Blackstealer
Overview
Executive Summary
BlackStealer is a malicious Information Stealer (Info Stealer) Trojan designed to covertly exfiltrate sensitive data from compromised Windows systems. Unlike large botnets, BlackStealer functions as a precision data-harvesting tool, specifically targeting login credentials, cryptocurrency wallets, financial data, and session tokens to facilitate immediate financial fraud or to sell the stolen access to Initial Access Brokers (IABs).Infection Vector and Technical Capabilities
BlackStealer is typically distributed via spear-phishing campaigns (often disguised as invoices or shipping documents), bundled with cracked software on peer-to-peer networks, or deployed as a secondary payload by exploit kits. Once executed, BlackStealer operates silently to harvest data:- Credential Store Extraction: The primary function is the systematic extraction of saved passwords, cookies, and autofill data from the local databases of major web browsers (Chrome, Firefox, Edge, Opera).
- Application Targeting: It specifically targets the configuration files and local storage of desktop email clients (Outlook, Thunderbird), FTP clients (FileZilla), and messaging applications (Discord, Telegram) to steal authentication tokens.
- Cryptocurrency Wallet Theft: BlackStealer aggressively scans the file system for `wallet.dat` files and extensions associated with popular cryptocurrency wallets (Bitcoin Core, Electrum, Exodus).
- Data Exfiltration: The harvested data is compressed into an archive (often a ZIP file) and rapidly exfiltrated to the attacker's Command and Control (C2) server via HTTP/HTTPS POST requests or Telegram bots.
Threat Assessment
A BlackStealer infection is a critical security incident that immediately compromises user identity and access. The theft of corporate VPN/RDP credentials or session cookies allows attackers to bypass perimeter security, including Multi-Factor Authentication (MFA), potentially leading to a massive enterprise data breach or ransomware deployment.Incident Response and Remediation
- Immediate Endpoint Isolation: The highest priority is to disconnect the infected endpoint from the network to halt the active exfiltration of the data archive.
- Global Credential and Session Reset: It must be assumed that all passwords and session tokens present on the machine have been stolen. A mandatory, immediate reset of all associated credentials, and the revoking of all active web sessions, is absolutely required.
- Complete Re-imaging: To ensure no hidden persistence mechanisms or secondary backdoors remain, the compromised endpoint must undergo a complete bare-metal wipe and re-image from a trusted baseline.
Known aliases
Threat reports may refer to this family under multiple names:
MITRE ATT&CK Techniques
This family has been observed using the following ATT&CK techniques: T1555.003 T1005 T1114
Generated Detections (Boilerplate)
These YARA and Sigma rules are auto-generated based on the family name and aliases. They must be heavily tuned before deployment in a production environment.
YARA Rule
rule MALWARE_WIN_BLACKSTEALER {
meta:
description = "Detects Blackstealer (ransomware)"
author = "SystemHelpdesk Boilerplate Generator"
date = "2026-07-06"
strings:
$s1 = "blackstealer" ascii wide nocase
$s2 = "trojan.blackstealer" ascii wide nocase
$s3 = "infostealer.black" ascii wide nocase
$s4 = "win32/spy.stealer" ascii wide nocase
condition:
uint16(0) == 0x5a4d and any of them
}Sigma Rule
title: Suspicious Blackstealer Activity
id: 3964b5e2ec2cd3c44cea7add47fdfda2
status: experimental
description: Detects generic indicators of the blackstealer malware family.
logsource:
category: process_creation
product: windows
detection:
selection:
Image|endswith:
- '\cmd.exe'
- '\powershell.exe'
CommandLine|contains:
- "*blackstealer*"
- "*trojan.blackstealer*"
- "*infostealer.black*"
- "*win32/spy.stealer*"
condition: selection
level: mediumReferences & External Analysis
- Search "blackstealer" on VirusTotal (External Analysis)
Frequently Asked Questions
How do I remove the Blackstealer Ransomware from Windows?
Manual removal of Blackstealer is highly discouraged as it may leave persistence mechanisms intact. We recommend disconnecting the device from the internet and utilizing a professional incident response service or enterprise-grade EDR software to conduct a full forensic sweep.
Is Blackstealer a virus or a Ransomware?
Blackstealer is classified as a Ransomware. Unlike traditional viruses that infect files, modern malware like Blackstealer typically operates as a standalone payload designed to compromise systems, steal data, or deploy secondary stage implants.
What are the main symptoms of a Blackstealer infection?
Symptoms of Blackstealer can include unexpected system slowness, unauthorized outbound network traffic to unknown IP addresses, disabled security software, and suspicious background processes running from AppData or Temp directories.
Related Families (Category: ransomware)
Explore other malware families in the same category:
Protect Your Network Against Ransomwares
Want to prevent Blackstealer and similar threats from compromising your organization? Read our comprehensive defensive guide: Ransomware Protection Guide.
Machine-readable
Get this profile as JSON: https://jordan123234-malware-families-explorer.static.hf.space/api/blackstealer.json
Ecosystem & Interactive Environments
This profile is part of the Malware Families Catalog, a public dataset of 2,899 malware families. The catalog is also published across our ecosystem: Hugging Face, Kaggle, Zenodo, Replit, StackBlitz, CodeSandbox, and CodePen.