Vidarstealer

Category: advanced_threat · Aliases: Trojan.Vidar, Spyware.VidarStealer, PWS.Win32.Vidar · Sample count (EMBER 2018): 1 · Enrichment: insufficient_information · Updated: 2026-07-01T16:50:17Z

Category: Advanced_ThreatActor: Unknown / CybercriminalIndustry: Global / OpportunisticMotivation: Opportunistic

Overview

Executive Summary

Vidar (also known as Vidar Stealer) is a highly sophisticated, commercially available Information Stealer that emerged in late 2018 as a fork of the infamous Arkei stealer. Sold as Malware-as-a-Service (MaaS) on dark web forums, Vidar is engineered for maximum data extraction. It rapidly harvests user credentials, cryptocurrency wallets, financial data, and system information before exfiltrating the data and (frequently) self-deleting to evade forensic analysis.

Infection Vector and Technical Capabilities

Vidar is distributed via a wide array of vectors depending on the purchasing affiliate. Common methods include malicious spam (malspam) campaigns, fake software cracks (e.g., "KMS Activators"), disguised installers on torrent sites, and delivery via popular exploit kits like RIG or Fallout. Once executed, Vidar initiates a rapid and comprehensive data aggregation routine:

Browser Targeting: Vidar aggressively targets nearly all modern web browsers (Chrome, Firefox, Edge, Opera, Brave). It extracts saved passwords, autofill data, credit card numbers, browsing history, and critically, active session cookies (allowing attackers to bypass MFA).
Wallet Extraction: The stealer is explicitly designed to locate and steal the `wallet.dat` files and recovery phrases associated with dozens of desktop cryptocurrency wallets (e.g., Bitcoin Core, Electrum, Exodus).
Application Data: It harvests credentials from FTP clients (FileZilla), email clients (Thunderbird, Outlook), and secure messaging applications (Telegram, Signal).
Exfiltration and Evasion: The stolen data is compiled into a ZIP archive and transmitted to a C2 server (often utilizing Telegram or Mastodon APIs for covert C2 communication). Once exfiltration is complete, Vidar typically deletes its own executable and the temporary archive to hinder incident response.

Threat Assessment

A Vidar infection is a critical security breach resulting in immediate, catastrophic data loss. The exfiltrated session cookies and credentials allow attackers to completely hijack the user's digital identity, leading to immediate financial theft and the potential compromise of enterprise network access.

Incident Response and Remediation

Assume Total Compromise: Because Vidar steals session cookies, simply changing passwords is insufficient. All active sessions across all web services (M365, Google Workspace, banking portals) must be forcefully terminated, followed by a comprehensive password reset.
Cryptocurrency Asset Movement: If the user managed cryptocurrency on the infected machine, those assets must be immediately transferred to a new, secure wallet, as the private keys are now in the hands of the attackers.
Forensic Analysis: While Vidar often self-deletes, forensic analysis of network logs (PCAPs) can identify the specific C2 infrastructure used for exfiltration, aiding in the generation of IOCs.

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: T1056.001 T1552.001 T1539 T1048

Tactical Mitigations

Based on the techniques used by this family, consider the following defensive strategies:

T1056.001: Implement Endpoint Detection and Response (EDR) to monitor for suspicious API calls related to keystroke interception. Enforce Multi-Factor Authentication (MFA) to render stolen passwords useless.

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_VIDARSTEALER {
    meta:
        description = "Detects Vidarstealer (advanced_threat)"
        author = "SystemHelpdesk Boilerplate Generator"
        date = "2026-07-06"
    strings:
        $s1 = "vidarstealer" ascii wide nocase
        $s2 = "trojan.vidar" ascii wide nocase
        $s3 = "spyware.vidarstealer" ascii wide nocase
        $s4 = "pws.win32.vidar" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

Sigma Rule

title: Suspicious Vidarstealer Activity
id: fdea371d456377371a668f346097e9f9
status: experimental
description: Detects generic indicators of the vidarstealer malware family.
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
        CommandLine|contains:
            - "*vidarstealer*"
            - "*trojan.vidar*"
            - "*spyware.vidarstealer*"
            - "*pws.win32.vidar*"
    condition: selection
level: medium

References & External Analysis

Search "vidarstealer" on VirusTotal (External Analysis)

Frequently Asked Questions

How do I remove the Vidarstealer Advanced_Threat from Windows?

Manual removal of Vidarstealer 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 Vidarstealer a virus or a Advanced_Threat?

Vidarstealer is classified as a Advanced_Threat. Unlike traditional viruses that infect files, modern malware like Vidarstealer typically operates as a standalone payload designed to compromise systems, steal data, or deploy secondary stage implants.

What are the main symptoms of a Vidarstealer infection?

Symptoms of Vidarstealer 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: advanced_threat)

Explore other malware families in the same category:

Protect Your Network Against Advanced_Threats

Want to prevent Vidarstealer and similar threats from compromising your organization? Read our comprehensive defensive guide: Suspect an Infection? What to do.

Need help with an active incident? Published by the SystemHelpdesk team.

Machine-readable

Get this profile as JSON: https://jordanricky1604-ship-it.github.io/malware-families-catalog/api/vidarstealer.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.