Server

Indicators of Compromise (IoCs)

File Hashes

FileSHA-256
Lightshot.dll369479bd9a248c9448705c222d81ff1a0143343a138fc38fc0ea00f54fcc1598
iknowyou.model92af258d13494f208ccf76f53a36f288060543f02ed438531e0675b85da00430
EvelynStealer.exeaba7133f975a0788dd2728b4bbb1d7d948e50571a033a1e8f47a2691e98600c5
abe_decrypt.dll74e43a0175179a0a04361faaaaf05eb1e6b84adca69e4f446ef82c0a5d1923d5

Strategic Assessment

This campaign reflects a shift toward developer-centric threat models. Instead of mass infection, the attackers pursued quality over quantity, targeting individuals whose access could yield disproportionate impact.

The use of trusted tooling, staged loaders, encrypted payloads, memory-only credential access, and disciplined operational security indicates a threat actor with strong technical expertise and long-term objectives.


Defensive Considerations

Organizations should:

  • Enforce strict extension allow-listing
  • Monitor DLL side-loading behavior
  • Restrict PowerShell abuse
  • Protect developer endpoints as high-value assets
  • Monitor FTP traffic from user workstations
  • Assume developer compromise as a supply-chain risk

Closing Thoughts

Evelyn Stealer is not just another info-stealer. It represents an evolution in attacker thinking, where developers are no longer collateral damage but primary entry points. As development environments grow more powerful and interconnected, attackers will continue to weaponize trust itself.

Defending against this class of threat requires rethinking how developer systems are secured, monitored, and treated within enterprise risk models.