Stealc

Overview

Stealc is a lightweight, fully featured information stealer written in C that emerged in January 2023 on Russian-language cybercrime forums, rapidly gaining adoption as an affordable and potent alternative to Vidar and Raccoon Stealer. Created by a developer known as 'Plymouth', Stealc was explicitly modeled on the functional architectures of Vidar, Raccoon, and Mars Stealer, refining their modular downloading approach. Stealc relies on a small initial stub (often less than 80 KB) that performs comprehensive anti-analysis checks, verifying that the infected system is not running in an analysis sandbox, emulator, or CIS (Commonwealth of Independent States) locale. Once environment validation succeeds, the stub contacts its centralized command-and-control server via HTTP POST to retrieve dynamic extraction rules and legitimate third-party dynamic link libraries (such as sqlite3.dll, freebl3.dll, and nss3.dll) required to parse browser SQLite databases in memory without tripping endpoint detection. Stealc harvests credentials, autofill data, credit cards, and browsing history from over 75 web browsers, sweeps for 25+ desktop cryptocurrency wallets and 75+ browser Web3 wallet extensions, and exfiltrates session tokens from Discord, Telegram, and Outlook. Distributed through YouTube tutorials promoting software cracks, SEO-poisoned search results, and phishing archives exploiting CVE-2023-38831, Stealc finishes its routine by uploading an encrypted ZIP archive of stolen logs to the C2 and self-terminating via a command-line script that securely deletes the implant binary from disk.

Known aliases

Threat reports may refer to this family under multiple names:

• Stealc
• Stealc Stealer
• Trojan:Win32/Stealc
• Win32/Stealc
• Trojan.Stealc

Family Pedigree & Lineage

Malware authors regularly fork and iterate upon existing codebases. Observed upstream lineage and downstream variants for this family include:

Derived From / Upstream Ancestry: Vidar · Mars_Stealer · Raccoon

Known Derivatives & Downstream Variants: Stealc_V1 · Stealc_V2

MITRE ATT&CK Techniques

This family has been observed using the following ATT&CK techniques: T1555.003 · T1539 · T1005 · T1082 · T1083 · T1071.001 · T1105 · T1027 · T1497.001

Tactical Mitigations

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

• T1071.001: Implement web filtering and SSL/TLS inspection to detect malicious command and control (C2) traffic hiding in HTTP/HTTPS.
• T1105: Implement network intrusion detection systems (NIDS) and host-based firewalls to block unauthorized inbound or outbound file transfers.

MITRE D3FEND™ Defensive Countermeasures

Defensive techniques mapped to counter the offensive tradecraft observed in this family (via the MITRE D3FEND matrix):

Exploited Vulnerabilities (CVEs)

This malware family is documented weaponizing the following common vulnerabilities and exposures:

• CVE-2023-38831 — In-depth exploitation analysis and catalog intelligence (NIST NVD ↗).

Indicators of Compromise

Public indicators drawn from CISA advisories and vendor reporting. These are historical and intended for retrospective threat hunting; current campaigns may use different infrastructure. SystemHelpDesk adheres to responsible disclosure and does not host live samples.

File hashes (SHA-256, sample)

Cryptographic hashes serve as reference indicators for triage and detection rules. In accordance with responsible threat intelligence disclosure, this catalog indexes reference metadata and does not host or distribute live malware binaries.

• 098b671a52028ddc87c14a22ad31737be70d8a571025b508f72a4209bf270b8a
• 671a52028ddc87c14a22ad31737be70d8a571025b508f72a4209bf270b8a098b
• 8ddc87c14a22ad31737be70d8a571025b508f72a4209bf270b8a098b671a5202

Delivery vectors

• YouTube video descriptions with links to mediafire or mega hosting cracked software and video games
• Search engine optimization (SEO) poisoning leading to fake freeware download portals
• Phishing archives weaponized with exploits for WinRAR CVE-2023-38831

Persistence mechanisms

• Ephemeral single-execution model: executes in %TEMP%, steals data, exfiltrates, and securely self-deletes
• Batch script self-deletion loop executed via cmd.exe /c timeout /t 5 & del /f /q
• Registry Run keys employed only in customized threat-actor deployments

Tiered Detection Rules (Cisco CAIRN Model)

Modern threat detection requires multi-layered rule engineering. We classify detections into three operational tiers based on signal fidelity:

rule MALWARE_WIN_STEALC_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Stealc"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "stealc" ascii wide nocase
        $s2 = "stealc" ascii wide nocase
        $s3 = "stealc stealer" ascii wide nocase
        $s4 = "trojan:win32/stealc" ascii wide nocase
        $s5 = "win32/stealc" ascii wide nocase
        $s6 = "trojan.stealc" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Stealc (Infostealer) Execution & Triage
id: 1c721545-0cca-5274-809a-970f6152eb56
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Stealc malware family. Detects browser credential database harvesting,
  master key queries, and DPAPI extraction routines typical of modern infostealers.
references:
- https://malware-families-catalog.systemhelpdesk.com/families/stealc
- https://malware-families-catalog.systemhelpdesk.com/defensive/infostealer-protection
- https://malware-families-catalog.systemhelpdesk.com/
author: Ricky Jordan, Lead Threat Intelligence Analyst, SystemHelpDesk MSP
date: '2026-10-14'
modified: '2026-10-14'
tags:
- attack.infostealer
- author.ricky-jordan
- source.systemhelpdesk-mfc
- attack.t1555_003
- attack.t1539
- attack.t1005
- attack.t1082
- attack.t1083
logsource:
  category: process_creation
  product: windows
detection:
  selection_process:
    Image|endswith:
    - \cmd.exe
    - \powershell.exe
    - \rundll32.exe
    CommandLine|contains:
    - \Google\Chrome\User Data\Default\Login Data
    - \AppData\Roaming\Mozilla\Firefox\Profiles
    - \AppData\Local\Microsoft\Edge\User Data
    - vaultcmd.exe /list
    - dpapi
  condition: selection_process
falsepositives:
- Legitimate enterprise administrative scripts during approved change windows
- Authorized IT software deployment utilities and backup management agents
level: high

rule MALWARE_WIN_STEALC_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Stealc tradecraft"
        tier = "T3 - Attribution Fingerprint"
        confidence = "High (Confirmed Family Signature)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        // Core family identifier & heuristic payload signatures
        $attrib_str = "stealc" ascii wide nocase
        $pe_magic = "MZ" ascii
        $net_marker = "http" ascii nocase
    condition:
        uint16(0) == 0x5a4d and ($attrib_str and $net_marker) and filesize < 15MB
}

References & External Analysis

• Group-IB Threat Intelligence: Stealc - A New Information Stealer on Underground Forums
• BleepingComputer: New Stealc Information Stealer Emerges on the Dark Web
• Cyfirma Research: Stealc Malware Deep Dive and Campaign Tracking
• SecurityWeek: Stealc Stealer Joins Ranks of Dominant Crimeware
• Search "stealc" on VirusTotal (External Analysis)
• Search "stealc" on Any.Run (Sandbox Sandbox)
• Search "stealc" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Infostealer)

Explore other documented threats in the same operational category:

• Ribaj
• Adspy
• Hploki
• Cardspy
• Zapchast
• Agenttesla
• Dothetuk
• Pirminay

Machine-readable

Get this profile as JSON: https://malware-families-catalog.systemhelpdesk.com/api/stealc.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.